From e417cd1a6892d2810e8baf733bb09a3ae5a3c4c2 Mon Sep 17 00:00:00 2001
From: Valery Kharseko <vharseko@3a-systems.ru>
Date: Wed, 23 Apr 2025 07:58:07 +0000
Subject: [PATCH] [#496] FIX JDBC storage update concurrency (#512)

---
 opendj-server-legacy/src/main/java/org/opends/server/backends/jdbc/Storage.java |   96 ++++++++++++++++++++++++++++++++++++-----------
 1 files changed, 73 insertions(+), 23 deletions(-)

diff --git a/opendj-server-legacy/src/main/java/org/opends/server/backends/jdbc/Storage.java b/opendj-server-legacy/src/main/java/org/opends/server/backends/jdbc/Storage.java
index 684c866..243daa1 100644
--- a/opendj-server-legacy/src/main/java/org/opends/server/backends/jdbc/Storage.java
+++ b/opendj-server-legacy/src/main/java/org/opends/server/backends/jdbc/Storage.java
@@ -34,6 +34,7 @@
 import org.opends.server.types.RestoreConfig;
 import org.opends.server.util.BackupManager;
 
+import java.nio.ByteBuffer;
 import java.security.MessageDigest;
 import java.sql.*;
 import java.util.*;
@@ -80,11 +81,11 @@
 		return statement.executeQuery();
 	}
 
-	boolean execute(PreparedStatement statement) throws SQLException {
+	int execute(PreparedStatement statement) throws SQLException {
 		if (logger.isTraceEnabled()) {
 			logger.trace(LocalizableMessage.raw("jdbc: %s",statement));
 		}
-		return statement.execute();
+		return statement.executeUpdate();
 	}
 
     Connection getConnection() throws Exception {
@@ -118,7 +119,7 @@
 				public String load(TreeName treeName) throws Exception {
 					final MessageDigest md = MessageDigest.getInstance("SHA-224");
 					final byte[] messageDigest = md.digest(treeName.toString().getBytes());
-					final StringBuilder hashtext = new StringBuilder();
+					final StringBuilder hashtext = new StringBuilder(56);
 					for (byte b : messageDigest) {
 						String hex = Integer.toHexString(0xff & b);
 						if (hex.length() == 1) hashtext.append('0');
@@ -203,14 +204,14 @@
 		return Arrays.equals(NULL,db)?new byte[0]:db;
 	}
 
-	final LoadingCache<byte[],String> key2hash= CacheBuilder.newBuilder()
-			.maximumSize(32000)
-			.build(new CacheLoader<byte[], String>() {
+	final LoadingCache<ByteBuffer,String> key2hash= CacheBuilder.newBuilder()
+			.softValues()
+			.build(new CacheLoader<ByteBuffer, String>() {
 				@Override
-				public String load(byte[] key) throws Exception {
+				public String load(ByteBuffer key) throws Exception {
 					final MessageDigest md = MessageDigest.getInstance("SHA-512");
-					final byte[] messageDigest = md.digest(key);
-					final StringBuilder hashtext = new StringBuilder();
+					final byte[] messageDigest = md.digest(key.array());
+					final StringBuilder hashtext = new StringBuilder(128);
 					for (byte b : messageDigest) {
 						String hex = Integer.toHexString(0xff & b);
 						if (hex.length() == 1) hashtext.append('0');
@@ -230,7 +231,7 @@
 		@Override
 		public ByteString read(TreeName treeName, ByteSequence key) {
 			try (final PreparedStatement statement=con.prepareStatement("select v from "+getTableName(treeName)+" where h=? and k=?")){
-				statement.setString(1,key2hash.get(key.toByteArray()));
+				statement.setString(1,key2hash.get(ByteBuffer.wrap(key.toByteArray())));
 				statement.setBytes(2,real2db(key.toByteArray()));
 				try(ResultSet rc=executeResultSet(statement)) {
 					return rc.next() ? ByteString.wrap(rc.getBytes("v")) : null;
@@ -324,14 +325,65 @@
 
 		@Override
 		public void put(TreeName treeName, ByteSequence key, ByteSequence value) {
-			delete(treeName,key);
-			try (final PreparedStatement statement=con.prepareStatement("insert into "+getTableName(treeName)+" (h,k,v) values(?,?,?) ")){
-				statement.setString(1,key2hash.get(key.toByteArray()));
-				statement.setBytes(2,real2db(key.toByteArray()));
-				statement.setBytes(3,value.toByteArray());
-				execute(statement);
-			}catch (SQLException|ExecutionException e) {
-				throw new StorageRuntimeException(e);
+			try {
+				upsert(treeName, key, value);
+			} catch (SQLException|ExecutionException e) {
+				throw new RuntimeException(e);
+			}
+		}
+
+		boolean upsert(TreeName treeName, ByteSequence key, ByteSequence value) throws SQLException, ExecutionException {
+			final String driverName=((CachedConnection) con).parent.getClass().getName();
+			if (driverName.contains("postgres")) { //postgres upsert
+				try (final PreparedStatement statement = con.prepareStatement("insert into " + getTableName(treeName) + " (h,k,v) values (?,?,?) ON CONFLICT (h, k) DO UPDATE set v=excluded.v")) {
+					statement.setString(1, key2hash.get(ByteBuffer.wrap(key.toByteArray())));
+					statement.setBytes(2, real2db(key.toByteArray()));
+					statement.setBytes(3, value.toByteArray());
+					return (execute(statement) == 1 && statement.getUpdateCount() > 0);
+				}
+			}else if (driverName.contains("mysql")) { //mysql upsert
+				try (final PreparedStatement statement = con.prepareStatement("insert into " + getTableName(treeName) + " (h,k,v) values (?,?,?) as new ON DUPLICATE KEY UPDATE v=new.v")) {
+					statement.setString(1, key2hash.get(ByteBuffer.wrap(key.toByteArray())));
+					statement.setBytes(2, real2db(key.toByteArray()));
+					statement.setBytes(3, value.toByteArray());
+					return (execute(statement) == 1 && statement.getUpdateCount() > 0);
+				}
+			}else if (driverName.contains("oracle")) { //ANSI MERGE without ;
+				try (final PreparedStatement statement = con.prepareStatement("merge into " + getTableName(treeName) + " old using (select ? h,? k,? v from dual) new on (old.h=new.h and old.k=new.k) WHEN MATCHED THEN UPDATE SET old.v=new.v WHEN NOT MATCHED THEN INSERT (h,k,v) VALUES (new.h,new.k,new.v)")) {
+					statement.setString(1, key2hash.get(ByteBuffer.wrap(key.toByteArray())));
+					statement.setBytes(2, real2db(key.toByteArray()));
+					statement.setBytes(3, value.toByteArray());
+					return (execute(statement) == 1 && statement.getUpdateCount() > 0);
+				}
+			}else if (driverName.contains("microsoft")) { //ANSI MERGE with ;
+				try (final PreparedStatement statement = con.prepareStatement("merge into " + getTableName(treeName) + " old using (select ? h,? k,? v) new on (old.h=new.h and old.k=new.k) WHEN MATCHED THEN UPDATE SET old.v=new.v WHEN NOT MATCHED THEN INSERT (h,k,v) VALUES (new.h,new.k,new.v);")) {
+					statement.setString(1, key2hash.get(ByteBuffer.wrap(key.toByteArray())));
+					statement.setBytes(2, real2db(key.toByteArray()));
+					statement.setBytes(3, value.toByteArray());
+					return (execute(statement) == 1 && statement.getUpdateCount() > 0);
+				}
+			}else { //ANSI SQL: try update before insert with not exists
+				return update(treeName,key,value) || insert(treeName,key,value);
+			}
+		}
+
+		boolean insert(TreeName treeName, ByteSequence key, ByteSequence value) throws SQLException, ExecutionException {
+			try (final PreparedStatement statement = con.prepareStatement("insert into " + getTableName(treeName) + " (h,k,v) select ?,?,? where not exists (select 1 from "+getTableName(treeName)+" where  h=? and k=? )")) {
+				statement.setString(1, key2hash.get(ByteBuffer.wrap(key.toByteArray())));
+				statement.setBytes(2, real2db(key.toByteArray()));
+				statement.setBytes(3, value.toByteArray());
+				statement.setString(4, key2hash.get(ByteBuffer.wrap(key.toByteArray())));
+				statement.setBytes(5, real2db(key.toByteArray()));
+				return (execute(statement)==1 && statement.getUpdateCount()>0);
+			}
+		}
+
+		boolean update(TreeName treeName, ByteSequence key, ByteSequence value) throws SQLException, ExecutionException {
+			try (final PreparedStatement statement=con.prepareStatement("update "+getTableName(treeName)+" set v=? where h=? and k=?")){
+				statement.setBytes(1,value.toByteArray());
+				statement.setString(2,key2hash.get(ByteBuffer.wrap(key.toByteArray())));
+				statement.setBytes(3,real2db(key.toByteArray()));
+				return (execute(statement)==1 && statement.getUpdateCount()>0);
 			}
 		}
 
@@ -345,8 +397,7 @@
 	        }
 	        if (newValue == null)
 	        {
-	        	delete(treeName, key);
-	        	return true;
+				return delete(treeName, key);
 	        }
 	        put(treeName,key,newValue);
 			return true;
@@ -355,13 +406,12 @@
 		@Override
 		public boolean delete(TreeName treeName, ByteSequence key) {
 			try (final PreparedStatement statement=con.prepareStatement("delete from "+getTableName(treeName)+" where h=? and k=?")){
-				statement.setString(1,key2hash.get(key.toByteArray()));
+				statement.setString(1,key2hash.get(ByteBuffer.wrap(key.toByteArray())));
 				statement.setBytes(2,real2db(key.toByteArray()));
-				execute(statement);
+				return (execute(statement)==1 && statement.getUpdateCount()>0);
 			}catch (SQLException|ExecutionException e) {
 				throw new StorageRuntimeException(e);
 			}
-			return true;
 		}
 	}
 	

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