The most recent Stable (GA) release of MariaDB Connector/J is:
MariaDB Connector/J 2.3.0

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Release date: 16 Nov 2015

MariaDB Connector/J 1.3.0 is a Stable (GA) release.

For a description of the MariaDB Connector/J see the About the MariaDB Connector/J page.

For a list of all changes made in this release, with links to detailed information on each push, see the changelog.

Notable changes and additions

This release includes the following major enhancements :

  • Prepared statement on server side.
  • Improving memory footprint
  • New Date/Time/Timestamps implementation
  • New failover options

Prepared statements on server side

A prepared statement is a feature used to execute the same (or similar) SQL statements repeatedly with high efficiency.

This functionality is now executed on the server side.

For example:

PreparedStatement pst = connection.prepareStatement("INSERT INTO exemple VALUES (?)");
int i=1000;
while(i>0) {
    pst.setInt(1, i--);
    pst.addBatch();
}           
pst.executeBatch();

When executing connection.prepareStatement the query will be sent to the server. The server will return a statement ID.

When executing executeBatch, only this statement ID will be sent with the query parameter.

This improves performance when many queries are to be executed.

The following new parameters have been added :

cachePrepStmtsEnable/disable prepared statement cache
default is true
prepStmtCacheSizeSets the number of prepared statements that the driver will cache per VM if cachePrepStmts is enabled.
default is 250
prepStmtCacheSqlLimitMaximum length of a prepared SQL statement that the driver will cache if cachePrepStmts is enabled.
default is 2048

The prepared statement will be cached according to the above parameters.

Memory improvement

The memory footprint has been improved for query text and especially for prepared statements.

New Date/Time/Timestamps implementation

A new parameter is added :

useLegacyDatetimeCodeif false (recommended if database is new), use serverTime zone when storing Datetime/Timestamps
default is true

There is no change when the parameter useLegacyDatetimeCode is not specified or is true (it is true by default). When this parameter is set to false in the JDBC connection string, the new implementation is used. Therefore, the time zone of the server will be used, taking into account the time changes.

Example with a particular timezone:

UTC TIMEPARIS TIMECANADA TIME
2015- 2- 29T00:45:00+00002015- 2- 29T01:45:00+10002015- 2- 28 21:45:00-3000
2015- 2- 29T01:15:00+00002015- 2- 29T03:15:00+20002015- 2- 28 22:15:00-3000

If Connector/Java is using the "Europe/Paris" timezone, server "Canada/Atlantic" (UTC recommended, but not mandatory).

TimeZone.setDefault(TimeZone.getTimeZone("Europe/Paris"));
connection.createStatement().execute("CREATE TABLE daylight (t1 TIMESTAMP(6), t2 DATETIME(6))");
PreparedStatement pst = connection.prepareStatement("INSERT INTO daylight VALUES (?, ?)");
pst.setTimestamp(1, Timestamp.valueOf("2015-03-29 01:45:00"));
pst.setTimestamp(2, Timestamp.valueOf("2015-03-29 03:15:00"));
...

Using useLegacyDatetimeCode=false or not will return the same result :

ResultSet res = connection.createStatement().executeQuery("SELECT * FROM daylight");
res.next();
assertEquals(res.getTimestamp(1),Timestamp.valueOf("2015-03-29 01:45:00"));
assertEquals(res.getTimestamp(2),Timestamp.valueOf("2015-03-29 01:45:00"));
res.next();
assertEquals(res.getTimestamp(1),Timestamp.valueOf("2015-03-29 03:15:00"));
assertEquals(res.getTimestamp(2),Timestamp.valueOf("2015-03-29 03:15:00"));

The difference will be on the saved data :

with useLegacyDatetimeCode=false:

t1t2
2015-03-28 21:45:00.0000002015-03-28 22:15:00.000000

with useLegacyDatetimeCode=true:

t1t2
2015-03-29 01:45:00.0000002015-03-29 03:15:00.000000

New failover options

AssureReadOnly parameter

A new parameter is added :

assureReadOnlyIf true, in high availability, and switching to a read-only host, assure that this host is in read-only mode by setting session read-only.
default to false

When switching host to a slave (by using "connection.setReadOnly(true);" for example), if the database permit it, the connector was always setting the connection in read-only mode, so an Exception will be thrown if a data modification is done on a slave.

To improve performance, this operation will not be performed if the parameter is a assureReadOnly false (default). It's up to you to configure the slaves servers in read_only mode.

Sequential failover parameter

A new type of failover implementation as been added : Sequential.

This permits failover WITHOUT loadbalancing.

the host will be connected in the order in which they were declared.

Example when using the jdbc url string "jdbc:mysql:replication:host1,host2,host3/test". When connecting, the driver will always try first host1, and if not available host2 and following. After a host fail, the driver will reconnect according to this order.

Example :

Connecting order:

  • trying to connect to host1. Host1 is up, the driver will use this host.
  • host1 fail. The driver will connect to Host2.
  • host2 fail. If the host1 is not blacklisted anymore (timeout configure with the loadBalanceBlacklistTimeout parameter) the driver will try to connect to host1, and after host3. If host1 was blacklisted, driver would connect to host3 directly.

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