From d6a5316c7055055f2da0310748dc5a46dc777144 Mon Sep 17 00:00:00 2001
From: Valery Kharseko <vharseko@3a-systems.ru>
Date: Wed, 19 Aug 2026 08:37:49 +0000
Subject: [PATCH] [#870] Stop replaying a rolled back read in the PersistIt backend (#871)
---
opendj-server-legacy/src/main/java/org/opends/server/backends/pdb/PDBStorage.java | 43 ++++++++++++++++++++++---------------------
opendj-server-legacy/src/main/java/org/opends/server/backends/pluggable/spi/ReadOperation.java | 5 +++++
opendj-server-legacy/src/main/java/org/opends/server/backends/pluggable/spi/Storage.java | 7 +++++--
3 files changed, 32 insertions(+), 23 deletions(-)
diff --git a/opendj-server-legacy/src/main/java/org/opends/server/backends/pdb/PDBStorage.java b/opendj-server-legacy/src/main/java/org/opends/server/backends/pdb/PDBStorage.java
index a4e6f97..ea23395 100644
--- a/opendj-server-legacy/src/main/java/org/opends/server/backends/pdb/PDBStorage.java
+++ b/opendj-server-legacy/src/main/java/org/opends/server/backends/pdb/PDBStorage.java
@@ -598,29 +598,30 @@
@Override
public <T> T read(ReadOperation<T> operation) throws Exception
{
+ /*
+ * A rolled back read is not replayed. Unlike WriteOperation, a ReadOperation is not required to be
+ * idempotent, and four of them are not: ExportJob has written entries to its LDIF stream, whose writer is
+ * opened once so that a replay appends rather than truncates; VerifyJob has accumulated its counters in
+ * instance fields that no attempt resets; and the two reads of BackendStat have printed records and
+ * appended to a map owned by their caller. Replaying corrupts their result rather than repairing it, so
+ * the failure goes to the caller, as it does in the JE, Cassandra and JDBC backends.
+ */
final Transaction txn = db.getTransaction();
- for (;;)
+ txn.begin();
+ try
{
- txn.begin();
- try
- {
- final T result = operation.run(this);
- txn.commit(commitPolicy);
- return result;
- }
- catch (final RollbackException e)
- {
- // retry
- }
- catch (final Exception e)
- {
- txn.rollback();
- throw e;
- }
- finally
- {
- txn.end();
- }
+ final T result = operation.run(this);
+ txn.commit(commitPolicy);
+ return result;
+ }
+ catch (final Exception e)
+ {
+ txn.rollback();
+ throw e;
+ }
+ finally
+ {
+ txn.end();
}
}
diff --git a/opendj-server-legacy/src/main/java/org/opends/server/backends/pluggable/spi/ReadOperation.java b/opendj-server-legacy/src/main/java/org/opends/server/backends/pluggable/spi/ReadOperation.java
index 5f2e58b..891eeb1 100644
--- a/opendj-server-legacy/src/main/java/org/opends/server/backends/pluggable/spi/ReadOperation.java
+++ b/opendj-server-legacy/src/main/java/org/opends/server/backends/pluggable/spi/ReadOperation.java
@@ -12,6 +12,7 @@
* information: "Portions Copyright [year] [name of copyright owner]".
*
* Copyright 2014-2015 ForgeRock AS.
+ * Portions Copyright 2026 3A Systems, LLC.
*/
package org.opends.server.backends.pluggable.spi;
@@ -26,6 +27,10 @@
{
/**
* Executes a read operation, and returns the read value.
+ * <p>
+ * Implementations need not be idempotent: unlike {@link WriteOperation}, a read operation is never replayed by
+ * {@link Storage#read(ReadOperation)}, so it is free to print, to write to a stream, or to accumulate state
+ * outside of the transaction.
*
* @param txn
* the read transaction where to execute the read operation
diff --git a/opendj-server-legacy/src/main/java/org/opends/server/backends/pluggable/spi/Storage.java b/opendj-server-legacy/src/main/java/org/opends/server/backends/pluggable/spi/Storage.java
index 179c073..cf04069 100644
--- a/opendj-server-legacy/src/main/java/org/opends/server/backends/pluggable/spi/Storage.java
+++ b/opendj-server-legacy/src/main/java/org/opends/server/backends/pluggable/spi/Storage.java
@@ -12,6 +12,7 @@
* information: "Portions Copyright [year] [name of copyright owner]".
*
* Copyright 2014-2015 ForgeRock AS.
+ * Portions Copyright 2026 3A Systems, LLC.
*/
package org.opends.server.backends.pluggable.spi;
@@ -56,8 +57,10 @@
void open(AccessMode accessMode) throws Exception;
/**
- * Executes a read operation. In case of a read operation rollback, implementations must ensure
- * the read operation is retried until it succeeds.
+ * Executes a read operation. In case of a read operation rollback, implementations must propagate the failure
+ * to the caller rather than replay the operation: unlike {@link WriteOperation}, a {@link ReadOperation} is not
+ * required to be idempotent, and several of them are not - they write to a stream, print, or accumulate state
+ * that a second attempt would double.
*
* @param <T>
* type of the value returned
--
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