Fix for Bug#91351 (Bug#28225464), MysqlConnectionPoolDataSource - autocommit status lost if global autocommit = 0.

Change-Id: I7a25b35b4040d2a075c2aba5b47f078c6a33a73e

Author: fjssilva

CHANGES

@@ -3,6 +3,8 @@
 
 Version 8.2.0
 
+  - Fix for Bug#91351 (Bug#28225464), MysqlConnectionPoolDataSource - autocommit status lost if global autocommit = 0.
+
   - WL#15197, Support WebauthN in fido authentication plugin.
 
   - Fix for Bug#107215 (Bug#34139593), ClassCastException: java.time.LocalDateTime cannot be cast to java.sql.Timestamp.

src/main/core-api/java/com/mysql/cj/CharsetSettings.java

@@ -54,13 +54,13 @@ public interface CharsetSettings {
      * </ol>
      * otherwise it will be set to utf8mb4_general_ci or utf8mb4_0900_ai_ci depending on server version.
      * <p>
-     * Since Protocol::HandshakeV10 and Protocol::HandshakeResponse41 has only one byte for the collation it's not possible to use indexes &gt; 255 during the
+     * Since Protocol::HandshakeV10 and Protocol::HandshakeResponse41 use only one byte for the collation it's not possible to use indexes &gt; 255 during the
      * handshake.
      * Also, ucs2, utf16, utf16le and utf32 character sets are impermissible here. Connector/J will try to use utf8mb4 instead.
      * </p>
      *
      * @param reset
-     *            reset the charsets configuration; needed for changeUser call.
+     *            reset the charsets configuration; needed for changeUser and resetServerState call.
      *
      * @return MySQL collation index to be used during the handshake.
      */

src/main/core-impl/java/com/mysql/cj/NativeCharsetSettings.java

@@ -218,10 +218,11 @@ public int configurePreHandshake(boolean reset) {
                     && (encoding = this.characterEncoding.getValue()) == null) {
                 // If none of "passwordCharacterEncoding", "connectionCollation" or "characterEncoding" is specified then use UTF-8.
                 // It would be better to use the server default collation here, to avoid unnecessary SET NAMES queries after the handshake if server
-                // default charset if not utf8, but we can not do it until server Bug#32729185 is fixed. Server cuts collation index to lower byte and, for example,
-                // if the server is started with character-set-server=utf8mb4 and collation-server=utf8mb4_is_0900_ai_ci (collation index 257) the Protocol::HandshakeV10
-                // will contain character_set=1, "big5_chinese_ci". This is true not only for MySQL 8.0, where built-in collations with indexes > 255 were first introduced,
-                // but also other server series would be affected when configured with custom collations, for which the reserved collation id range is >= 1024.
+                // default charset if not utf8, but we can not do it until server Bug#32729185 is fixed. Server cuts collation index to lower byte and, for
+                // example, if the server is started with character-set-server=utf8mb4 and collation-server=utf8mb4_is_0900_ai_ci (collation index 257) the
+                // Protocol::HandshakeV10 will contain character_set=1, "big5_chinese_ci". This is true not only for MySQL 8.0, where built-in collations with
+                // indexes > 255 were first introduced, but also other server series would be affected when configured with custom collations, for which the
+                // reserved collation id range is >= 1024.
                 this.sessionCollationIndex = MYSQL_COLLATION_INDEX_utf8mb4_0900_ai_ci;
             }
         }

src/main/core-impl/java/com/mysql/cj/NativeSession.java

@@ -827,4 +827,10 @@ public synchronized Timer getCancelTimer() {
         return this.cancelTimer;
     }
 
+    public void resetSessionState() {
+        checkClosed();
+        NativePacketPayload message = this.commandBuilder.buildComResetConnection(((NativeProtocol) this.protocol).getSharedSendPacket());
+        this.protocol.sendCommand(message, false, 0);
+    }
+
 }

src/main/protocol-impl/java/com/mysql/cj/protocol/a/NativeMessageBuilder.java

@@ -360,4 +360,10 @@ public NativePacketPayload buildComStmtExecute(NativePacketPayload sharedPacket,
         return packet;
     }
 
+    public NativePacketPayload buildComResetConnection(NativePacketPayload sharedPacket) {
+        NativePacketPayload packet = sharedPacket != null ? sharedPacket : new NativePacketPayload(1);
+        packet.writeInteger(IntegerDataType.INT1, NativeConstants.COM_RESET_CONNECTION);
+        return packet;
+    }
+
 }

src/main/user-impl/java/com/mysql/cj/jdbc/ConnectionImpl.java

@@ -545,9 +545,8 @@ public void changeUser(String userName, String newPassword) throws SQLException
             this.password = newPassword;
 
             this.session.getServerSession().getCharsetSettings().configurePostHandshake(true);
-
             this.session.setSessionVariables();
-
+            handleAutoCommitDefaults();
             setupServerForTruncationChecks();
         }
     }
@@ -1749,7 +1748,12 @@ public void releaseSavepoint(Savepoint arg0) throws SQLException {
     @Override
     public void resetServerState() throws SQLException {
         if (!this.propertySet.getBooleanProperty(PropertyKey.paranoid).getValue() && this.session != null) {
-            changeUser(this.user, this.password);
+            this.session.getServerSession().getCharsetSettings().configurePreHandshake(true);
+            this.session.resetSessionState();
+            this.session.getServerSession().getCharsetSettings().configurePostHandshake(true);
+            this.session.setSessionVariables();
+            handleAutoCommitDefaults();
+            setupServerForTruncationChecks();
         }
     }
 

src/test/java/testsuite/regression/DataSourceRegressionTest.java

@@ -577,7 +577,7 @@ public void testBug72632() throws Exception {
      * @throws Exception
      */
     @Test
-    void testBug104954() throws Exception {
+    public void testBug104954() throws Exception {
         createDatabase("testBug104954");
         createDatabase("`testBug104954?bug=104954`");
 
@@ -604,4 +604,42 @@ void testBug104954() throws Exception {
         }
     }
 
+    /**
+     * Tests fix for Bug#91351 (Bug#28225464), MysqlConnectionPoolDataSource - autocommit status lost if global autocommit = 0.
+     *
+     * @throws Exception
+     */
+    @Test
+    public void testBug91351() throws Exception {
+        try {
+            createTable("testBug91351", "(txt VARCHAR(100))");
+            this.stmt.executeUpdate("SET GLOBAL autocommit=0"); // Pre-condition: global autocommit=0.
+
+            final String testDbUrl = dbUrl + (dbUrl.contains("?") ? "&" : "?");
+            boolean isParanoid = false;
+            do {
+                MysqlConnectionPoolDataSource ds = new MysqlConnectionPoolDataSource();
+                ds.setUrl(testDbUrl + "paranoid=" + isParanoid);
+                Connection testConn = ds.getPooledConnection().getConnection();
+                testConn.createStatement().execute("SET SESSION wait_timeout=5"); // Otherwise test would hang when tearing down created artifacts.
+
+                PreparedStatement testPstmt = null;
+                String query = "INSERT INTO testBug91351 VALUES (?)";
+                testPstmt = testConn.prepareStatement(query);
+                testPstmt.setString(1, "MySQL Connector/J");
+                testPstmt.executeUpdate();
+
+                testConn.close();
+
+                this.rs = this.stmt.executeQuery("SELECT * FROM testBug91351");
+                assertTrue(this.rs.next());
+                assertEquals("MySQL Connector/J", this.rs.getString(1));
+
+                testConn.close();
+            } while (isParanoid = !isParanoid);
+        } finally {
+            this.stmt.executeUpdate("SET GLOBAL autocommit=1");
+        }
+    }
+
 }

src/test/java/testsuite/simple/DataSourceTest.java

@@ -158,27 +158,22 @@ public void testChangeUserAndCharsets() throws Exception {
         Connection connToMySQL = pooledConnection.getConnection();
         this.rs = connToMySQL.createStatement().executeQuery("SELECT @@character_set_results");
         assertTrue(this.rs.next());
-
         assertNull(this.rs.getString(1));
 
         this.rs = connToMySQL.createStatement().executeQuery("SHOW SESSION VARIABLES LIKE 'character_set_client'");
         assertTrue(this.rs.next());
-
-        // Because of utf8mb4
-        assertTrue(this.rs.getString(2).startsWith("utf8"));
+        assertTrue(this.rs.getString(2).startsWith("utf8")); // Because of utf8mb4.
 
         connToMySQL.close();
 
         connToMySQL = pooledConnection.getConnection();
         this.rs = connToMySQL.createStatement().executeQuery("SELECT @@character_set_results");
         assertTrue(this.rs.next());
-        assertEquals(null, this.rs.getString(1));
+        assertNull(this.rs.getString(1));
 
         this.rs = connToMySQL.createStatement().executeQuery("SHOW SESSION VARIABLES LIKE 'character_set_client'");
         assertTrue(this.rs.next());
-
-        // Because of utf8mb4
-        assertTrue(this.rs.getString(2).startsWith("utf8"));
+        assertTrue(this.rs.getString(2).startsWith("utf8")); // Because of utf8mb4.
 
         pooledConnection.getConnection().close();
     }