How Does `rewriteBatchedStatements=true` Optimize JDBC Batch Processing?

Optimizing JDBC Batch Processing with rewriteBatchedStatements=true

The JDBC parameter rewriteBatchedStatements=true significantly enhances efficiency in batch data processing by consolidating multiple SQL statements into a single network transmission, thereby reducing network latency.

Enabling this parameter instructs the JDBC driver to bundle numerous queries into a single packet rather than sending each individually. Consider the following example, where individual rows are inserted into the 'jdbc' table using separate INSERT statements:

try (Connection con = ...; PreparedStatement ps = con.prepareStatement("INSERT INTO jdbc (`name`) VALUES (?)")) {
    for (int i = 1; i < 1000; i++) {
        ps.setString(1, "Line " + i + ": ...");
        ps.addBatch();
    }
    ps.executeBatch();
}

With rewriteBatchedStatements=true activated, the JDBC driver transmits a single packet containing a combined INSERT statement like this:

INSERT INTO jdbc (`name`) VALUES ('Line 1: ...'), ('Line 2: ...'), ... ,('Line 999: ...')

Crucially, the MySQL Connector/J driver (and other compliant drivers) respects the server's max_allowed_packet setting. It checks this limit upon connection and dynamically adjusts the batch size to prevent exceeding the maximum packet size. If a single multi-row INSERT would be too large, the driver automatically fragments it into smaller, compliant packets.

By leveraging rewriteBatchedStatements=true and configuring an appropriate max_allowed_packet value, developers can substantially improve database interaction performance for batch operations, minimizing network overhead and maximizing throughput.

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