D.6.1.12. Changes in MySQL Connector/J 5.1.3 (10 September 2007)

The following features are new, compared to the 5.0 series of Connector/J

  • Support for JDBC-4.0 NCHAR, NVARCHAR and NCLOB types.

  • JDBC-4.0 support for setting per-connection client information (which can be viewed in the comments section of a query using SHOW PROCESSLIST on a MySQL server, or can be extended to support custom persistence of the information using a public interface).

  • Support for JDBC-4.0 XML processing using JAXP interfaces to DOM, SAX and StAX.

  • JDBC-4.0 standardized unwrapping to interfaces that include vendor extensions.

Functionality added or changed:

  • Connector/J now connects using an initial character set of utf-8 solely for the purpose of authentication to permit user names or database names in any character set to be used in the JDBC connection URL. (Bug#29853)

  • Added two configuration parameters:

    • blobsAreStrings: Should the driver always treat BLOBs as Strings. Added specifically to work around dubious metadata returned by the server for GROUP BY clauses. Defaults to false.

    • functionsNeverReturnBlobs: Should the driver always treat data from functions returning BLOBs as Strings. Added specifically to work around dubious metadata returned by the server for GROUP BY clauses. Defaults to false.

  • Setting rewriteBatchedStatements to true now causes CallableStatements with batched arguments to be re-written in the form "CALL (...); CALL (...); ..." to send the batch in as few client/server round trips as possible.

  • The driver now picks appropriate internal row representation (whole row in one buffer, or individual byte[]s for each column value) depending on heuristics, including whether or not the row has BLOB or TEXT types and the overall row-size. The threshold for row size that will cause the driver to use a buffer rather than individual byte[]s is configured by the configuration property largeRowSizeThreshold, which has a default value of 2KB.

  • The data (and how it is stored) for ResultSet rows are now behind an interface which enables us (in some cases) to allocate less memory per row, in that for "streaming" result sets, we re-use the packet used to read rows, since only one row at a time is ever active.

  • Added experimental support for statement "interceptors" through the com.mysql.jdbc.StatementInterceptor interface, examples are in com/mysql/jdbc/interceptors. Implement this interface to be placed "in between" query execution, so that it can be influenced (currently experimental).

  • The driver will automatically adjust the server session variable net_write_timeout when it determines its been asked for a "streaming" result, and resets it to the previous value when the result set has been consumed. (The configuration property is named netTimeoutForStreamingResults, with a unit of seconds, the value '0' means the driver will not try and adjust this value).

  • JDBC-4.0 ease-of-development features including auto-registration with the DriverManager through the service provider mechanism, standardized Connection validity checks and categorized SQLExceptions based on recoverability/retry-ability and class of the underlying error.

  • Statement.setQueryTimeout()s now affect the entire batch for batched statements, rather than the individual statements that make up the batch.

  • Errors encountered during Statement/PreparedStatement/CallableStatement.executeBatch() when rewriteBatchStatements has been set to true now return BatchUpdateExceptions according to the setting of continueBatchOnError.

    If continueBatchOnError is set to true, the update counts for the "chunk" that were sent as one unit will all be set to EXECUTE_FAILED, but the driver will attempt to process the remainder of the batch. You can determine which "chunk" failed by looking at the update counts returned in the BatchUpdateException.

    If continueBatchOnError is set to "false", the update counts returned will contain all updates up-to and including the failed "chunk", with all counts for the failed "chunk" set to EXECUTE_FAILED.

    Since MySQL doesn't return multiple error codes for multiple-statements, or for multi-value INSERT/REPLACE, it is the application's responsibility to handle determining which item(s) in the "chunk" actually failed.

  • New methods on com.mysql.jdbc.Statement: setLocalInfileInputStream() and getLocalInfileInputStream():

    • setLocalInfileInputStream() sets an InputStream instance that will be used to send data to the MySQL server for a LOAD DATA LOCAL INFILE statement rather than a FileInputStream or URLInputStream that represents the path given as an argument to the statement.

      This stream will be read to completion upon execution of a LOAD DATA LOCAL INFILE statement, and will automatically be closed by the driver, so it needs to be reset before each call to execute*() that would cause the MySQL server to request data to fulfill the request for LOAD DATA LOCAL INFILE.

      If this value is set to NULL, the driver will revert to using a FileInputStream or URLInputStream as required.

    • getLocalInfileInputStream() returns the InputStream instance that will be used to send data in response to a LOAD DATA LOCAL INFILE statement.

      This method returns NULL if no such stream has been set using setLocalInfileInputStream().

  • Setting useBlobToStoreUTF8OutsideBMP to true tells the driver to treat [MEDIUM/LONG]BLOB columns as [LONG]VARCHAR columns holding text encoded in UTF-8 that has characters outside the BMP (4-byte encodings), which MySQL server can't handle natively.

    Set utf8OutsideBmpExcludedColumnNamePattern to a regex so that column names matching the given regex will still be treated as BLOBs The regex must follow the patterns used for the java.util.regexpackage. The default is to exclude no columns, and include all columns.

    Set utf8OutsideBmpIncludedColumnNamePattern to specify exclusion rules to utf8OutsideBmpExcludedColumnNamePattern". The regex must follow the patterns used for the java.util.regex package.

Bugs fixed:

  • setObject(int, Object, int, int) delegate in PreparedStatmentWrapper delegates to wrong method. (Bug#30892)

  • NPE with null column values when padCharsWithSpace is set to true. (Bug#30851)

  • Collation on VARBINARY column types would be misidentified. A fix has been added, but this fix only works for MySQL server versions 5.0.25 and newer, since earlier versions didn't consistently return correct metadata for functions, and thus results from subqueries and functions were indistinguishable from each other, leading to type-related bugs. (Bug#30664)

  • An ArithmeticException or NullPointerException would be raised when the batch had zero members and rewriteBatchedStatements=true when addBatch() was never called, or executeBatch() was called immediately after clearBatch(). (Bug#30550)

  • Closing a load-balanced connection would cause a ClassCastException. (Bug#29852)

  • Connection checker for JBoss didn't use same method parameters using reflection, causing connections to always seem "bad". (Bug#29106)

  • DatabaseMetaData.getTypeInfo() for the types DECIMAL and NUMERIC will return a precision of 254 for server versions older than 5.0.3, 64 for versions 5.0.3 to 5.0.5 and 65 for versions newer than 5.0.5. (Bug#28972)

  • CallableStatement.executeBatch() doesn't work when connection property noAccessToProcedureBodies has been set to true.

    The fix involves changing the behavior of noAccessToProcedureBodies,in that the driver will now report all paramters as IN paramters but permit callers to call registerOutParameter() on them without throwing an exception. (Bug#28689)

  • DatabaseMetaData.getColumns() doesn't contain SCOPE_* or IS_AUTOINCREMENT columns. (Bug#27915)

  • Schema objects with identifiers other than the connection character aren't retrieved correctly in ResultSetMetadata. (Bug#27867)

  • Connection.getServerCharacterEncoding() doesn't work for servers with version >= 4.1. (Bug#27182)

  • The automated SVN revisions in DBMD.getDriverVersion(). The SVN revision of the directory is now inserted into the version information during the build. (Bug#21116)

  • Specifying a "validation query" in your connection pool that starts with "/* ping */" _exactly_ will cause the driver to instead send a ping to the server and return a fake result set (much lighter weight), and when using a ReplicationConnection or a LoadBalancedConnection, will send the ping across all active connections.

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