How Does JDBC Manage Batched Statements with MySQL\'s max_allowed_packet Limit?

Using RewriteBatchedStatements with MySQL and max_allowed_packet

JDBC's rewriteBatchedStatements configuration optimizes network overhead by packing multiple queries into a single packet. This raises concerns regarding the MySQL server's max_allowed_packet limit.

Reducing Network Overhead with RewriteBatchedStatements

When rewriteBatchedStatements is set to true,JDBC combines queries into a single network packet. For example:

<code class="java">ps.setString(1, "...");
ps.addBatch();
ps.setString(1, "...");
ps.addBatch();
ps.executeBatch();</code>

without rewriteBatchedStatements:

<code class="sql">INSERT INTO jdbc (`name`) VALUES ('Line 1: ...')
INSERT INTO jdbc (`name`) VALUES ('Line 2: ...')</code>

with rewriteBatchedStatements:

<code class="sql">INSERT INTO jdbc (`name`) VALUES ('Line 1: ...'),('Line 2: ...')</code>

JDBC's Awareness of max_allowed_packet

Yes, JDBC is aware of the max_allowed_packet value and adjusts the size of the combined queries accordingly.

Example

By enabling MySQL's general log, you can observe JDBC inspecting max_allowed_packet upon connection. Furthermore, if you set max_allowed_packet to a low value, JDBC will split batch queries into smaller packets if the combined size exceeds the limit.

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