From 0d16f10774cdc7bc96bfea7f007c7823e650795d Mon Sep 17 00:00:00 2001
From: Valery Kharseko <vharseko@3a-systems.ru>
Date: Tue, 01 Sep 2026 13:47:43 +0000
Subject: [PATCH] [#879] Skip the validation of a pooled JDBC connection returned a moment ago (#883)
---
opendj-server-legacy/src/test/java/org/opends/server/backends/jdbc/CachedConnectionTestCase.java | 422 ++++++++++++
opendj-server-legacy/src/main/java/org/opends/server/backends/jdbc/CachedConnection.java | 255 ++++++
opendj-server-legacy/src/test/java/org/opends/server/backends/jdbc/JDBCStorageRetryTest.java | 781 ++++++++++++++++++++++
opendj-server-legacy/src/main/java/org/opends/server/backends/jdbc/JDBCStorage.java | 509 ++++++++++++--
opendj-server-legacy/src/test/java/org/opends/server/backends/jdbc/StampConnectionTestCase.java | 16
5 files changed, 1,855 insertions(+), 128 deletions(-)
diff --git a/opendj-server-legacy/src/main/java/org/opends/server/backends/jdbc/CachedConnection.java b/opendj-server-legacy/src/main/java/org/opends/server/backends/jdbc/CachedConnection.java
index 480c3e4..22d63d4 100644
--- a/opendj-server-legacy/src/main/java/org/opends/server/backends/jdbc/CachedConnection.java
+++ b/opendj-server-legacy/src/main/java/org/opends/server/backends/jdbc/CachedConnection.java
@@ -43,10 +43,57 @@
public class CachedConnection implements Connection {
private static final LocalizedLogger logger = LocalizedLogger.getLoggerForThisClass();
+ // What has been reported once already. Every one of these reports a setting rather than an
+ // event - a property that is not a number, a url no bound of this class can reach, a driver
+ // whose property names are not known here - so it does not become truer by being repeated,
+ // and every operation of the backend comes through here.
+ // Declared above every field whose initializer can reach warnOnce(): class variable
+ // initializers run in textual order (JLS 12.4.2), so a set declared below aliveBypassNanos
+ // would still be null the moment a property this class reports on carries a value worth
+ // warning about - a window longer than the ttl, or one that is not a number - and the report
+ // would leave the class uninitializable rather than merely configured oddly.
+ static final Set<String> warnedOnce = ConcurrentHashMap.newKeySet();
+
static final String TTL_PROPERTY = "org.openidentityplatform.opendj.jdbc.ttl";
static final long DEFAULT_TTL_MS = 15000;
/**
+ * How long a pooled connection is handed out without being validated after it was last proven
+ * alive, in ms; 0 validates every borrow, the way this pool did before the window existed.
+ * <p>
+ * The validation of a connection is a round trip of its own - an empty query on postgresql, a
+ * ping on mysql, a round trip of its own on oracle and sql server - and every operation of
+ * this backend pays it next to the single statement the operation came for. It earns that on a
+ * connection that has been sitting in the pool, which the database or a firewall may have
+ * dropped in the meantime; it earns nothing on one that answered a moment ago, which is most
+ * of them under load. So a connection proven alive within this window is trusted rather than
+ * validated, the way the aliveBypassWindow of HikariCP does it.
+ */
+ static final String ALIVE_BYPASS_PROPERTY = "org.openidentityplatform.opendj.jdbc.alive.bypass";
+ static final long DEFAULT_ALIVE_BYPASS_MS = 500;
+
+ /**
+ * The longest window this class uses, whatever {@value #ALIVE_BYPASS_PROPERTY} and the
+ * {@value #TTL_PROPERTY} it is clamped to say. The clamp to the ttl alone does not bound it:
+ * the ttl has no upper bound of its own, and with both set high enough the conversion to
+ * nanoseconds saturates - the window then outlasts every reading it is compared against, and
+ * no connection of the pool is ever validated again. An hour is already far past what this
+ * window is about, which is a connection that answered a moment ago.
+ * <p>
+ * A compile-time constant, so that it holds its value wherever it is read from: the initializer
+ * of {@link #aliveBypassNanos} reaches it, and a field initialized in declaration order would
+ * still be 0 there if it were ever moved below (JLS 12.4.2).
+ */
+ static final long MAX_ALIVE_BYPASS_MS = 60 * 60 * 1000L;
+
+ // Read once, at class initialization: every operation of this backend borrows a connection,
+ // and the borrow is not the place to parse a system property. Not final so that a test can
+ // vary the window without a class loader of its own, and volatile because a non-final static
+ // long is written neither atomically nor visibly to the threads reading it (JLS 17.7) - every
+ // worker of the backend and every replay thread reads this one.
+ static volatile long aliveBypassNanos = TimeUnit.MILLISECONDS.toNanos(getAliveBypassMillis());
+
+ /**
* Bounds the connect and the login of one attempt to establish a connection, in seconds; 0 for
* no bound of its own - the deadline of {@value #POOL_TIMEOUT_PROPERTY} still bounds the
* attempt, since it stands for the whole borrow. Setting both to 0 is what leaves a connect
@@ -111,17 +158,34 @@
private static final Map<String, AtomicLong> lastStallWarning = new ConcurrentHashMap<>();
private static final AtomicLong lastReadBoundWarning = new AtomicLong();
- // What has been reported once already. Every one of these reports a setting rather than an
- // event - a property that is not a number, a url no bound of this class can reach, a driver
- // whose property names are not known here - so it does not become truer by being repeated,
- // and every operation of the backend comes through here.
- static final Set<String> warnedOnce = ConcurrentHashMap.newKeySet();
+ /**
+ * When an operation last reported that the database had dropped a connection of a pool, as a
+ * {@link System#nanoTime()} reading per connection string. A connection proven alive before
+ * that moment is validated on its next borrow whatever the window says: whatever dropped one
+ * connection - a restart, a failover, a network that went away - dropped every connection
+ * established before it, and the window would otherwise hand out the rest of that generation
+ * one by one until the pool runs out of them. It is set by the caller that saw the failure
+ * ({@code JDBCStorage}), never by a validation that failed here: an idle connection the server
+ * reaped is a routine event, and it says nothing about the connection in use that the pool is
+ * about to hand out.
+ */
+ private static final Map<String, Long> poolDistrustedAt = new ConcurrentHashMap<>();
final Connection parent;
- static LoadingCache<String, BlockingQueue<CachedConnection>> cached = Caffeine.newBuilder()
+ // A deque handed out from the end it is returned to: the connection borrowed next is the one
+ // returned last, so under any load the pool keeps reusing its hottest connections instead of
+ // walking round every one it ever opened. That is what gives the window above anything to
+ // bypass - a connection reached only after a whole cycle of the pool has been idle far longer
+ // than the window - and it leaves the connections nothing needs at the cold end of the deque,
+ // where the per-connection idle expiry of #878 can find them. Until that lands, the cold end
+ // is reached only when the whole pool expires, after DEFAULT_TTL_MS with the backend idle.
+ // A deque takes one lock for both of its ends where the queue it replaces took one for each,
+ // so a borrow and a return no longer proceed side by side - against the round trip the window
+ // above saves, and the connect the reuse saves, that lock is not worth a FIFO handoff.
+ static LoadingCache<String, BlockingDeque<CachedConnection>> cached = Caffeine.newBuilder()
.expireAfterAccess(Duration.ofMillis(getCacheTtlMillis()))
- .removalListener((String key, BlockingQueue<CachedConnection> value, RemovalCause cause) -> {
+ .removalListener((String key, BlockingDeque<CachedConnection> value, RemovalCause cause) -> {
for (CachedConnection con : value) {
try {
if (!con.isClosed()) {
@@ -132,7 +196,7 @@
}
}
})
- .build(conStr -> new LinkedBlockingQueue<>());
+ .build(conStr -> new LinkedBlockingDeque<>());
/**
* Returns the time after which an idle pooled connection is closed, as configured by the
@@ -143,6 +207,40 @@
}
/**
+ * Returns the alive window, clamped to the {@value #TTL_PROPERTY} an idle pooled connection is
+ * kept for and to {@link #MAX_ALIVE_BYPASS_MS} behind it. A window longer than the ttl is one
+ * the pool cannot back: it goes on trusting the last answer of a connection past the point the
+ * pool would have closed and replaced it, which is a claim about a connection that is no longer
+ * there. The ttl has no upper bound of its own, though, so the second clamp is what keeps a
+ * value the unit conversion saturates on from leaving every connection of the pool trusted for
+ * the life of the server.
+ * <p>
+ * Read at class initialization, like the ttl it is clamped to, so a value set after that
+ * changes neither.
+ */
+ static long getAliveBypassMillis() {
+ long configured = getNonNegativeProperty(ALIVE_BYPASS_PROPERTY, DEFAULT_ALIVE_BYPASS_MS, "ms");
+ final long ttl = getCacheTtlMillis();
+ if (configured > ttl) {
+ warnOnce(ALIVE_BYPASS_PROPERTY + "=" + configured + ">" + ttl,
+ "The %s window of %d ms is longer than the %d ms of %s a pooled connection is kept for,"
+ + " and is used as %d ms: a connection trusted for longer than the pool keeps it would"
+ + " be trusted past the point the pool closed it",
+ ALIVE_BYPASS_PROPERTY, configured, ttl, TTL_PROPERTY, ttl);
+ configured = ttl;
+ }
+ if (configured > MAX_ALIVE_BYPASS_MS) { // the ttl it was just clamped to has no upper bound of its own
+ warnOnce(ALIVE_BYPASS_PROPERTY + ">" + MAX_ALIVE_BYPASS_MS,
+ "The %s window of %d ms is longer than the %d ms this pool trusts a connection for at most,"
+ + " and is used as %d ms: a longer one saturates the arithmetic it is compared in and"
+ + " leaves every connection of the pool trusted for the life of the server",
+ ALIVE_BYPASS_PROPERTY, configured, MAX_ALIVE_BYPASS_MS, MAX_ALIVE_BYPASS_MS);
+ return MAX_ALIVE_BYPASS_MS;
+ }
+ return configured;
+ }
+
+ /**
* Returns the value of a numeric system property, ignoring a value that is not a non-negative
* number in favor of the default. The unit is the one the property is read in, so that the
* value the message names is not mistaken for another.
@@ -478,6 +576,26 @@
*/
private final boolean poolable;
+ /**
+ * When this connection last answered the database, as a {@link System#nanoTime()} reading:
+ * established - the login and the two round trips that set it up have just answered - or
+ * validated. It is never stamped on the way back into the pool, although that is where a
+ * connection has most recently been used: {@link #close()} ends the transaction, and pgjdbc
+ * short-circuits both {@code rollback()} and {@code commit()} when the transaction state is
+ * IDLE, so on a borrow that issued no statement - {@code JDBCStorage.open()}, a configuration
+ * change that leaves the base DNs alone, an import of nothing - not a byte reaches the server
+ * and the stamp would prove nothing, while marking a connection the database may have dropped
+ * as the freshest one in the pool. Stamping proof rather than use makes the window mean
+ * "validated at most once per window", which is a claim this class can always back.
+ * <p>
+ * It stands for the moment the connection was <em>asked</em>, not the moment its answer was
+ * filed: {@link #distrustPool} is compared against it as an ordering of two moments, and a
+ * proof that took a second to arrive would otherwise outlive a drop reported while it was
+ * still in flight. Reading it early only ever ages the proof, which costs a validation and
+ * never skips one.
+ */
+ private volatile long lastKnownAliveNanos;
+
public CachedConnection(String connectionString, Connection parent) {
this(connectionString, parent, true);
}
@@ -486,6 +604,7 @@
this.connectionString = connectionString;
this.parent = parent;
this.poolable = poolable;
+ this.lastKnownAliveNanos = System.nanoTime();
}
/**
@@ -495,6 +614,22 @@
* not answer into a hang rather than into an error the caller can report.
*/
static Connection getConnection(String connectionString) throws Exception {
+ return getConnection(connectionString, true);
+ }
+
+ /**
+ * Borrows a connection, either trusting the alive window of {@value #ALIVE_BYPASS_PROPERTY} or
+ * validating whatever comes out of the pool.
+ *
+ * @param trusted false for a borrow nothing compensates a dropped connection on. What the
+ * window trades away is the connection that breaks inside it, and {@code JDBCStorage} takes
+ * that off the caller where it can - a write is replayed, a read tells the pool - but the
+ * borrows that open a backend, remove its files or start an import have neither: they issue
+ * their statements far from the borrow, and the one that opens a backend issues none at all,
+ * so a dropped connection would surface out of the {@code rollback()} of its release. Each of
+ * them is one borrow of a cold path, where the round trip the window saves is worth nothing.
+ */
+ static Connection getConnection(String connectionString, boolean trusted) throws Exception {
final ConnectDialect dialect = ConnectDialect.of(connectionString);
reportUnknownDialect(connectionString, dialect);
final long connectTimeoutSeconds = Math.min(
@@ -508,7 +643,7 @@
long backoffMs = 0;
int attempts = 0;
while (true) {
- final CachedConnection pooled = poll(connectionString, waitMs, deadline);
+ final CachedConnection pooled = poll(connectionString, waitMs, deadline, trusted);
if (pooled != null) {
return pooled;
}
@@ -598,27 +733,32 @@
* The validation of a connection costs a round trip, and the pool has no upper bound on the
* number of them it holds, so draining a pool the database no longer answers is given the
* deadline of the borrow as well: past it, establishing a connection is the faster answer.
- * The connection in hand is always validated first, whatever the deadline says - a database at
- * its connection limit has no other source of connections than the ones coming back, and one
- * returned to the pool a moment before the deadline is the very connection this borrow waited
- * for. Only a connection the database no longer answers is closed here.
+ * The connection in hand is always looked at first - trusted or validated, see
+ * {@link #isKnownAlive} - whatever the deadline says: a database at its connection limit has
+ * no other source of connections than the ones coming back, and one returned to the pool a
+ * moment before the deadline is the very connection this borrow waited for. Only a connection
+ * the database no longer answers is closed here.
*/
- private static CachedConnection poll(String connectionString, long waitMs, long deadline) throws InterruptedException {
- CachedConnection con = cached.get(connectionString).poll(waitMs, TimeUnit.MILLISECONDS);
+ private static CachedConnection poll(String connectionString, long waitMs, long deadline, boolean trusted)
+ throws InterruptedException {
+ CachedConnection con = cached.get(connectionString).pollFirst(waitMs, TimeUnit.MILLISECONDS);
while (con != null) {
- if (isUsable(con)) {
+ if (isUsable(con, trusted)) {
return con;
}
closeQuietly(con.parent);
if (System.currentTimeMillis() >= deadline) {
return null;
}
- con = cached.get(connectionString).poll();
+ con = cached.get(connectionString).pollFirst();
}
return null;
}
- private static boolean isUsable(CachedConnection con) {
+ private static boolean isUsable(CachedConnection con, boolean trusted) {
+ if (trusted && isKnownAlive(con)) {
+ return true;
+ }
// The validation needs a bound of its own: isValid(0) means "no timeout" in the JDBC
// contract, and a connection whose socket is half-open answers it no sooner than it
// answers anything else. isValid(n) is not that bound on every driver either - the SQL
@@ -632,6 +772,12 @@
// avoid, and pooling it would hand out a connection carrying a bound of ours
return false;
}
+ // Read before the round trip rather than after it: this stamp is what distrustPool() is
+ // compared against, as an ordering of two moments. A validation is allowed
+ // VALIDATION_TIMEOUT_SECONDS, so a stamp filed once the answer is in can be younger than a
+ // drop another operation reported while it was still in flight - and the connection would
+ // then be trusted for the rest of the window by the very check that exists to stop it.
+ final long provenAt = System.nanoTime();
boolean usable;
try {
usable = con.isValid(VALIDATION_TIMEOUT_SECONDS);
@@ -651,6 +797,7 @@
"the connection is closed rather than pooled")) {
return false; // it would carry the bound of the validation into every statement
}
+ con.lastKnownAliveNanos = provenAt;
return true;
}
@@ -660,6 +807,66 @@
private static final int VALIDATION_BOUND_FAILED = -2;
/**
+ * Whether a connection can be handed out on the strength of the last answer it gave, without a
+ * round trip to ask for another. Three things have to hold: the window is on, the answer is
+ * younger than it, and nothing has reported since that the database dropped a connection of
+ * this pool.
+ * <p>
+ * What the window trades away is the connection that breaks inside it: it is handed out, and
+ * the failure surfaces on the statement of the caller rather than on the borrow. That is where
+ * a connection breaking mid-operation surfaces anyway - but not every caller of this backend
+ * reports such a failure to the client, so the trade is not the caller's alone to bear.
+ * {@code JDBCStorage} answers it on both sides: a write is replayed on a connection the next
+ * attempt borrows of its own, and a read as much as a write marks the pool distrusted, which
+ * closes the window for the rest of the generation the dropped connection belonged to.
+ */
+ private static boolean isKnownAlive(CachedConnection con) {
+ final long window = aliveBypassNanos;
+ if (window <= 0) {
+ return false;
+ }
+ final long provenAt = con.lastKnownAliveNanos;
+ if (System.nanoTime() - provenAt >= window) { // the overflow safe form of the comparison
+ return false;
+ }
+ final Long distrusted = poolDistrustedAt.get(con.connectionString);
+ if (distrusted != null && provenAt - distrusted <= 0) { // the overflow safe form of the comparison
+ return false;
+ }
+ // What the validation this replaces also answered: the removalListener above closes every
+ // connection it finds in the deque when the pool expires, and it iterates a weakly
+ // consistent view, so a connection taken out by a borrow running at the same time can be
+ // closed under it. Answered by the driver out of a flag of its own, not by a round trip.
+ return !isClosed(con.parent);
+ }
+
+ /** Whether the driver reports the connection as closed; one that cannot say is not one to trust. */
+ private static boolean isClosed(Connection con) {
+ try {
+ return con.isClosed();
+ } catch (SQLException e) {
+ return true;
+ }
+ }
+
+ /**
+ * Reports that the database dropped a connection of this pool, so that no connection proven
+ * alive before now is handed out unvalidated again. It is called by the operation that saw the
+ * failure: this class only ever learns of one from the statement it broke, since a borrow
+ * inside the window asks the database nothing.
+ */
+ static void distrustPool(String connectionString) {
+ // merge(later of the two) rather than computeIfAbsent().set(): two operations reporting a
+ // drop at once would otherwise move the distrust point backwards - the later reading is
+ // written first and the earlier one overwrites it - and the AtomicLong of computeIfAbsent
+ // is published holding its initial 0 before set() runs, which a borrow racing it reads as
+ // "never". Not Math.max: nanoTime() has no defined origin, so the readings are compared by
+ // their difference, the way every other comparison of one in this class is.
+ poolDistrustedAt.merge(connectionString, System.nanoTime(),
+ (reported, now) -> now - reported > 0 ? now : reported);
+ }
+
+ /**
* Bounds the socket of a pooled connection for the length of its validation, returning the
* network timeout to put back afterwards - or {@link #VALIDATION_BOUND_LEFT_ALONE} for a
* connection left alone, either because the driver does not take a network timeout or because
@@ -699,6 +906,10 @@
final Properties properties = new Properties();
final boolean readBoundSet = dialect != null && connectTimeoutSeconds > 0
&& dialect.bound(connectionString, properties, connectTimeoutSeconds);
+ // Read before the connect rather than after it, for the reason isUsable() reads it before
+ // the validation: the login answered somewhere inside this attempt, and a stamp taken once
+ // it returned could outlive a drop reported while it was still going on.
+ final long provenAt = System.nanoTime();
final Connection conNew = DriverManager.getConnection(connectionString, properties);
boolean poolable = true;
try {
@@ -715,7 +926,9 @@
closeQuietly(conNew);
throw e;
}
- return new CachedConnection(connectionString, conNew, poolable);
+ final CachedConnection established = new CachedConnection(connectionString, conNew, poolable);
+ established.lastKnownAliveNanos = provenAt;
+ return established;
}
// The second bound of the login is a socket read timeout on mysql, oracle and sql server, in
@@ -1232,7 +1445,9 @@
closeQuietly(parent);
return;
}
- cached.get(connectionString).add(this);
+ // Returned to the end the next borrow takes it from, so that the pool keeps reusing its
+ // hottest connections rather than cycling through every one it ever opened.
+ cached.get(connectionString).addFirst(this);
}
@Override
diff --git a/opendj-server-legacy/src/main/java/org/opends/server/backends/jdbc/JDBCStorage.java b/opendj-server-legacy/src/main/java/org/opends/server/backends/jdbc/JDBCStorage.java
index c94088c..0309d69 100644
--- a/opendj-server-legacy/src/main/java/org/opends/server/backends/jdbc/JDBCStorage.java
+++ b/opendj-server-legacy/src/main/java/org/opends/server/backends/jdbc/JDBCStorage.java
@@ -41,6 +41,7 @@
import java.sql.*;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Predicate;
import static org.opends.server.backends.pluggable.spi.StorageUtils.addErrorMessage;
import static org.opends.server.util.StaticUtils.stackTraceToSingleLineString;
@@ -69,8 +70,17 @@
/** Upper bound the doubled delay is capped at, in milliseconds. */
private static final double MAX_SLEEP_ON_RETRY_MS = 1000.0;
- /** Number of {@link Throwable#getCause()} hops walked when classifying a failure, also a guard against a cycle. */
- private static final int MAX_CAUSE_HOPS = 16;
+ /**
+ * Number of links walked when classifying a failure, also a guard against a chain long enough to matter. One
+ * number for three chains at once - the causes, the next exceptions and the suppressed exceptions are walked
+ * together and counted together - so it is set well above the depth a wrapped failure of this backend reaches:
+ * mssql-jdbc chains every error of one message it received through {@code setNextException}, and a budget spent
+ * on those would never reach the cause the wrapper carries.
+ */
+ private static final int MAX_CHAIN_LINKS = 64;
+
+ /** The budget of {@link #failureScope}, which walks to the end of the chains: see the comment above it. */
+ private static final int EVERY_LINK = Integer.MAX_VALUE;
/** SQL Server error number of the transaction picked as the deadlock victim: "Rerun the transaction". */
private static final int MSSQL_DEADLOCK_VICTIM = 1205;
@@ -90,6 +100,21 @@
private static final Set<String> NON_REPLAYABLE_ROLLBACK_STATES =
Collections.unmodifiableSet(new HashSet<>(Arrays.asList("40002", "40003")));
+ /** SQLState class 08, connection exception: the connection is gone, whatever the statement asked for. */
+ private static final String CONNECTION_FAILURE_CLASS = "08";
+
+ /**
+ * The states outside class 08 that also say the connection is gone rather than the statement wrong. PostgreSQL
+ * announces the connection it is about to drop as 57P01 (admin_shutdown - a pg_terminate_backend of an idle
+ * connection reaper, or a shutdown of the server), 57P02 (crash_shutdown) or 57P03 (cannot_connect_now), and
+ * only the next use of that connection is reported as class 08. They are the states of the list HikariCP
+ * evicts a connection on that a driver of this backend reports: of the rest, JZ0C0 and JZ0C1 belong to a Sybase
+ * driver this backend is not used with, 01002 is a disconnect none of these four drivers reports, and 0A000 is
+ * the standard "feature not supported", which says nothing about the connection at all.
+ */
+ private static final Set<String> CONNECTION_FAILURE_STATES =
+ Collections.unmodifiableSet(new HashSet<>(Arrays.asList("57P01", "57P02", "57P03")));
+
private JDBCBackendCfg config;
public JDBCStorage(JDBCBackendCfg cfg, ServerContext serverContext) {
@@ -143,11 +168,23 @@
return CachedConnection.getConnection(config.getDBDirectory());
}
+ /**
+ * Borrows a connection the pool validates whatever the alive window of
+ * {@link CachedConnection#ALIVE_BYPASS_PROPERTY} says, for the borrows this class compensates a dropped
+ * connection on in no other way: {@link #open(AccessMode)}, {@link #removeStorageFiles()} and the importer
+ * issue their statements far from the borrow, and the open issues none at all, so a connection dropped inside
+ * the window would surface out of the rollback that releases it. One round trip on a path taken once per open,
+ * per import or per removal buys back exactly what master did on every borrow.
+ */
+ Connection getValidatedConnection() throws Exception {
+ return CachedConnection.getConnection(config.getDBDirectory(), false);
+ }
+
AccessMode accessMode=AccessMode.READ_ONLY;
@Override
public void open(AccessMode accessMode) throws Exception {
- try (final Connection con=getConnection()) {
+ try (final Connection con=getValidatedConnection()) {
this.accessMode = accessMode;
storageStatus = StorageStatus.working();
}
@@ -583,42 +620,25 @@
SESSION
}
- // What a failed stamp says about trying again. Both chains of the failure are walked: a driver
- // reports the vendor error of a rejected statement as the next exception of a generic one at
- // least as often as it reports it as the cause, and reading only one of the two would classify
- // a lock timeout as a rejection, which leaves the tree unstamped for the life of the backend
- // over a moment of contention.
+ // What a failed stamp says about trying again. Every chain of the failure is walked, by the walk
+ // every other classifier of this class uses: a driver reports the vendor error of a rejected
+ // statement as the next exception of a generic one at least as often as it reports it as the
+ // cause, the statement of a try-with-resources carries what its close() saw as a suppressed
+ // exception, and reading fewer of them than the others do would classify a connection that broke
+ // as a rejection - which leaves the tree unstamped for the life of the backend. Walked to its end
+ // rather than to MAX_CHAIN_LINKS: the seen set already terminates it, and the verdict weakens
+ // under truncation rather than simply going unnoticed - a SESSION past the budget would come back
+ // as TREE. The strongest verdict wins, so it is asked for in that order.
static FailureScope failureScope(Throwable failure, Dialect dialect) {
- FailureScope scope=FailureScope.TREE;
- final Deque<Throwable> pending=new ArrayDeque<>();
- final Set<Throwable> seen=Collections.newSetFromMap(new IdentityHashMap<Throwable,Boolean>());
- if (failure!=null) {
- pending.push(failure);
+ if (firstLinkMatching(failure, WITH_THE_RELEASE, EVERY_LINK,
+ e -> scopeOf(e, dialect)==FailureScope.SESSION)!=null) {
+ return FailureScope.SESSION;
}
- while (!pending.isEmpty()) {
- final Throwable e=pending.pop();
- if (!seen.add(e)) { // a driver that chains an exception back to itself must not loop this walk
- continue;
- }
- if (e.getCause()!=null) {
- pending.push(e.getCause());
- }
- if (!(e instanceof SQLException)) {
- continue;
- }
- final SQLException sqlException=(SQLException) e;
- if (sqlException.getNextException()!=null) {
- pending.push(sqlException.getNextException());
- }
- final FailureScope found=scopeOf(sqlException, dialect);
- if (found==FailureScope.SESSION) { // nothing further down either chain can weaken this one
- return FailureScope.SESSION;
- }
- if (found==FailureScope.MOMENT) {
- scope=FailureScope.MOMENT;
- }
+ if (firstLinkMatching(failure, WITH_THE_RELEASE, EVERY_LINK,
+ e -> scopeOf(e, dialect)==FailureScope.MOMENT)!=null) {
+ return FailureScope.MOMENT;
}
- return scope;
+ return FailureScope.TREE;
}
// What one exception of the chain says on its own.
@@ -781,7 +801,7 @@
}
final Set<TreeName> trees=listTrees();
if (!trees.isEmpty()) {
- try (final Connection con = getConnection()) {
+ try (final Connection con = getValidatedConnection()) {
try {
for (final TreeName treeName : trees) {
try (final PreparedStatement statement = con.prepareStatement("drop table " + getTableName(treeName))) {
@@ -821,11 +841,43 @@
* counters in instance fields that no attempt resets, so a replay reports twice the entry count of the backend.
* Both are reachable while the server is online, since an export holds no more than a shared backend lock.
* A conflict therefore fails the read here, exactly as it did before the retry of {@link #write} was added.
+ * <p>
+ * A connection the database dropped is not replayed either, for the same reason - but it is reported to the
+ * pool, which cannot notice one on its own: a borrow inside the alive window of
+ * {@link CachedConnection#ALIVE_BYPASS_PROPERTY} asks the database nothing, so the statement that broke is the
+ * only place the drop is ever seen.
*/
@Override
public <T> T read(ReadOperation<T> readOperation) throws Exception {
- try(final Connection con=getConnection()) {
- return readOperation.run(new ReadableTransactionImpl(con));
+ //borrowed outside the try: a connect the pool could not make says nothing about the connections it
+ //holds - mysql reports a server at its connection limit as 08004, which is class 08 like a connection
+ //that broke - and distrusting the pool over it would validate every borrow under the very load the
+ //window exists for, against a server already refusing connections
+ final Connection con=getConnection();
+ boolean dropped=false;
+ try (con) {
+ try {
+ return readOperation.run(new ReadableTransactionImpl(con));
+ } catch (Exception e) {
+ //asked while this read still owns the connection: once the release below has returned it to
+ //the pool, another borrow may hold it and the driver would be answering about that one
+ dropped=isConnectionFailure(e,con);
+ if (dropped) {
+ //told before the release rather than after it: a rollback that never reaches the server -
+ //which is what pgjdbc does with a transaction it left IDLE - leaves the connection poolable,
+ //so the release puts the dropped connection back at the head of the deque, and a borrow
+ //racing the distrust would be handed it unvalidated
+ distrustPool();
+ }
+ throw e;
+ }
+ } catch (Exception e) {
+ //also the release of the connection: its rollback is the one round trip a read that found
+ //nothing makes, so it can be the only place a drop is ever seen
+ if (!dropped && isConnectionFailure(e)) {
+ distrustPool();
+ }
+ throw e;
}
}
@@ -846,6 +898,13 @@
* Only the operation itself is replayed: a failure of {@link #getConnection()} or of the implicit
* {@link Connection#close()} - which returns the connection to the pool after a rollback - leaves the loop, so
* that a completed write is never replayed because releasing its connection failed.
+ * <p>
+ * A connection the database dropped is replayed as well, on a connection the next attempt borrows of its own.
+ * That is what makes the alive window of {@link CachedConnection#ALIVE_BYPASS_PROPERTY} safe to leave on: a
+ * connection handed out unvalidated and found dead costs an attempt rather than the operation, and a write of
+ * the replication replay - which records a failed operation as applied and advances the server state past it,
+ * see #889 - never sees it. Only while nothing of the attempt may have been committed yet, though: see
+ * {@link #replayReason(Throwable, String, boolean, boolean, boolean)}.
*/
@Override
public void write(WriteOperation writeOperation) throws Exception {
@@ -853,42 +912,95 @@
for (int attempt=1;;attempt++) {
Exception failure=null;
String driver=null;
- try (final Connection con=getConnection()) {
+ boolean committing=false;
+ boolean dropped=false;
+ boolean partlyCommitted=false;
+ //borrowed outside the try, for the reason read() borrows outside it: a connect the pool could not
+ //make is not a connection of this pool that broke, and it leaves the loop as it always did
+ final Connection con=getConnection();
+ try (con) {
driver=driverNameOf(con);
final WriteableTransactionTransactionImpl txn=new WriteableTransactionTransactionImpl(con);
try {
writeOperation.run(txn);
+ committing=true;
con.commit();
return;
} catch (Exception e) {
try {
con.rollback();
- } catch (SQLException ex) {}
+ } catch (SQLException ex) {
+ //joined to the failure rather than dropped: a rollback issued on a connection the
+ //database dropped is often the first place - and on a driver that reports a killed
+ //session as a plain vendor error, the only place - the drop is stated outright, and
+ //every classifier below reads the chains of this failure
+ e.addSuppressed(ex);
+ }
+ //asked while this attempt still owns the connection: the release below returns it to the
+ //pool, and the driver would then be answering about whichever borrow holds it next
+ dropped=isConnectionFailure(e,con);
+ if (dropped) {
+ //told before the release rather than after it, for the reason read() tells it there: a
+ //rollback that never reached the server leaves the connection poolable, so the release
+ //returns the dropped connection to the head of the deque, where a borrow racing this
+ //would be handed it unvalidated
+ distrustPool();
+ }
//rethrown, so that a failure of the implicit close() is suppressed into the failure being
//replayed rather than replacing it
failure=e;
throw e;
} finally { // the comment connection lives no longer than the trees it stamped, and no longer
// than the attempt that opened it: a replay stamps on a session of its own
- txn.stampSession.close();
+ partlyCommitted=txn.partlyCommitted;
+ try {
+ txn.stampSession.close();
+ } catch (RuntimeException e) {
+ //the stamp is a diagnostic aid and must not become the outcome of the write: an unchecked
+ //throw out of a driver's close() would otherwise replace the failure being unwound (JLS
+ //14.20.2) - the very one the replay is decided on and the only one that says what went
+ //wrong - or turn a transaction that has just committed into a failure of its own
+ if (failure!=null) {
+ failure.addSuppressed(e);
+ } else {
+ logger.trace(LocalizableMessage.raw("jdbc: unable to close the comment connection: %s",
+ stackTraceToSingleLineString(e)));
+ }
+ }
}
} catch (Exception e) {
- //anything the operation did not throw comes from getConnection() or from the implicit close(),
- //which returns the connection to the pool: neither belongs to the replayed region
+ //anything the operation did not throw comes from around it - the name of the driver, the
+ //transaction, or the implicit close() that returns the connection to the pool: none of them
+ //belongs to the replayed region
if (e!=failure) {
+ //a drop reported by the release of the connection still has to reach the pool, which has no
+ //other way of hearing of it. Only the chains of the failure can be asked for it now: the
+ //connection has been released, and whether it is closed is no longer this attempt's answer
+ if (isConnectionFailure(e)) {
+ distrustPool();
+ }
throw e;
}
}
+ //a drop the release of the connection reported still has to reach the pool, which has no other way
+ //of hearing of it. It is suppressed into the failure being unwound (JLS 14.20.3.1) rather than
+ //replacing it, which is what leaves e==failure and skips the branch above - and it is the very
+ //evidence replayReason() replays the attempt on, so the pool must not be told less than the loop
+ //acts on. The drop of the operation itself was reported before the release, above
+ if (!dropped && isConnectionFailure(failure)) {
+ distrustPool();
+ }
+ final String reason=replayReason(failure,driver,committing,partlyCommitted,dropped);
//System.nanoTime()-giveUpAt is the overflow safe form of the comparison
- if (attempt>=MAX_RETRIES || System.nanoTime()-giveUpAt>=0 || !isRetryableConflict(failure,driver)) {
+ if (reason==null || attempt>=MAX_RETRIES || System.nanoTime()-giveUpAt>=0) {
throw failure;
}
//logged rather than silently absorbed, so that a deployment retrying most of its writes stays observable;
//one line per replay, since an add can emit nine of them and a stack trace each time reads as a failure
- logger.warn(LocalizableMessage.raw("jdbc: replaying the transaction after a conflict, attempt %d of %d: %s",
- attempt, MAX_RETRIES, conflictSummary(failure)));
+ logger.warn(LocalizableMessage.raw("jdbc: replaying the transaction after %s, attempt %d of %d: %s",
+ reason, attempt, MAX_RETRIES, conflictSummary(failure, driver)));
if (logger.isTraceEnabled()) {
- logger.trace("jdbc: the conflict being replayed was %s", stackTraceToSingleLineString(failure));
+ logger.trace("jdbc: the failure being replayed was %s", stackTraceToSingleLineString(failure));
}
try {
//randomized to spread the retries of the transactions that collided, growing to outlast contention
@@ -903,6 +1015,168 @@
}
}
+ /**
+ * Why the operation of a {@link #write} is worth replaying, as the noun phrase the message reporting the replay
+ * names - or null for a failure this loop must not repeat.
+ * <p>
+ * A transaction conflict is replayable whichever phase reported it: the engine rolled the transaction back
+ * before it answered. It is read from the failure of the operation only, never from the release of the
+ * connection - see {@link #isRetryableConflict} - since the release runs after the outcome was decided and
+ * cannot make that claim for it. A connection the database dropped is replayable only while the transaction
+ * had not been committed yet. A drop reported by {@code commit()} leaves the outcome unknown - the server may
+ * have committed and died before the answer reached us - and replaying a write that in fact committed applies
+ * it twice, which is the very reason 40003 is one of {@link #NON_REPLAYABLE_ROLLBACK_STATES}.
+ * <p>
+ * Nothing is replayable once the attempt has committed part of its own work, whatever the failure says. The DDL
+ * of {@link WriteableTransactionTransactionImpl#openTree} and {@link WriteableTransactionTransactionImpl#deleteTree}
+ * commits inside {@link WriteOperation#run}, and mysql and oracle commit before a DDL statement whether asked
+ * to or not, so the attempt no longer rolls back as a whole - and {@link WriteOperation} is only idempotent in
+ * the database. {@code RootContainer.open} opens and registers every entry container of every base DN in one
+ * write: replayed after the trees of the first base DN were created and committed, it registers that base DN a
+ * second time and fails with ERR_ENTRY_CONTAINER_ALREADY_REGISTERED, which masks the failure that caused the
+ * replay and leaves the indexes of the previous attempt behind with their configuration listeners.
+ *
+ * @param committing whether the failure was reported by {@code commit()}, which leaves the outcome unknown
+ * @param partlyCommitted whether the attempt committed part of its work before it failed
+ * @param connectionClosed whether the driver closed the connection under the failure - evidence no SQLState
+ * carries on mssql-jdbc, which reports a killed session as S0001 and closes the connection behind it
+ */
+ static String replayReason(Throwable failure, String driver, boolean committing, boolean partlyCommitted,
+ boolean connectionClosed) {
+ if (partlyCommitted) {
+ return null;
+ }
+ if (isRetryableConflict(failure, driver)) {
+ return "a conflict";
+ }
+ if (!committing && (connectionClosed || isConnectionFailure(failure))) {
+ return "a connection the database dropped";
+ }
+ return null;
+ }
+
+ /**
+ * Whether a failure says the connection is gone rather than the statement rejected, asked of the failure and of
+ * the connection it was raised on. A driver is not required to say so in a SQLState: mssql-jdbc reports a
+ * session killed by {@code KILL}, by the resource governor or by an availability group transition as error 596,
+ * 3980, 10054, 18456 or 4060, and {@code generateStateCode} maps none of them - with xopenStates off, which is
+ * its default, every one of them comes out as {@code "S"+errorState}, measured as S0001. What the driver does
+ * do is close the connection for any error of severity 20 and above, before it throws.
+ * <p>
+ * Asked only while the operation that failed still owns the connection: a released one is back in the pool and
+ * may already have been handed to another borrow, whose state it would then be answering about.
+ */
+ static boolean isConnectionFailure(Throwable failure, Connection con) {
+ return isConnectionFailure(failure) || isClosed(con);
+ }
+
+ /** Whether the driver reports the connection as closed; one that cannot answer is taken as closed. */
+ private static boolean isClosed(Connection con) {
+ try {
+ return con.isClosed();
+ } catch (SQLException e) {
+ return true;
+ }
+ }
+
+ /**
+ * Whether a failure says the connection is gone rather than the statement rejected: the database dropped it,
+ * restarted, failed over, or the network did.
+ * <p>
+ * Both chains of the failure are walked, for the reason {@link #failureScope} walks both: a driver reports the
+ * error that says what happened as the next exception of a generic one at least as often as it reports it as
+ * the cause, and mssql-jdbc chains every error of a message it received that way. The suppressed exceptions are
+ * walked with them, since the rollback and the release of a connection report a drop there - a write whose
+ * operation failed for its own reasons carries the drop of its {@code close()} as a suppressed exception (JLS
+ * 14.20.3.1) rather than as a cause. The walk starts at the failure this class was handed because it reaches it
+ * wrapped in a {@link StorageRuntimeException}, and a caller such as {@code EntryContainer.addEntry} may wrap
+ * it once more.
+ */
+ static boolean isConnectionFailure(Throwable failure) {
+ return firstLinkMatching(failure, WITH_THE_RELEASE, JDBCStorage::saysTheConnectionIsGone)!=null;
+ }
+
+ /**
+ * Whether {@link #firstLinkMatching} reads the suppressed exceptions along with the causes and the next
+ * exceptions. They are where the release of the connection reports what it saw - a rollback that failed as the
+ * attempt was unwound is suppressed into the failure being unwound (JLS 14.20.3.1) - so a question about the
+ * connection is asked of them, and a question about what the engine did with the transaction is not: the
+ * release runs after the outcome was decided, and cannot speak for it.
+ */
+ private static final boolean WITH_THE_RELEASE=true;
+ private static final boolean WITHOUT_THE_RELEASE=false;
+
+ /**
+ * The first {@link SQLException} of the chains of a failure that answers the given question, or null where none
+ * does. Every classifier of this class walks the failure this way, so that none of them reads a chain the others
+ * act on: what makes a write replayable must also be what the pool is told about and what the replay logs.
+ */
+ private static SQLException firstLinkMatching(Throwable failure, boolean withTheRelease,
+ Predicate<SQLException> matches) {
+ return firstLinkMatching(failure, withTheRelease, MAX_CHAIN_LINKS, matches);
+ }
+
+ /** The walk above, with the number of links it is allowed to look at. */
+ private static SQLException firstLinkMatching(Throwable failure, boolean withTheRelease, int links,
+ Predicate<SQLException> matches) {
+ final Deque<Throwable> pending=new ArrayDeque<>();
+ final Set<Throwable> seen=Collections.newSetFromMap(new IdentityHashMap<Throwable,Boolean>());
+ if (failure!=null) {
+ pending.push(failure);
+ }
+ while (!pending.isEmpty() && seen.size()<links) {
+ final Throwable e=pending.pop();
+ if (!seen.add(e)) { // a driver that chains an exception back to itself must not loop this walk
+ continue;
+ }
+ if (e.getCause()!=null) {
+ pending.push(e.getCause());
+ }
+ if (withTheRelease) {
+ for (final Throwable suppressed : e.getSuppressed()) {
+ pending.push(suppressed);
+ }
+ }
+ if (!(e instanceof SQLException)) {
+ continue;
+ }
+ final SQLException sqlException=(SQLException) e;
+ if (sqlException.getNextException()!=null) {
+ pending.push(sqlException.getNextException());
+ }
+ if (matches.test(sqlException)) {
+ return sqlException;
+ }
+ }
+ return null;
+ }
+
+ /**
+ * What one exception of the chain says on its own. The types are asked before the SQLState, the way
+ * {@link #scopeOf} asks them: they are what the JDBC contract gives a driver to say the connection is gone, and
+ * a driver that raises one of them has said so whatever state it filled in. Oracle reports ORA-03113, ORA-00028
+ * and ORA-01089 as {@link SQLRecoverableException} and happens to map them to 08006 as well; the type is what
+ * makes that robust rather than lucky.
+ */
+ private static boolean saysTheConnectionIsGone(SQLException e) {
+ if (e instanceof SQLRecoverableException || e instanceof SQLNonTransientConnectionException
+ || e instanceof SQLTransientConnectionException) {
+ return true;
+ }
+ final String state=String.valueOf(e.getSQLState());
+ return state.startsWith(CONNECTION_FAILURE_CLASS) || CONNECTION_FAILURE_STATES.contains(state);
+ }
+
+ /**
+ * Tells the pool of this backend that the database dropped a connection, so that the ones it still holds from
+ * before the drop are validated on their next borrow instead of being trusted for the rest of the alive window.
+ * A dropped connection is rarely alone: a restart, a failover or a network that went away takes every
+ * connection established before it, and the pool has no other way of hearing about any of them.
+ */
+ private void distrustPool() {
+ CachedConnection.distrustPool(config.getDBDirectory());
+ }
+
/** Returns the randomized delay before the given attempt is replayed, doubling with each attempt up to a cap. */
static long retryDelayMillis(int attempt) {
final double bound=Math.min(MAX_SLEEP_ON_RETRY_MS, BASE_SLEEP_ON_RETRY_MS * (1 << Math.min(attempt-1, 5)));
@@ -912,9 +1186,11 @@
/**
* Returns whether the given failure carries a transaction conflict that replaying the operation can resolve.
* <p>
- * The conflict is looked up along the whole cause chain because it reaches this class wrapped: a deadlock in
- * {@code put} arrives as {@code StorageRuntimeException(SQLException)}, and a caller such as
- * {@code EntryContainer.addEntry} may wrap it once more.
+ * The conflict is looked up along every chain of the failure, for the reason {@link #isConnectionFailure} walks
+ * them all: it reaches this class wrapped - a deadlock in {@code put} arrives as
+ * {@code StorageRuntimeException(SQLException)}, and a caller such as {@code EntryContainer.addEntry} may wrap it
+ * once more - and a driver reports the error that says what happened as the next exception of a generic one at
+ * least as often as it reports it as the cause.
* <p>
* The standard class 40 states carry the conflict of most engines - 40P01 for PostgreSQL, 40001 for SQL Server
* and for MySQL, whose driver replaces the server side HY000 of a deadlock and of a lock wait timeout with
@@ -928,12 +1204,12 @@
* that are excluded from that match.
*/
static boolean isRetryableConflict(Throwable t, String driver) {
- for (int hop=0; t!=null && hop<MAX_CAUSE_HOPS; t=t.getCause(), hop++) {
- if (t instanceof SQLException && isConflict((SQLException) t, driver)) {
- return true;
- }
- }
- return false;
+ // without the suppressed exceptions, unlike isConnectionFailure(): a conflict is replayed whichever phase
+ // reported it, on the strength of the engine having rolled the transaction back before it answered - and
+ // the release of the connection runs after the outcome was decided and cannot make that claim. A class 40
+ // raised there would otherwise replay a transaction commit() left in doubt, which is what the committing
+ // guard of replayReason() exists to prevent
+ return firstLinkMatching(t, WITHOUT_THE_RELEASE, e -> isConflict(e, driver))!=null;
}
private static boolean isConflict(SQLException e, String driver) {
@@ -951,18 +1227,30 @@
}
/**
- * Returns the SQLState and vendor error number of the first {@link SQLException} of the given cause chain, which
- * is what identifies a conflict, so that a replay can be logged without a stack trace on every attempt.
+ * Returns the SQLState and vendor error number of the exception a replay was decided on, so that a replay can be
+ * logged without a stack trace on every attempt. That line is the only record a replay leaves, so it names the
+ * link the decision was taken on rather than the first {@link SQLException} of the failure: a write whose
+ * operation failed for its own reasons and whose release then reported a drop is replayed on the class 08
+ * suppressed into it, and naming the state of the rejected statement instead would describe a replay that did
+ * not happen. Falls back to the first SQLException of the failure, and to the failure itself where it carries
+ * none.
*/
- static String conflictSummary(Throwable failure) {
- Throwable t=failure;
- for (int hop=0; t!=null && hop<MAX_CAUSE_HOPS; t=t.getCause(), hop++) {
- if (t instanceof SQLException) {
- final SQLException e=(SQLException) t;
- return "SQLState "+e.getSQLState()+", error "+e.getErrorCode()+": "+e.getMessage();
- }
+ static String conflictSummary(Throwable failure, String driver) {
+ // asked in the order replayReason() asks it, and of the same chains, so that the line names the link the
+ // decision was taken on rather than one that merely resembles it
+ SQLException named=firstLinkMatching(failure, WITHOUT_THE_RELEASE, e -> isConflict(e, driver));
+ if (named==null) {
+ named=firstLinkMatching(failure, WITH_THE_RELEASE, JDBCStorage::saysTheConnectionIsGone);
}
- return String.valueOf(failure);
+ if (named==null) {
+ // without the release, so that the line names the statement that failed rather than the rollback
+ // behind it: this is the fallback of a replay decided on isClosed(con) alone, where neither chain
+ // carries a verdict, and the walk reaches the suppressed exceptions before the cause
+ named=firstLinkMatching(failure, WITHOUT_THE_RELEASE, e -> true);
+ }
+ return named==null
+ ? String.valueOf(failure)
+ : "SQLState "+named.getSQLState()+", error "+named.getErrorCode()+": "+named.getMessage();
}
static final byte[] NULL=new byte[]{(byte)0};
@@ -1060,6 +1348,18 @@
// write() (and by ImporterImpl.close()) when the transaction is done with.
final StampSession stampSession=new StampSession();
+ /**
+ * Whether this transaction has committed part of its own work, which takes the attempt out of the
+ * replay of {@link JDBCStorage#write}: what it did no longer rolls back as a whole, and a
+ * {@link WriteOperation} is only idempotent in the database.
+ * <p>
+ * Raised by {@link #commitStatement} alone, which is what every statement of this transaction that
+ * commits goes through - never once for a method that may issue one: a catalog read deciding that the
+ * statement is not needed commits nothing, and a transaction the engine rolled back whole is still worth
+ * replaying. Which side of the statement the flag goes up on is the engine's answer, see there.
+ */
+ boolean partlyCommitted;
+
public WriteableTransactionTransactionImpl(Connection con) {
super(con);
//captured once rather than read per operation: the access mode of the storage is mutable state -
@@ -1075,6 +1375,36 @@
}
}
+ /**
+ * Issues a statement that ends in a commit, raising {@link #partlyCommitted} at the moment the attempt
+ * stops rolling back as a whole.
+ * <p>
+ * mysql and oracle commit before a DDL statement whether asked to or not, so there the work behind it is
+ * committed by the statement itself and the flag has to be up before it is issued: the statement that
+ * fails has committed everything before it just as surely as the one that succeeds. postgresql and sql
+ * server run DDL inside the transaction, and a DML statement commits of its own accord nowhere - one that
+ * fails there has committed nothing, {@link JDBCStorage#write} rolls the attempt back whole, and a flag
+ * raised in front of it would take a conflict the engine itself undid out of the replay. On those the
+ * flag goes up in front of the commit instead, which is the call that leaves the outcome of the
+ * transaction unknown when it fails.
+ *
+ * @param ddl whether the statement is a DDL one, which two of the four engines commit before
+ */
+ private void commitStatement(String sql, boolean ddl) throws SQLException {
+ partlyCommitted|=ddl && commitsBeforeDdl();
+ try (final PreparedStatement statement=con.prepareStatement(sql)) {
+ execute(statement);
+ partlyCommitted=true; // a commit that fails leaves the outcome unknown, which is no more replayable
+ con.commit();
+ }
+ }
+
+ /** Whether this engine commits the transaction before a DDL statement whether asked to or not. */
+ private boolean commitsBeforeDdl() {
+ final String driverName=driverNameOf(con);
+ return driverName.contains("mysql") || driverName.contains("oracle");
+ }
+
boolean isExistsTable(TreeName treeName) {
final String tableName = getTableName(treeName);
try {
@@ -1114,10 +1444,16 @@
public void openTree(TreeName treeName, boolean createOnDemand) {
if (createOnDemand) {
checkReadOnly();
+ // Every statement below is a DDL that commits, and each raises partlyCommitted through
+ // commitStatement() rather than once for the method: every one of them is guarded by a
+ // catalog read, so on an existing backend this method issues nothing at all. Raising the
+ // flag for a catalog read that commits nothing would make the whole attempt unreplayable -
+ // the conflict replay of #867 as much as the drop replay, since replayReason() reads the
+ // flag before it asks anything else - and RootContainer.open() opens every tree of every
+ // base DN in a single write, whose first act is one of these.
if (!isExistsTable(treeName)) {
- try (final PreparedStatement statement=con.prepareStatement("create table "+getTableName(treeName)+" ("+getTableDialect()+")")){
- execute(statement);
- con.commit();
+ try {
+ commitStatement("create table "+getTableName(treeName)+" ("+getTableDialect()+")", true);
}catch (SQLException e) {
throw new StorageRuntimeException(e);
}
@@ -1126,19 +1462,21 @@
final String driverName=driverNameOf(con);
final String tableName=getTableName(treeName);
if (driverName.contains("postgres")) {
- try (final PreparedStatement statement=con.prepareStatement("create index if not exists k_"+tableName.substring("opendj_".length())+" on "+tableName+" (k)")){
- execute(statement);
- con.commit();
+ try {
+ // asked although postgresql has "create index if not exists": that statement commits
+ // whether it creates anything or not, and this is the engine of every default
+ // deployment - unguarded, it would take every write that opens a tree out of the
+ // conflict replay, RootContainer.open() and its ~25 trees per suffix included
+ if (!isExistsIndex(tableName,"k_"+tableName.substring("opendj_".length()))) {
+ commitStatement("create index if not exists k_"+tableName.substring("opendj_".length())+" on "+tableName+" (k)", true);
+ }
}catch (SQLException e) {
throw new StorageRuntimeException(e);
}
}else if (driverName.contains("mysql")) {
try {
if (!isExistsIndex(tableName,"k_"+tableName.substring("opendj_".length()))) { // mysql has no "create index if not exists"
- try (final PreparedStatement statement=con.prepareStatement("create index k_"+tableName.substring("opendj_".length())+" on "+tableName+" (k)")){
- execute(statement);
- con.commit();
- }
+ commitStatement("create index k_"+tableName.substring("opendj_".length())+" on "+tableName+" (k)", true);
}
}catch (SQLException e) {
throw new StorageRuntimeException(e);
@@ -1147,10 +1485,7 @@
try {
// oracle has no "create index if not exists"; unquoted identifiers are stored in uppercase
if (!isExistsIndex(tableName.toUpperCase(),"k_"+tableName.substring("opendj_".length()))) {
- try (final PreparedStatement statement=con.prepareStatement("create index k_"+tableName.substring("opendj_".length())+" on "+tableName+" (k)")){
- execute(statement);
- con.commit();
- }
+ commitStatement("create index k_"+tableName.substring("opendj_".length())+" on "+tableName+" (k)", true);
}
}catch (SQLException e) {
throw new StorageRuntimeException(e);
@@ -1177,9 +1512,8 @@
public void clearTree(TreeName treeName) {
checkReadOnly();
- try (final PreparedStatement statement=con.prepareStatement("delete from "+getTableName(treeName))){
- execute(statement);
- con.commit();
+ try { // the commit takes the attempt out of the replay: it commits the delete, and everything before it
+ commitStatement("delete from "+getTableName(treeName), false);
}catch (SQLException e) {
throw new StorageRuntimeException(e);
}
@@ -1189,9 +1523,8 @@
public void deleteTree(TreeName treeName) {
checkReadOnly();
if (isExistsTable(treeName)) {
- try (final PreparedStatement statement = con.prepareStatement("drop table " + getTableName(treeName))) {
- execute(statement);
- con.commit();
+ try {
+ commitStatement("drop table " + getTableName(treeName), true);
} catch (SQLException e) {
throw new StorageRuntimeException(e);
}
@@ -1534,7 +1867,7 @@
}
}
try {
- con = getConnection();
+ con = getValidatedConnection();
}catch (Exception e){
throw new StorageRuntimeException(e);
}
diff --git a/opendj-server-legacy/src/test/java/org/opends/server/backends/jdbc/CachedConnectionTestCase.java b/opendj-server-legacy/src/test/java/org/opends/server/backends/jdbc/CachedConnectionTestCase.java
index 0caad17..c98f280 100644
--- a/opendj-server-legacy/src/test/java/org/opends/server/backends/jdbc/CachedConnectionTestCase.java
+++ b/opendj-server-legacy/src/test/java/org/opends/server/backends/jdbc/CachedConnectionTestCase.java
@@ -19,8 +19,14 @@
import org.testng.annotations.AfterClass;
import org.testng.annotations.AfterMethod;
import org.testng.annotations.BeforeClass;
+import org.testng.annotations.BeforeMethod;
+import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.lang.reflect.Field;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.sql.Connection;
@@ -52,11 +58,13 @@
import static org.mockito.Mockito.inOrder;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;
import static org.testng.Assert.assertEquals;
import static org.testng.Assert.assertFalse;
import static org.testng.Assert.assertNotNull;
+import static org.testng.Assert.assertNotSame;
import static org.testng.Assert.assertNull;
import static org.testng.Assert.assertSame;
import static org.testng.Assert.assertTrue;
@@ -83,6 +91,9 @@
private final StubDriver stub = new StubDriver();
+ /** The window as this JVM was started with it, put back after every test that varies it. */
+ private static final long CONFIGURED_ALIVE_BYPASS_NANOS = CachedConnection.aliveBypassNanos;
+
@BeforeClass
public void registerStubDriver() throws Exception {
DriverManager.registerDriver(stub);
@@ -93,13 +104,26 @@
DriverManager.deregisterDriver(stub);
}
+ /**
+ * Most of the tests below seed the pool by hand, and a connection built a moment ago is inside
+ * the alive window - they are about what the validation of a borrow does, so the window is off
+ * unless the test at hand is one of the window's own.
+ */
+ @BeforeMethod
+ public void validateEveryBorrow() {
+ CachedConnection.aliveBypassNanos = 0;
+ }
+
@AfterMethod
public void clearProperties() {
System.clearProperty(CachedConnection.CONNECT_TIMEOUT_PROPERTY);
System.clearProperty(CachedConnection.POOL_TIMEOUT_PROPERTY);
+ System.clearProperty(CachedConnection.TTL_PROPERTY);
+ System.clearProperty(CachedConnection.ALIVE_BYPASS_PROPERTY);
// what has been reported once is remembered for the life of the jvm: left standing, the key
// of one test is what the next one finds when it asserts that it reported something itself
CachedConnection.warnedOnce.clear();
+ CachedConnection.aliveBypassNanos = CONFIGURED_ALIVE_BYPASS_NANOS;
}
/**
@@ -546,7 +570,7 @@
final Connection pooled = mock(Connection.class);
when(pooled.isValid(anyInt())).thenReturn(true);
when(pooled.getNetworkTimeout()).thenReturn(0);
- CachedConnection.cached.get(url).add(new CachedConnection(url, pooled));
+ seedPool(url, pooled);
final Connection borrowed = CachedConnection.getConnection(url);
@@ -572,7 +596,7 @@
when(pooled.isValid(anyInt())).thenReturn(true);
doThrow(new SQLException("the driver took the bound and then failed"))
.when(pooled).setNetworkTimeout(any(Executor.class), anyInt());
- CachedConnection.cached.get(url).add(new CachedConnection(url, pooled));
+ seedPool(url, pooled);
final Connection fresh = mock(Connection.class);
stub.answerWith(fresh);
@@ -615,7 +639,7 @@
final Connection pooled = mock(Connection.class);
when(pooled.isValid(anyInt())).thenReturn(true);
when(pooled.getNetworkTimeout()).thenReturn(2000);
- CachedConnection.cached.get(url).add(new CachedConnection(url, pooled));
+ seedPool(url, pooled);
assertNotNull(CachedConnection.getConnection(url));
@@ -639,7 +663,7 @@
Thread.sleep(500); // a database that no longer answers: every validation waits out its bound
return false;
});
- CachedConnection.cached.get(url).add(new CachedConnection(url, stale));
+ seedPool(url, stale);
}
final Connection fresh = mock(Connection.class);
stub.answerWith(fresh);
@@ -658,7 +682,7 @@
final String url = StubDriver.PREFIX + "broken-pooled";
final Connection stale = mock(Connection.class);
when(stale.isValid(anyInt())).thenReturn(false);
- CachedConnection.cached.get(url).add(new CachedConnection(url, stale));
+ seedPool(url, stale);
final Connection fresh = mock(Connection.class);
when(fresh.isValid(anyInt())).thenReturn(true);
stub.answerWith(fresh);
@@ -682,7 +706,7 @@
final String url = StubDriver.PREFIX + "validation-unchecked";
final Connection broken = mock(Connection.class);
when(broken.isValid(anyInt())).thenThrow(new IllegalStateException("driver internal"));
- CachedConnection.cached.get(url).add(new CachedConnection(url, broken));
+ seedPool(url, broken);
final Connection fresh = mock(Connection.class);
stub.answerWith(fresh);
@@ -1273,8 +1297,7 @@
});
final Connection good = mock(Connection.class);
when(good.isValid(anyInt())).thenReturn(true);
- CachedConnection.cached.get(url).add(new CachedConnection(url, stale));
- CachedConnection.cached.get(url).add(new CachedConnection(url, good));
+ seedPool(url, stale, good);
final Connection fresh = mock(Connection.class);
stub.answerWith(fresh);
System.setProperty(CachedConnection.POOL_TIMEOUT_PROPERTY, "1");
@@ -1300,7 +1323,7 @@
final Connection reaped = mock(Connection.class);
when(reaped.getNetworkTimeout()).thenReturn(0);
when(reaped.isValid(anyInt())).thenReturn(false);
- CachedConnection.cached.get(url).add(new CachedConnection(url, reaped));
+ seedPool(url, reaped);
final Connection fresh = mock(Connection.class);
stub.answerWith(fresh);
@@ -1333,6 +1356,387 @@
"a connection still carrying the read bound of its login went back into the pool");
}
+ /**
+ * The case the window exists for: the connection this borrow takes out answered the database a
+ * moment ago, and asking it again costs the round trip the operation came to make.
+ */
+ @Test(timeOut = 120000)
+ public void testAConnectionProvenAliveIsNotValidatedAgainWithinTheWindow() throws Exception {
+ final String url = StubDriver.PREFIX + "within-the-window";
+ CachedConnection.aliveBypassNanos = TimeUnit.HOURS.toNanos(1);
+ final Connection parent = mock(Connection.class);
+ when(parent.isValid(anyInt())).thenReturn(true);
+ stub.answerWith(parent);
+
+ final Connection first = CachedConnection.getConnection(url); // established: it has just answered
+ first.close();
+ final Connection second = CachedConnection.getConnection(url);
+
+ assertSame(second, first, "the pooled connection was not the one handed back");
+ assertEquals(stub.attempts.get(), 1, "the pool established a second connection");
+ verify(parent, never()).isValid(anyInt());
+ }
+
+ /** Past the window it is the connection the database or a firewall may have dropped meanwhile. */
+ @Test(timeOut = 120000)
+ public void testAConnectionIsValidatedAgainOnceTheWindowHasPassed() throws Exception {
+ final String url = StubDriver.PREFIX + "past-the-window";
+ CachedConnection.aliveBypassNanos = TimeUnit.MILLISECONDS.toNanos(1);
+ final Connection parent = mock(Connection.class);
+ when(parent.isValid(anyInt())).thenReturn(true);
+ stub.answerWith(parent);
+
+ final Connection first = CachedConnection.getConnection(url);
+ first.close();
+ Thread.sleep(20);
+ final Connection second = CachedConnection.getConnection(url);
+
+ assertSame(second, first);
+ verify(parent).isValid(CachedConnection.VALIDATION_TIMEOUT_SECONDS);
+ }
+
+ /** The window switched off validates every borrow, the way this pool did before it existed. */
+ @Test(timeOut = 120000)
+ public void testAWindowOfZeroValidatesEveryBorrow() throws Exception {
+ final String url = StubDriver.PREFIX + "window-of-zero";
+ CachedConnection.aliveBypassNanos = 0;
+ final Connection parent = mock(Connection.class);
+ when(parent.isValid(anyInt())).thenReturn(true);
+ stub.answerWith(parent);
+
+ final Connection first = CachedConnection.getConnection(url);
+ first.close();
+ final Connection second = CachedConnection.getConnection(url);
+
+ assertSame(second, first);
+ verify(parent).isValid(CachedConnection.VALIDATION_TIMEOUT_SECONDS);
+ }
+
+ /**
+ * A connection is trusted for the window that follows the last answer it gave, never for the
+ * window that follows its return to the pool. pgjdbc short-circuits both rollback() and
+ * commit() when the transaction state is IDLE, so a borrow that issued no statement - the open
+ * of a backend, a configuration change that leaves the base DNs alone, an import of nothing -
+ * puts a connection back without a byte reaching the server: stamping the return would mark a
+ * connection the database dropped meanwhile as the freshest one in the pool.
+ */
+ @Test(timeOut = 120000)
+ public void testTheReturnToThePoolIsNotTakenForProofOfLife() throws Exception {
+ final String url = StubDriver.PREFIX + "silent-return";
+ CachedConnection.aliveBypassNanos = TimeUnit.MILLISECONDS.toNanos(50);
+ final Connection dropped = mock(Connection.class);
+ when(dropped.isValid(anyInt())).thenReturn(false); // dropped while it was out of the pool
+ stub.answerWith(dropped);
+
+ final Connection borrowed = CachedConnection.getConnection(url);
+ Thread.sleep(80); // the answer of the login ages out of the window
+ borrowed.close(); // and the rollback of this return never leaves the driver
+ final Connection fresh = mock(Connection.class);
+ when(fresh.isValid(anyInt())).thenReturn(true);
+ stub.answerWith(fresh);
+
+ final Connection next = CachedConnection.getConnection(url);
+
+ verify(dropped).isValid(CachedConnection.VALIDATION_TIMEOUT_SECONDS);
+ verify(dropped).close();
+ assertSame(((CachedConnection) next).parent, fresh,
+ "a connection the database dropped was handed out on the strength of its return to the pool");
+ }
+
+ /**
+ * A proof taken while the database was going away does not outlive the distrust that reported it.
+ * <p>
+ * The stamp stands for the moment the connection was asked, not the moment its answer was filed:
+ * a validation is given {@link CachedConnection#VALIDATION_TIMEOUT_SECONDS}, and one that started
+ * before another operation reported a drop and returned after it would otherwise be the younger of
+ * the two. The connection would then be handed out unvalidated for the rest of the window - and
+ * LIFO puts it at the head of the deque, so it is the very one the next borrow takes - by the
+ * check that exists to stop exactly that.
+ */
+ @Test(timeOut = 120000)
+ public void testAProofTakenWhileTheDatabaseWentAwayIsNotTrusted() throws Exception {
+ final String url = StubDriver.PREFIX + "proof-across-a-drop";
+ CachedConnection.aliveBypassNanos = TimeUnit.HOURS.toNanos(1); // nothing here ages out of the window
+ final AtomicInteger validations = new AtomicInteger();
+ final Connection parent = mock(Connection.class);
+ // the database goes away while this validation is in flight: another operation of the backend
+ // reports the drop of its own connection before this one has answered
+ when(parent.isValid(anyInt())).thenAnswer(invocation -> {
+ CachedConnection.distrustPool(url);
+ validations.incrementAndGet();
+ return true;
+ });
+ stub.answerWith(parent);
+
+ CachedConnection.getConnection(url).close(); // established and returned, proven by its login
+ CachedConnection.distrustPool(url); // an operation reports a drop: what the pool holds predates it
+ CachedConnection.getConnection(url).close(); // validated, and a second drop is reported while it is
+
+ final Connection borrowed = CachedConnection.getConnection(url);
+
+ assertEquals(validations.get(), 2,
+ "a connection was trusted on a proof that started before the drop it is compared against");
+ assertSame(((CachedConnection) borrowed).parent, parent, "the connection answered and was still discarded");
+ }
+
+ /**
+ * The pool hands out the connection returned last. Without it the window would rarely apply: a
+ * connection reached only after a whole cycle of the pool has been idle far longer than it.
+ */
+ @Test(timeOut = 120000)
+ public void testTheConnectionReturnedLastIsBorrowedFirst() throws Exception {
+ final String url = StubDriver.PREFIX + "returned-last";
+ CachedConnection.aliveBypassNanos = TimeUnit.HOURS.toNanos(1);
+ final Connection older = mock(Connection.class);
+ when(older.isValid(anyInt())).thenReturn(true);
+ stub.answerWith(older);
+ final Connection first = CachedConnection.getConnection(url);
+ final Connection newer = mock(Connection.class);
+ when(newer.isValid(anyInt())).thenReturn(true);
+ stub.answerWith(newer);
+ final Connection second = CachedConnection.getConnection(url);
+ assertNotSame(second, first);
+ first.close();
+ second.close();
+
+ final Connection borrowed = CachedConnection.getConnection(url);
+
+ assertSame(((CachedConnection) borrowed).parent, newer, "the pool cycled round to its coldest connection");
+ }
+
+ /**
+ * Whatever dropped one connection - a restart, a failover, a network that went away - dropped
+ * every connection established before it, and a borrow inside the window asks the database
+ * nothing: so the operation that saw the failure tells the pool, and the rest of that
+ * generation is validated once before it is trusted again.
+ */
+ @Test(timeOut = 120000)
+ public void testThePoolIsValidatedAgainAfterTheDatabaseDroppedAConnection() throws Exception {
+ final String url = StubDriver.PREFIX + "distrusted-generation";
+ CachedConnection.aliveBypassNanos = TimeUnit.HOURS.toNanos(1);
+ final Connection parent = mock(Connection.class);
+ when(parent.isValid(anyInt())).thenReturn(true);
+ stub.answerWith(parent);
+ CachedConnection.getConnection(url).close();
+
+ CachedConnection.distrustPool(url);
+ final Connection next = CachedConnection.getConnection(url);
+ next.close();
+ CachedConnection.getConnection(url).close();
+
+ // once for the generation the drop condemned, and not again for the borrow behind it
+ verify(parent, times(1)).isValid(CachedConnection.VALIDATION_TIMEOUT_SECONDS);
+ }
+
+ /**
+ * The whole of the trade the window makes, end to end: a connection the database dropped
+ * inside the window is handed out unvalidated - that is the cost - the operation it broke
+ * reports the drop, and from there the pool validates the generation the drop condemned
+ * instead of handing out the rest of it the same way.
+ */
+ @Test(timeOut = 120000)
+ public void testAConnectionDroppedInsideTheWindowIsHandedOutOnceAndThenValidated() throws Exception {
+ final String url = StubDriver.PREFIX + "dropped-inside-the-window";
+ CachedConnection.aliveBypassNanos = TimeUnit.HOURS.toNanos(1);
+ final Connection parent = mock(Connection.class);
+ when(parent.isValid(anyInt())).thenReturn(true);
+ stub.answerWith(parent);
+ CachedConnection.getConnection(url).close();
+
+ when(parent.isValid(anyInt())).thenReturn(false); // the database dropped it where it lay
+ final Connection dropped = CachedConnection.getConnection(url);
+ assertSame(((CachedConnection) dropped).parent, parent, "the pooled connection was not the one handed back");
+ verify(parent, never()).isValid(anyInt()); // handed out on the strength of its last answer
+
+ // the statement of the caller is where the drop surfaces, and the caller reports it
+ CachedConnection.distrustPool(url);
+ dropped.close();
+ final Connection fresh = mock(Connection.class);
+ when(fresh.isValid(anyInt())).thenReturn(true);
+ stub.answerWith(fresh);
+
+ final Connection next = CachedConnection.getConnection(url);
+
+ verify(parent).isValid(CachedConnection.VALIDATION_TIMEOUT_SECONDS);
+ verify(parent).close();
+ assertSame(((CachedConnection) next).parent, fresh, "the rest of the generation was handed out unvalidated");
+ }
+
+ /**
+ * Seeds the pool the way {@link CachedConnection#close()} fills it - at the end a borrow takes
+ * from - so that the connection named first here is the one the next borrow gets.
+ */
+ private static void seedPool(String url, Connection... parents) {
+ for (int i = parents.length - 1; i >= 0; i--) {
+ CachedConnection.cached.get(url).addFirst(new CachedConnection(url, parents[i]));
+ }
+ }
+
+ /**
+ * The borrows nothing compensates a dropped connection on - the open of a backend, the removal
+ * of its files, the start of an import - ask for a connection the pool validates whatever the
+ * window says. Each of them is one borrow of a cold path, and the one that opens a backend
+ * issues no statement at all: a connection dropped inside the window would surface there out of
+ * the rollback that releases it, with no statement to replay and nothing to tell the pool.
+ */
+ @Test(timeOut = 120000)
+ public void testTheBorrowsNothingCompensatesAreValidated() throws Exception {
+ final String url = StubDriver.PREFIX + "validated-borrow";
+ CachedConnection.aliveBypassNanos = TimeUnit.HOURS.toNanos(1);
+ final Connection parent = mock(Connection.class);
+ when(parent.isValid(anyInt())).thenReturn(true);
+ stub.answerWith(parent);
+ CachedConnection.getConnection(url).close();
+
+ final Connection borrowed = CachedConnection.getConnection(url, false);
+
+ assertSame(((CachedConnection) borrowed).parent, parent, "the pooled connection was not the one handed back");
+ verify(parent).isValid(CachedConnection.VALIDATION_TIMEOUT_SECONDS);
+ }
+
+ /**
+ * A connection closed under the borrow is not handed out on the strength of its last answer:
+ * the removal listener of the pool closes every connection it finds in the deque when the pool
+ * expires, and it iterates a weakly consistent view. The validation the window replaces
+ * answered that as well, out of a flag of the driver rather than out of a round trip.
+ */
+ @Test(timeOut = 120000)
+ public void testAConnectionThePoolClosedIsNotHandedOut() throws Exception {
+ final String url = StubDriver.PREFIX + "closed-inside-the-window";
+ CachedConnection.aliveBypassNanos = TimeUnit.HOURS.toNanos(1);
+ final Connection parent = mock(Connection.class);
+ when(parent.isValid(anyInt())).thenReturn(true);
+ stub.answerWith(parent);
+ CachedConnection.getConnection(url).close();
+ // closed where it lay, by the expiry of the pool: a closed connection answers isValid() with
+ // false as well, which is what discards it once the window stops trusting it
+ when(parent.isClosed()).thenReturn(true);
+ when(parent.isValid(anyInt())).thenReturn(false);
+ final Connection fresh = mock(Connection.class);
+ when(fresh.isValid(anyInt())).thenReturn(true);
+ stub.answerWith(fresh);
+
+ final Connection borrowed = CachedConnection.getConnection(url);
+
+ assertSame(((CachedConnection) borrowed).parent, fresh, "a closed connection was handed out on its last answer");
+ }
+
+ /**
+ * The window is clamped twice: to the idle time the pool keeps a connection for, since a window
+ * longer than that is one the pool can never back - the connection it was meant for is gone
+ * before it closes - and to {@link CachedConnection#MAX_ALIVE_BYPASS_MS} behind it, since the
+ * ttl has no upper bound of its own and a value the unit conversion saturates on would leave
+ * every connection of the pool trusted for the life of the server.
+ * <p>
+ * About the value the class settles on at initialization: the field the pool reads is assigned
+ * once, so a ttl set after that changes neither it nor the idle time it was clamped to.
+ */
+ @Test(timeOut = 120000)
+ public void testTheWindowIsClampedToTheIdleTimeOfThePool() {
+ System.setProperty(CachedConnection.TTL_PROPERTY, "15000");
+ System.setProperty(CachedConnection.ALIVE_BYPASS_PROPERTY, "500");
+ assertEquals(CachedConnection.getAliveBypassMillis(), 500L, "a window inside the ttl was not left alone");
+
+ System.setProperty(CachedConnection.ALIVE_BYPASS_PROPERTY, Long.toString(Long.MAX_VALUE));
+ assertEquals(CachedConnection.getAliveBypassMillis(), 15000L, "a window of Long.MAX_VALUE was not clamped");
+
+ System.setProperty(CachedConnection.TTL_PROPERTY, "100");
+ assertEquals(CachedConnection.getAliveBypassMillis(), 100L, "the clamp is the configured ttl, not the default");
+
+ // the ttl has no upper bound of its own, so the clamp to it does not bound the window either: both set
+ // to a value the conversion to nanoseconds saturates on would leave every connection of the pool
+ // trusted for the life of the server, which is the outcome this javadoc says the clamp rules out
+ System.setProperty(CachedConnection.TTL_PROPERTY, Long.toString(Long.MAX_VALUE));
+ System.setProperty(CachedConnection.ALIVE_BYPASS_PROPERTY, Long.toString(Long.MAX_VALUE));
+ assertEquals(CachedConnection.getAliveBypassMillis(), CachedConnection.MAX_ALIVE_BYPASS_MS,
+ "a window the ttl did not bound was left to saturate");
+ }
+
+ /**
+ * A setting worth warning about must leave the class usable. Both properties are read by the
+ * initializer of {@code aliveBypassNanos}, and both report an unusable value through the set of
+ * what has been said once already - which, declared below that initializer, would still be null
+ * when the initializer reaches it (JLS 12.4.2). A window longer than the ttl is exactly the
+ * tuning the javadoc of the property invites, and it would turn a log line into an
+ * ExceptionInInitializerError on the first borrow and a causeless NoClassDefFoundError on every
+ * one after it: no connection can be borrowed, so the backend cannot open at all.
+ * <p>
+ * Asserted on the class loaded afresh rather than on this one, which was initialized long
+ * before the property was set.
+ */
+ @Test(timeOut = 120000, dataProvider = "settingsWorthWarningAbout")
+ public void testASettingWorthWarningAboutStillInitializesTheClass(String ttl, String window, long expectedMillis)
+ throws Exception {
+ System.setProperty(CachedConnection.TTL_PROPERTY, ttl);
+ System.setProperty(CachedConnection.ALIVE_BYPASS_PROPERTY, window);
+
+ final Class<?> reloaded = loadedAfresh(CachedConnection.class);
+
+ assertNotSame(reloaded, CachedConnection.class, "the class under test was not loaded afresh");
+ final Field field = reloaded.getDeclaredField("aliveBypassNanos");
+ field.setAccessible(true);
+ assertEquals(field.getLong(null), TimeUnit.MILLISECONDS.toNanos(expectedMillis),
+ "the window the reloaded class settled on");
+ }
+
+ @DataProvider
+ public Object[][] settingsWorthWarningAbout() {
+ return new Object[][]{
+ // a window longer than the ttl: reported once and used as the ttl
+ {"15000", "60000", 15000L},
+ // not a number, and negative: reported once and ignored in favour of the default
+ {"15000", "half a second", CachedConnection.DEFAULT_ALIVE_BYPASS_MS},
+ {"15000", "-1", CachedConnection.DEFAULT_ALIVE_BYPASS_MS},
+ // the ttl is read by the same initializer, and reports its own value the same way
+ {"30s", "500", 500L}
+ };
+ }
+
+ /**
+ * The class again, defined by a loader of this test rather than taken from the one that has
+ * already initialized it: a static initializer runs once per loader, and this is about what it
+ * does. Every other class is delegated to the parent, so the reloaded one shares the types it
+ * is written against.
+ */
+ private static Class<?> loadedAfresh(Class<?> type) throws Exception {
+ final String name = type.getName();
+ final ClassLoader parent = type.getClassLoader();
+ final ClassLoader loader = new ClassLoader(parent) {
+ @Override
+ protected Class<?> loadClass(String candidate, boolean resolve) throws ClassNotFoundException {
+ if (!name.equals(candidate)) {
+ return super.loadClass(candidate, resolve);
+ }
+ Class<?> defined = findLoadedClass(candidate);
+ if (defined == null) {
+ final byte[] bytecode = bytecodeOf(candidate, parent);
+ defined = defineClass(candidate, bytecode, 0, bytecode.length);
+ }
+ if (resolve) {
+ resolveClass(defined);
+ }
+ return defined;
+ }
+ };
+ return Class.forName(name, true, loader);
+ }
+
+ private static byte[] bytecodeOf(String name, ClassLoader from) throws ClassNotFoundException {
+ try (final InputStream in = from.getResourceAsStream(name.replace('.', '/') + ".class")) {
+ if (in == null) {
+ throw new ClassNotFoundException(name);
+ }
+ final ByteArrayOutputStream bytecode = new ByteArrayOutputStream();
+ final byte[] chunk = new byte[8192];
+ for (int read; (read = in.read(chunk)) >= 0; ) {
+ bytecode.write(chunk, 0, read);
+ }
+ return bytecode.toByteArray();
+ } catch (IOException e) {
+ throw new ClassNotFoundException(name, e);
+ }
+ }
+
private static SQLException tooManyConnections() {
// 53300, too_many_connections, of the insufficient_resources class
return new SQLException("sorry, too many clients already", "53300");
diff --git a/opendj-server-legacy/src/test/java/org/opends/server/backends/jdbc/JDBCStorageRetryTest.java b/opendj-server-legacy/src/test/java/org/opends/server/backends/jdbc/JDBCStorageRetryTest.java
index eac8048..ee1e112 100644
--- a/opendj-server-legacy/src/test/java/org/opends/server/backends/jdbc/JDBCStorageRetryTest.java
+++ b/opendj-server-legacy/src/test/java/org/opends/server/backends/jdbc/JDBCStorageRetryTest.java
@@ -15,25 +15,62 @@
*/
package org.opends.server.backends.jdbc;
+import org.forgerock.opendj.server.config.server.JDBCBackendCfg;
import org.opends.server.DirectoryServerTestCase;
+import org.opends.server.backends.pluggable.spi.AccessMode;
import org.opends.server.backends.pluggable.spi.StorageRuntimeException;
+import org.opends.server.backends.pluggable.spi.TreeName;
+import org.opends.server.backends.pluggable.spi.WriteOperation;
import org.opends.server.types.DirectoryException;
+import org.testng.annotations.AfterClass;
+import org.testng.annotations.BeforeClass;
import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;
+import java.sql.Connection;
+import java.sql.DatabaseMetaData;
+import java.sql.Driver;
+import java.sql.DriverManager;
+import java.sql.DriverPropertyInfo;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
import java.sql.SQLException;
+import java.sql.SQLNonTransientConnectionException;
+import java.sql.SQLRecoverableException;
+import java.sql.Statement;
+import java.util.Properties;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.logging.Logger;
import static org.forgerock.i18n.LocalizableMessage.raw;
import static org.forgerock.opendj.ldap.ResultCode.OTHER;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.anyBoolean;
+import static org.mockito.Mockito.anyInt;
+import static org.mockito.Mockito.anyString;
+import static org.mockito.Mockito.doNothing;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.startsWith;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertFalse;
+import static org.testng.Assert.assertNull;
import static org.testng.Assert.assertTrue;
+import static org.testng.Assert.fail;
/**
- * Tests how a failure is classified as a transaction conflict, which is what decides whether
- * {@link JDBCStorage#write} replays the operation, and how long it waits before it does.
+ * Tests how a failure is classified - as a transaction conflict, or as a connection the database dropped - which
+ * is what decides whether {@link JDBCStorage#write} replays the operation, and how long it waits before it does;
+ * and what {@code write()} itself does with that verdict, replay and pool alike.
* <p>
* Runs without a database: the failures the drivers report are reproduced as synthetic
- * {@link SQLException}s carrying the same vendor error number and SQLState.
+ * {@link SQLException}s carrying the same vendor error number and SQLState, and the writes that carry them run
+ * against mocked connections handed out by a driver of this test.
*/
@Test(sequential = true)
@SuppressWarnings("javadoc")
@@ -45,6 +82,35 @@
private static final String ORACLE = "oracle.jdbc.driver.T4CConnection";
private static final String POSTGRES = "org.postgresql.jdbc.PgConnection";
+ /** The tree every write of this test opens; the table name behind it is a hash of this name. */
+ private static final TreeName TREE = new TreeName("dc=example,dc=com", "id2entry");
+
+ private final StubDriver stub = new StubDriver();
+
+ /** Every test gets a pool of its own: the pools and the distrust of a pool are keyed by the url. */
+ private final AtomicInteger pools = new AtomicInteger();
+
+ /** The statement a create of a test runs, so that a test can assert that it ran - or that it did not. */
+ private PreparedStatement statements;
+
+ /** The connection behind the pool of a test, so that a test can assert the statement it was asked to prepare. */
+ private Connection engineConnection;
+
+ /**
+ * Connections whose class names carry the engine the way the drivers' own do - pgjdbc's
+ * {@code org.postgresql.jdbc.PgConnection}, Connector/J's {@code com.mysql.cj.jdbc.ConnectionImpl}. That name
+ * is what {@code driverNameOf()} matches an engine on, and the name of a mock is derived from the type it
+ * mocks, so a mock of plain {@link Connection} reaches no engine branch of {@code openTree()} at all. Lowercase
+ * because the match is case sensitive.
+ */
+ interface postgresConnection extends Connection
+ {
+ }
+
+ interface mysqlConnection extends Connection
+ {
+ }
+
/** A failure whose cause chain is a cycle, to check that walking it terminates. */
private static final class SelfCausedException extends RuntimeException
{
@@ -115,6 +181,155 @@
assertEquals(JDBCStorage.isRetryableConflict(failure, driver), expected, name);
}
+ @DataProvider
+ public Object[][] connectionFailures()
+ {
+ return new Object[][] {
+ // class 08, connection exception: pgjdbc reports the next use of a connection the server dropped as 08003,
+ // and a socket that failed under it as 08006, while a connect that never came up is 08001
+ { "connection does not exist", sql(0, "08003"), true },
+ { "connection failure", sql(0, "08006"), true },
+ { "unable to establish connection", sql(0, "08001"), true },
+ // the FATAL message a pg_terminate_backend or a shutdown sends before the socket closes: the connection is
+ // gone, and only its next use would be reported as class 08
+ { "admin shutdown", sql(0, "57P01"), true },
+ { "crash shutdown", sql(0, "57P02"), true },
+ { "cannot connect now", sql(0, "57P03"), true },
+ // it reaches write() wrapped, exactly as a conflict does
+ { "wrapped once", new StorageRuntimeException(sql(0, "08006")), true },
+ { "wrapped twice",
+ new DirectoryException(OTHER, raw("unchecked"), new StorageRuntimeException(sql(0, "08003"))), true },
+ { "wrapped 57P0x", new StorageRuntimeException(sql(0, "57P01")), true },
+ // the types the JDBC contract gives a driver to say the connection is gone, whatever state it fills in:
+ // oracle reports ORA-03113 and ORA-01089 as SQLRecoverableException, and only happens to map them to 08006
+ { "recoverable", new SQLRecoverableException("closed connection", "72000", 3113), true },
+ { "non transient connection", new SQLNonTransientConnectionException("socket closed", "S1000", 0), true },
+ // a driver reports what happened as the next exception of a generic failure as readily as it reports it
+ // as the cause, and mssql-jdbc chains every error of a message it received that way
+ { "next exception", chained(sql(0, "HY000"), sql(0, "08006")), true },
+ // the drop of the rollback that releases a connection arrives suppressed into the failure of the operation
+ { "suppressed", suppressing(sql(2627, "23000"), sql(0, "08006")), true },
+
+ // a statement the database answered, however badly, leaves the connection usable
+ { "deadlock victim", sql(1205, "40001"), false },
+ { "primary key violation", sql(2627, "23000"), false },
+ // 53300 is the server refusing a further connection, not the loss of one already established
+ { "too many connections", sql(0, "53300"), false },
+ // a killed session on SQL Server: generateStateCode maps neither 596 nor its siblings, so with xopenStates
+ // off - the default - it arrives as "S"+errorState and no state tells it from a rejected statement. What
+ // does tell it apart is the connection the driver closed behind it, see the test below
+ { "mssql killed session", sql(596, "S0001"), false },
+ { "no SQLState", sql(0, null), false },
+ { "not a SQLException", new IllegalStateException("connection closed"), false },
+ { "no failure at all", null, false },
+ { "cyclic cause chain", new SelfCausedException(), false },
+ };
+ }
+
+ @Test(dataProvider = "connectionFailures")
+ public void testIsConnectionFailure(String name, Throwable failure, boolean expected)
+ {
+ assertEquals(JDBCStorage.isConnectionFailure(failure), expected, name);
+ }
+
+ /**
+ * A connection the database dropped is replayed on a connection the next attempt borrows of its own - but only
+ * while the transaction has not been committed yet. A drop reported by {@code commit()} leaves the outcome of
+ * the transaction unknown, and replaying a write that in fact committed applies it twice.
+ */
+ @Test
+ public void testADroppedConnectionIsReplayedOnlyBeforeTheCommit()
+ {
+ final SQLException dropped = sql(0, "08006");
+ assertEquals(JDBCStorage.replayReason(dropped, POSTGRES, false, false, false),
+ "a connection the database dropped");
+ assertNull(JDBCStorage.replayReason(dropped, POSTGRES, true, false, false),
+ "an in doubt transaction was replayed");
+ }
+
+ /**
+ * A driver that closed the connection has said the connection is gone whatever SQLState it filled in - which is
+ * the only way a killed SQL Server session is ever recognized, since it arrives as S0001.
+ */
+ @Test
+ public void testAConnectionTheDriverClosedIsADroppedOne()
+ {
+ final SQLException killed = sql(596, "S0001");
+ assertNull(JDBCStorage.replayReason(killed, MSSQL, false, false, false), "S0001 was replayed on its own");
+ assertEquals(JDBCStorage.replayReason(killed, MSSQL, false, false, true),
+ "a connection the database dropped");
+ assertNull(JDBCStorage.replayReason(killed, MSSQL, true, false, true),
+ "an in doubt transaction was replayed");
+ }
+
+ /**
+ * An attempt that committed part of its own work is not replayed, whatever the failure says: what it did no
+ * longer rolls back as a whole, and a WriteOperation is only idempotent in the database. RootContainer.open
+ * opens and registers the entry containers of every base DN in one write, and a replay of it fails with
+ * ERR_ENTRY_CONTAINER_ALREADY_REGISTERED, masking the failure that caused the replay.
+ */
+ @Test
+ public void testAnAttemptThatCommittedPartOfItsWorkIsNotReplayed()
+ {
+ assertNull(JDBCStorage.replayReason(sql(0, "40001"), POSTGRES, false, true, false), "a conflict was replayed");
+ assertNull(JDBCStorage.replayReason(sql(0, "08006"), POSTGRES, false, true, false), "a drop was replayed");
+ assertNull(JDBCStorage.replayReason(sql(596, "S0001"), MSSQL, false, true, true), "a drop was replayed");
+ }
+
+ /**
+ * A conflict is replayed on the strength of the engine having rolled the transaction back before it answered,
+ * so it is read from the failure of the operation and not from the release of the connection: a class 40 the
+ * release contributed - Oracle reports a transaction rolled back under it as ORA-02091, SQLState 40000 - would
+ * otherwise re-authorise the replay of a commit whose outcome is unknown, past the guard that exists for it.
+ * A drop is read from the release as well, which is the one place it is often stated at all.
+ */
+ @Test
+ public void testAConflictIsNotReadFromTheReleaseOfTheConnection()
+ {
+ final SQLException onRelease = suppressing(sql(2627, "23000"), sql(0, "40000"));
+ assertFalse(JDBCStorage.isRetryableConflict(onRelease, POSTGRES), "a conflict was read from the release");
+ assertNull(JDBCStorage.replayReason(onRelease, POSTGRES, true, false, false),
+ "a transaction the commit left in doubt was replayed");
+
+ // the same shape carrying a drop instead: read, since the release is where a drop is stated at all
+ assertTrue(JDBCStorage.isConnectionFailure(suppressing(sql(2627, "23000"), sql(0, "08006"))),
+ "a drop was not read from the release");
+ }
+
+ /** The connection is asked only where a state does not already say the connection is gone. */
+ @Test
+ public void testTheConnectionIsAskedWhetherTheDriverClosedIt() throws Exception
+ {
+ final Connection closed = mock(Connection.class);
+ when(closed.isClosed()).thenReturn(true);
+ final Connection alive = mock(Connection.class);
+ when(alive.isClosed()).thenReturn(false);
+ final Connection mute = mock(Connection.class);
+ when(mute.isClosed()).thenThrow(new SQLException("the connection cannot say"));
+
+ assertTrue(JDBCStorage.isConnectionFailure(sql(596, "S0001"), closed), "a killed session was not recognized");
+ assertFalse(JDBCStorage.isConnectionFailure(sql(2627, "23000"), alive), "a rejected statement was a drop");
+ assertTrue(JDBCStorage.isConnectionFailure(sql(0, "08006"), alive), "class 08 needs no connection to say so");
+ assertTrue(JDBCStorage.isConnectionFailure(sql(2627, "23000"), mute), "a connection that cannot answer");
+ }
+
+ /** A conflict is a rollback the engine completed before it answered, whichever phase reported it. */
+ @Test
+ public void testAConflictIsReplayedFromEitherPhase()
+ {
+ final SQLException conflict = sql(0, "40001");
+ assertEquals(JDBCStorage.replayReason(conflict, POSTGRES, false, false, false), "a conflict");
+ assertEquals(JDBCStorage.replayReason(conflict, POSTGRES, true, false, false), "a conflict");
+ }
+
+ /** Everything else fails the operation, as it did before either replay existed. */
+ @Test
+ public void testAFailureOfTheStatementIsNotReplayed()
+ {
+ assertNull(JDBCStorage.replayReason(sql(2627, "23000"), MSSQL, false, false, false));
+ assertNull(JDBCStorage.replayReason(sql(2627, "23000"), MSSQL, true, false, false));
+ }
+
/** The delay grows with the attempt, so that the replays outlast a contention lasting more than a few ms. */
@Test
public void testRetryDelayGrowsAndStaysBounded()
@@ -143,23 +358,575 @@
public void testConflictSummaryNamesTheStateAndTheNumber()
{
final String summary = JDBCStorage.conflictSummary(
- new DirectoryException(OTHER, raw("unchecked"), new StorageRuntimeException(sql(1205, "40001"))));
+ new DirectoryException(OTHER, raw("unchecked"), new StorageRuntimeException(sql(1205, "40001"))), POSTGRES);
assertTrue(summary.contains("40001"), summary);
assertTrue(summary.contains("1205"), summary);
assertTrue(summary.contains("synthetic failure"), summary);
}
+ /**
+ * That line is the only record a replay leaves, so it names the failure the replay was decided on. A write whose
+ * operation was rejected and whose release then reported a drop is replayed on the class 08 suppressed into the
+ * rejection, and naming the state of the rejected statement would describe a replay that did not happen.
+ */
+ @Test
+ public void testConflictSummaryNamesTheFailureTheReplayWasDecidedOn()
+ {
+ final String summary = JDBCStorage.conflictSummary(
+ new StorageRuntimeException(suppressing(sql(2627, "23000"), sql(0, "08006"))), POSTGRES);
+ assertTrue(summary.contains("08006"), summary);
+ assertFalse(summary.contains("23000"), summary);
+ }
+
/** A failure carrying no SQLException at all, and a cyclic cause chain, still have to yield something loggable. */
@Test
public void testConflictSummaryTerminatesWithoutASQLException()
{
- assertTrue(JDBCStorage.conflictSummary(new IllegalStateException("connection closed")).contains("closed"));
- assertTrue(JDBCStorage.conflictSummary(new SelfCausedException()).contains("SelfCausedException"));
- assertEquals(JDBCStorage.conflictSummary(null), "null");
+ assertTrue(JDBCStorage.conflictSummary(new IllegalStateException("connection closed"), POSTGRES).contains("closed"));
+ assertTrue(JDBCStorage.conflictSummary(new SelfCausedException(), POSTGRES).contains("SelfCausedException"));
+ assertEquals(JDBCStorage.conflictSummary(null, POSTGRES), "null");
+ }
+
+ /** A statement that carries neither a conflict nor a drop is still the one the summary names. */
+ @Test
+ public void testConflictSummaryFallsBackToTheFirstFailureOfTheChain()
+ {
+ final String summary = JDBCStorage.conflictSummary(new StorageRuntimeException(sql(2627, "23000")), POSTGRES);
+ assertTrue(summary.contains("23000"), summary);
+
+ // the fallback names the statement, not the rollback of the release behind it: this is where a replay
+ // decided on the closed flag of the connection alone lands - neither chain carries a verdict of its own -
+ // and the walk reaches the suppressed exceptions of a failure before its cause
+ final StorageRuntimeException killedSession = new StorageRuntimeException(sql(596, "S0001"));
+ killedSession.addSuppressed(sql(0, "25P02"));
+ final String decidedOnTheConnection = JDBCStorage.conflictSummary(killedSession, MSSQL);
+ assertTrue(decidedOnTheConnection.contains("S0001"), decidedOnTheConnection);
+ assertFalse(decidedOnTheConnection.contains("25P02"), decidedOnTheConnection);
+ }
+
+ /**
+ * The walk of a failure looks at a bounded number of links: mssql-jdbc chains every error of one message it
+ * received through {@code setNextException}, and a budget spent on those would never reach the cause a wrapper
+ * carries. Pinned from both sides - a drop on the last link of the budget is found and one link further is not
+ * - since a number nothing pins drifts unnoticed in either direction.
+ */
+ @Test
+ public void testTheWalkOfAFailureStopsAtItsBudget()
+ {
+ assertTrue(JDBCStorage.isConnectionFailure(chainEndingInADrop(64)), "a drop on the last link of the budget");
+ assertFalse(JDBCStorage.isConnectionFailure(chainEndingInADrop(65)), "a drop past the budget was walked to");
+ }
+
+ /**
+ * Opening a tree that is already there commits nothing, so the attempt stays replayable. The create table is
+ * guarded by a catalog read, and so is the create index on every engine but postgresql, so on an existing
+ * backend {@code openTree(name, true)} issues no statement at all - while
+ * {@code RootContainer.open()} opens every tree of every base DN in a single write whose first act is one of
+ * these. A flag raised on the catalog read alone would leave that write unreplayable for the life of the
+ * backend, the conflict replay of #867 included: {@code replayReason()} reads the flag before anything else.
+ */
+ @Test
+ public void testOpeningAnExistingTreeLeavesTheAttemptReplayable() throws Exception
+ {
+ final JDBCStorage storage = storageOverACatalogHolding(true);
+ final AtomicInteger attempts = new AtomicInteger();
+
+ storage.write(txn -> {
+ txn.openTree(TREE, true);
+ if (attempts.incrementAndGet() == 1)
+ {
+ throw new StorageRuntimeException(sql(0, "40001"));
+ }
+ });
+
+ assertEquals(attempts.get(), 2, "a transaction that committed nothing was not replayed");
+ verify(statements, never()).executeUpdate();
+ }
+
+ /**
+ * A tree that had to be created did commit - the create table commits, and mysql and oracle commit before a DDL
+ * statement of their own accord - so the attempt is out of the replay whatever the failure says: a
+ * {@link WriteOperation} is only idempotent in the database, and {@code RootContainer.open()} replayed after the
+ * trees of the first base DN were created registers that base DN a second time.
+ */
+ @Test
+ public void testCreatingATreeTakesTheAttemptOutOfTheReplay() throws Exception
+ {
+ final JDBCStorage storage = storageOverACatalogHolding(false);
+ final AtomicInteger attempts = new AtomicInteger();
+
+ try
+ {
+ storage.write(txn -> {
+ txn.openTree(TREE, true);
+ attempts.incrementAndGet();
+ throw new StorageRuntimeException(sql(0, "40001"));
+ });
+ fail("a transaction that had committed a create table was replayed");
+ }
+ catch (StorageRuntimeException expected)
+ {
+ assertTrue(JDBCStorage.isRetryableConflict(expected, POSTGRES), "the conflict was not the failure raised");
+ }
+ assertEquals(attempts.get(), 1, "a transaction that committed part of its work was replayed");
+ verify(statements).executeUpdate();
+ }
+
+ /**
+ * The rollback that unwinds a failed attempt is often the first place a drop is stated outright, and on a
+ * driver that reports a killed session as a plain vendor error it is the only one. It is joined to the failure
+ * being unwound rather than dropped on the floor, so that the classifiers below read it: without it the attempt
+ * would lean on the driver having flipped its closed flag already, and a driver that has not gives neither the
+ * replay nor the distrust.
+ */
+ @Test
+ public void testTheRollbackOfAFailedAttemptIsNotSwallowed() throws Exception
+ {
+ final long window = CachedConnection.aliveBypassNanos;
+ CachedConnection.aliveBypassNanos = TimeUnit.HOURS.toNanos(1);
+ try
+ {
+ final Connection pooled = mock(Connection.class);
+ when(pooled.isValid(anyInt())).thenReturn(true);
+ final Connection dropped = mock(Connection.class);
+ when(dropped.isValid(anyInt())).thenReturn(true);
+ when(dropped.isClosed()).thenReturn(false); // the driver has not flipped its flag yet
+
+ final JDBCStorage storage = storageOver(pooled, dropped);
+ final Connection first = storage.getConnection();
+ final Connection second = storage.getConnection();
+ first.close();
+ second.close();
+ // proven alive by the connect itself, and inside the window ever since: nothing has validated
+ verify(dropped, never()).isValid(anyInt());
+
+ // only the rollback that unwinds the attempt says the connection is gone: the release behind it
+ // goes through, so the dropped connection is back at the head of the pool - where the replay
+ // borrows it again - with nothing else to report what it saw
+ doThrow(new SQLException("connection reset", "08006")).doNothing().when(dropped).rollback();
+
+ final AtomicInteger attempts = new AtomicInteger();
+ storage.write(txn -> {
+ if (attempts.incrementAndGet() == 1)
+ {
+ throw new StorageRuntimeException(sql(596, "S0001")); // a killed session, as mssql-jdbc reports it
+ }
+ });
+
+ assertEquals(attempts.get(), 2, "the drop the rollback reported was not replayed");
+ // the distrust reached the pool: the borrow of the replay validated instead of trusting the
+ // last answer of a connection that predates the drop
+ verify(dropped, times(1)).isValid(CachedConnection.VALIDATION_TIMEOUT_SECONDS);
+ }
+ finally
+ {
+ CachedConnection.aliveBypassNanos = window;
+ }
+ }
+
+ /**
+ * A drop the release of the connection reported reaches the pool as well as the replay. It is suppressed into
+ * the failure of the operation (JLS 14.20.3.1) rather than replacing it, so the attempt sees it only on the
+ * chains of that failure - and the pool has no other way of hearing of it: the rest of that generation would
+ * otherwise be handed out unvalidated one by one until the pool runs out of it.
+ */
+ @Test
+ public void testADropReportedByTheReleaseReachesThePool() throws Exception
+ {
+ final long window = CachedConnection.aliveBypassNanos;
+ CachedConnection.aliveBypassNanos = TimeUnit.HOURS.toNanos(1);
+ try
+ {
+ final Connection pooled = mock(Connection.class);
+ when(pooled.isValid(anyInt())).thenReturn(true);
+ final Connection released = mock(Connection.class);
+ when(released.isValid(anyInt())).thenReturn(true);
+
+ final JDBCStorage storage = storageOver(pooled, released);
+ // both are proven alive and back in the pool; the one released last is the one the write borrows
+ final Connection first = storage.getConnection();
+ final Connection second = storage.getConnection();
+ first.close();
+ second.close();
+
+ // from here the database has dropped the connection at the head of the pool: the operation is
+ // rejected for its own reasons, the rollback that unwinds the attempt goes through, and the release
+ // behind it is where the drop surfaces. Chained, so that the drop lands on the second rollback: an
+ // unchained stub fails the first one - the rollback of the attempt - and pins the sibling test above
+ doNothing().doThrow(new SQLException("connection reset", "08006")).when(released).rollback();
+
+ final AtomicInteger attempts = new AtomicInteger();
+ storage.write(txn -> {
+ if (attempts.incrementAndGet() == 1)
+ {
+ throw new StorageRuntimeException(sql(2627, "23000"));
+ }
+ });
+
+ assertEquals(attempts.get(), 2, "the drop suppressed into the failure was not replayed");
+ // the return to the pool that seeded it, the rollback of the attempt, and the release behind it - which
+ // is the one that reported, since the stub above lets the rollback of the attempt through
+ verify(released, times(3)).rollback();
+ // the distrust reached the pool from the release: the borrow of the replay validated instead of
+ // trusting the last answer of a connection established before the drop
+ verify(pooled).isValid(CachedConnection.VALIDATION_TIMEOUT_SECONDS);
+ }
+ finally
+ {
+ CachedConnection.aliveBypassNanos = window;
+ }
+ }
+
+ /**
+ * A read is never replayed - two of the read operations of this server are not idempotent - but a drop it ran
+ * into still has to reach the pool, which has no other way of hearing of one: a borrow inside the window asks
+ * the database nothing, so the statement that broke is the only place the drop is ever seen. The release of
+ * the connection counts as such a statement: its rollback is the one round trip a read that found nothing
+ * makes.
+ */
+ @Test
+ public void testADropAReadRanIntoReachesThePool() throws Exception
+ {
+ final long window = CachedConnection.aliveBypassNanos;
+ CachedConnection.aliveBypassNanos = TimeUnit.HOURS.toNanos(1);
+ try
+ {
+ final Connection pooled = mock(Connection.class);
+ when(pooled.isValid(anyInt())).thenReturn(true);
+ final Connection released = mock(Connection.class);
+ when(released.isValid(anyInt())).thenReturn(true);
+
+ final JDBCStorage storage = storageOver(pooled, released);
+ final Connection first = storage.getConnection();
+ final Connection second = storage.getConnection();
+ first.close();
+ second.close();
+ // both are proven alive and inside the window: nothing has validated
+ verify(released, never()).isValid(anyInt());
+
+ // the read is rejected for its own reasons, and the release behind it - a read issues no rollback of its
+ // own - is where the connection the database dropped says so
+ doThrow(new SQLException("connection reset", "08006")).when(released).rollback();
+ try
+ {
+ storage.read(txn -> {
+ throw new StorageRuntimeException(sql(2627, "23000"));
+ });
+ fail("the failure of the read was swallowed");
+ }
+ catch (StorageRuntimeException expected)
+ {
+ assertTrue(JDBCStorage.isConnectionFailure(expected), "the drop of the release did not reach the failure");
+ }
+
+ storage.getConnection().close(); // the borrow that follows it validates instead of trusting
+
+ verify(pooled).isValid(CachedConnection.VALIDATION_TIMEOUT_SECONDS);
+ }
+ finally
+ {
+ CachedConnection.aliveBypassNanos = window;
+ }
+ }
+
+ /**
+ * The create index of the postgres branch is asked of the catalog first, although postgresql has "create index
+ * if not exists": that statement commits whether it creates anything or not, and unguarded it would take every
+ * write that opens a tree out of the replay - {@code RootContainer.open()} and its ~25 trees per suffix
+ * included.
+ */
+ @Test
+ public void testThePostgresIndexIsAskedOfTheCatalogBeforeItIsCreated() throws Exception
+ {
+ final JDBCStorage storage = storageOverAnEngine(postgresConnection.class, true);
+ final AtomicInteger attempts = new AtomicInteger();
+
+ storage.write(txn -> {
+ txn.openTree(TREE, true);
+ if (attempts.incrementAndGet() == 1)
+ {
+ throw new StorageRuntimeException(sql(0, "40001"));
+ }
+ });
+
+ assertEquals(attempts.get(), 2, "a transaction that committed nothing was not replayed");
+ verify(statements, never()).executeUpdate();
+ }
+
+ /**
+ * postgresql runs DDL inside the transaction, so a create index the engine rolled back has committed nothing:
+ * {@code write()} rolls the attempt back whole and replays it. Raising the flag in front of the statement -
+ * which is what mysql and oracle need, since they commit before a DDL of their own accord - would turn a
+ * deadlock the engine itself undid into a hard failure of the open.
+ */
+ @Test
+ public void testACreateIndexPostgresRolledBackLeavesTheAttemptReplayable() throws Exception
+ {
+ final JDBCStorage storage = storageOverAnEngine(postgresConnection.class, false);
+ when(statements.executeUpdate()).thenThrow(sql(0, "40P01")).thenReturn(0);
+ final AtomicInteger attempts = new AtomicInteger();
+
+ storage.write(txn -> {
+ attempts.incrementAndGet();
+ txn.openTree(TREE, true);
+ });
+
+ assertEquals(attempts.get(), 2, "a create index the engine rolled back was not replayed");
+ verify(engineConnection, times(2)).prepareStatement(startsWith("create index if not exists k_"));
+ }
+
+ /**
+ * mysql commits before a DDL statement whether asked to or not, so a create index that failed there has
+ * committed everything the transaction did before it just as surely as one that succeeded: the attempt is out
+ * of the replay whatever the failure says.
+ */
+ @Test
+ public void testACreateIndexMysqlCommittedBeforeTakesTheAttemptOutOfTheReplay() throws Exception
+ {
+ final JDBCStorage storage = storageOverAnEngine(mysqlConnection.class, false);
+ when(statements.executeUpdate()).thenThrow(sql(1213, "40001"));
+ final AtomicInteger attempts = new AtomicInteger();
+
+ try
+ {
+ storage.write(txn -> {
+ attempts.incrementAndGet();
+ txn.openTree(TREE, true);
+ });
+ fail("a transaction whose create index had committed before it was replayed");
+ }
+ catch (StorageRuntimeException expected)
+ {
+ assertTrue(JDBCStorage.isRetryableConflict(expected, MYSQL), "the conflict was not the failure raised");
+ }
+ assertEquals(attempts.get(), 1, "an attempt that committed part of its work was replayed");
+ verify(engineConnection).prepareStatement(startsWith("create index k_"));
+ }
+
+ /**
+ * The connection the tree names are stamped on is closed as the attempt is unwound, and an unchecked throw out
+ * of a driver's {@code close()} there would replace the exception being unwound (JLS 14.20.2) - the very one
+ * the replay is decided on, and the only one that says what went wrong. The stamp is a diagnostic aid: it is
+ * joined to the failure instead, and the replay goes ahead.
+ */
+ @Test
+ public void testAFailingCommentConnectionDoesNotReplaceTheFailureOfTheWrite() throws Exception
+ {
+ final Connection stamp = mock(Connection.class);
+ when(stamp.createStatement()).thenReturn(mock(Statement.class)); // the lock bound of the stamp session
+ // the readback of the stored comment fails, so the stamp is given up on - with its connection open
+ when(stamp.prepareStatement(anyString())).thenThrow(new SQLException("no readback in this test", "42000"));
+ doThrow(new IllegalStateException("the driver threw out of close()")).when(stamp).close();
+ final JDBCStorage storage = storageOverAnEngine(postgresConnection.class, true, stamp);
+ final AtomicInteger attempts = new AtomicInteger();
+
+ storage.write(txn -> {
+ txn.openTree(TREE, true); // opens the stamp session, which is closed as this attempt is unwound
+ if (attempts.incrementAndGet() == 1)
+ {
+ throw new StorageRuntimeException(sql(0, "40001"));
+ }
+ });
+
+ assertEquals(attempts.get(), 2, "the failure of the comment connection replaced the conflict being unwound");
+ verify(stamp).close();
+ }
+
+ @BeforeClass
+ public void registerStubDriver() throws Exception
+ {
+ DriverManager.registerDriver(stub);
+ }
+
+ @AfterClass
+ public void deregisterStubDriver() throws Exception
+ {
+ DriverManager.deregisterDriver(stub);
+ }
+
+ /**
+ * A storage whose pool hands out one connection of this test, over a catalog that either holds the table of
+ * {@link #TREE} or does not. The connection is a mock of no recognized driver, which is how the engines that
+ * guard their create index - and mssql, which has none - reach {@code openTree}.
+ */
+ private JDBCStorage storageOverACatalogHolding(boolean theTable) throws Exception
+ {
+ final Connection con = mock(Connection.class);
+ final JDBCStorage storage = storageOver(con);
+
+ statements = mock(PreparedStatement.class);
+ final String tableName = storage.getTableName(TREE);
+ final DatabaseMetaData metaData = mock(DatabaseMetaData.class);
+ // a result set of its own per call: the catalog is asked once per attempt, and a replayed attempt
+ // reading a result set the previous one had already walked to its end would find no table there
+ when(metaData.getTables(any(), any(), any(), any())).thenAnswer(invocation -> {
+ final ResultSet tables = mock(ResultSet.class);
+ when(tables.next()).thenReturn(theTable, false);
+ when(tables.getString("TABLE_NAME")).thenReturn(tableName);
+ return tables;
+ });
+
+ when(con.isValid(anyInt())).thenReturn(true);
+ when(con.getMetaData()).thenReturn(metaData);
+ when(con.prepareStatement(anyString())).thenReturn(statements);
+ return storage;
+ }
+
+ /**
+ * A storage whose pool hands out one connection of the given engine, over a catalog holding the table of
+ * {@link #TREE} and either holding its {@code k_} index or not. The index guard and the statement behind it
+ * are the branches {@code openTree()} takes per engine, and a mock of plain {@link Connection} reaches none
+ * of them - so the name the mock ends up with is asserted here rather than assumed.
+ */
+ private JDBCStorage storageOverAnEngine(Class<? extends Connection> engine, boolean theIndex,
+ Connection... behind) throws Exception
+ {
+ final Connection con = mock(engine);
+ final String engineName = engine.getSimpleName().replace("Connection", "");
+ assertTrue(JDBCStorage.driverNameOf(con).contains(engineName),
+ "a mock of " + engine.getSimpleName() + " reaches no " + engineName + " branch: "
+ + JDBCStorage.driverNameOf(con));
+ engineConnection = con;
+ // the connections behind it answer the connects the pool does not make: the stamp of a tree name opens one
+ // of its own, straight through the driver, since the caller of openTree() is holding a pooled connection
+ final Connection[] answers = new Connection[behind.length + 1];
+ answers[0] = con;
+ System.arraycopy(behind, 0, answers, 1, behind.length);
+ final JDBCStorage storage = storageOver(answers);
+
+ statements = mock(PreparedStatement.class);
+ final String tableName = storage.getTableName(TREE);
+ final DatabaseMetaData metaData = mock(DatabaseMetaData.class);
+ // a result set of its own per call, for the reason the catalog of the test above hands out one: a replayed
+ // attempt reading a result set the previous one had already walked to its end would find nothing there
+ when(metaData.getTables(any(), any(), any(), any())).thenAnswer(invocation -> {
+ final ResultSet tables = mock(ResultSet.class);
+ when(tables.next()).thenReturn(true, false);
+ when(tables.getString("TABLE_NAME")).thenReturn(tableName);
+ return tables;
+ });
+ when(metaData.getIndexInfo(any(), any(), any(), anyBoolean(), anyBoolean())).thenAnswer(invocation -> {
+ final ResultSet indexes = mock(ResultSet.class);
+ when(indexes.next()).thenReturn(theIndex, false);
+ when(indexes.getString("INDEX_NAME")).thenReturn("k_" + tableName.substring("opendj_".length()));
+ return indexes;
+ });
+
+ when(con.isValid(anyInt())).thenReturn(true);
+ when(con.getMetaData()).thenReturn(metaData);
+ when(con.prepareStatement(anyString())).thenReturn(statements);
+ // the tree name the sweep stamps the table with runs on a connection of its own and is a diagnostic aid: a
+ // failure of it only logs, and this fixture is about the index statement rather than about the comment
+ when(con.createStatement()).thenThrow(new SQLException("no session statement in this test", "42000"));
+ return storage;
+ }
+
+ /**
+ * A storage of a pool of its own, which connects to the given connections in turn and answers every connect
+ * beyond them with the last. Every test gets a url of its own: both the pools and the distrust of a pool are
+ * keyed by the connection string, so a shared one would carry the state of one test into the next.
+ */
+ private JDBCStorage storageOver(Connection... connections) throws Exception
+ {
+ final JDBCBackendCfg cfg = mock(JDBCBackendCfg.class);
+ when(cfg.getDBDirectory()).thenReturn(StubDriver.PREFIX + pools.incrementAndGet());
+ final JDBCStorage storage = new JDBCStorage(cfg, null);
+ storage.accessMode = AccessMode.READ_WRITE;
+ stub.answerWith(connections);
+ return storage;
+ }
+
+ /** A driver of this test, so that the pool the write borrows from needs no database behind it. */
+ private static final class StubDriver implements Driver
+ {
+ static final String PREFIX = "jdbc:opendj-retry-stub:";
+
+ private volatile Connection[] answers = new Connection[0];
+ private final AtomicInteger connects = new AtomicInteger();
+
+ void answerWith(Connection... answers)
+ {
+ this.answers = answers;
+ this.connects.set(0);
+ }
+
+ @Override
+ public Connection connect(String url, Properties info)
+ {
+ if (!acceptsURL(url) || answers.length == 0)
+ {
+ return null;
+ }
+ // the last one answers every connect beyond the ones named, so a pool that opens more than the
+ // test set up gets a working connection rather than a null the driver contract reads as "not mine"
+ return answers[Math.min(connects.getAndIncrement(), answers.length - 1)];
+ }
+
+ @Override
+ public boolean acceptsURL(String url)
+ {
+ return url != null && url.startsWith(PREFIX);
+ }
+
+ @Override
+ public DriverPropertyInfo[] getPropertyInfo(String url, Properties info)
+ {
+ return new DriverPropertyInfo[0];
+ }
+
+ @Override
+ public int getMajorVersion()
+ {
+ return 1;
+ }
+
+ @Override
+ public int getMinorVersion()
+ {
+ return 0;
+ }
+
+ @Override
+ public boolean jdbcCompliant()
+ {
+ return false;
+ }
+
+ @Override
+ public Logger getParentLogger()
+ {
+ return Logger.getLogger(StubDriver.class.getName());
+ }
}
private static SQLException sql(int errorCode, String sqlState)
{
return new SQLException("synthetic failure", sqlState, errorCode);
}
+
+ /** The second failure as the next exception of the first, the way a driver chains the errors of one message. */
+ private static SQLException chained(SQLException first, SQLException next)
+ {
+ first.setNextException(next);
+ return first;
+ }
+
+ /** A chain of the given number of next exceptions whose last link is a connection that broke. */
+ private static SQLException chainEndingInADrop(int links)
+ {
+ final SQLException head = sql(2627, "23000");
+ SQLException tail = head;
+ for (int link = 2; link <= links; link++)
+ {
+ tail = chained(tail, sql(0, link == links ? "08006" : "23000")).getNextException();
+ }
+ return head;
+ }
+
+ /** The second failure suppressed into the first, the way a failing close() joins the failure of an operation. */
+ private static SQLException suppressing(SQLException failure, SQLException onRelease)
+ {
+ failure.addSuppressed(onRelease);
+ return failure;
+ }
}
diff --git a/opendj-server-legacy/src/test/java/org/opends/server/backends/jdbc/StampConnectionTestCase.java b/opendj-server-legacy/src/test/java/org/opends/server/backends/jdbc/StampConnectionTestCase.java
index 05b055e..25c5c14 100644
--- a/opendj-server-legacy/src/test/java/org/opends/server/backends/jdbc/StampConnectionTestCase.java
+++ b/opendj-server-legacy/src/test/java/org/opends/server/backends/jdbc/StampConnectionTestCase.java
@@ -214,12 +214,13 @@
/**
* A driver reports the vendor error of a failed statement as the next exception of a generic
- * one at least as often as it reports it as the cause. Reading only the cause chain classifies
- * a lock timeout as a rejection, which leaves the tree unstamped until the next start over a
- * moment of contention.
+ * one at least as often as it reports it as the cause, and the statement of a try-with-resources
+ * carries what its {@code close()} saw as a suppressed exception. Reading fewer chains than the
+ * classifiers of a write read classifies a lock timeout - or a connection that broke - as a
+ * rejection, which leaves the tree unstamped for the life of the backend.
*/
@Test
- public void testFailureScopeWalksBothChains() {
+ public void testFailureScopeWalksEveryChain() {
final SQLException reportedAsTheCause = new SQLException("statement failed",
new SQLException("lock wait timeout exceeded", "HY000", 1205));
assertEquals(JDBCStorage.failureScope(reportedAsTheCause, JDBCStorage.Dialect.MYSQL),
@@ -236,6 +237,13 @@
assertEquals(JDBCStorage.failureScope(connectionGone, JDBCStorage.Dialect.MYSQL),
JDBCStorage.FailureScope.SESSION, "a connection exception on the next-exception chain was missed");
+ // the close() of the statement is where a connection that broke under a stamp is often the
+ // only witness, and it joins the failure being unwound as a suppressed exception (JLS 14.20.3.1)
+ final SQLException reportedByTheClose = new SQLException("statement failed");
+ reportedByTheClose.addSuppressed(new SQLException("connection closed", "08006"));
+ assertEquals(JDBCStorage.failureScope(reportedByTheClose, JDBCStorage.Dialect.MYSQL),
+ JDBCStorage.FailureScope.SESSION, "a connection exception suppressed into the failure was missed");
+
// a driver that chains an exception back to itself must not make the walk loop
final SQLException selfReferring = new SQLException("statement failed");
selfReferring.setNextException(selfReferring);
--
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