ORIGIN

JDBC Batch Operation using PreparedStatement

2023-02-12

JDBC Java Database Batch Operation Operation PreparedStatement 2 mins388 words

Note about how to do batch operation in database using JDBC.

Because UPDATE, DELETE, SELECT it self can deal with multiple data, so they don’t need to batch. Only INSERT need batch operation.

Statement

Connection conn = JDBCUtils.getConnection();
Statement st = conn.createStatement();
for(int i = 0; i < 20000; i ++) {
    String sql = "insert into goods(name)values('name_" + i + "')";
    st.execute(sql);
}

PreparedStatement

Connection conn = null;
PreparedStatement ps = null;
try {
    conn = JDBCUtils.getConnection();
    String sql = "insert into goods(name)value(?)";
    ps = conn.prepareStatement(sql);
    for(int i = 1; i <= 20000; i ++) {
        ps.setObject(1, "name_" + i);
        ps.execute();
    }
} catch (Exception e) {
    e.printStackTrace();
} finally {
    JDBCUtils.closeResource(conn, ps);
}

This method is still slow because it still need to IO in disk 20000 times.

Using Batch

using addBatch(), executeBatch(), clearBatch()
MySQL does not support batch by default, we need to add a parameter at the end of URL when getting the connection to database. ?rewriteBatchedStatements=true
Using a new version of MySQL

Connection conn = null;
PreparedStatement ps = null;
try {
    conn = JDBCUtils.getConnection();
    String sql = "insert into goods(name)value(?)";
    ps = conn.prepareStatement(sql);
    for(int i = 1; i <= 20000; i ++) {
        ps.setObject(1, "name_" + i);

        // collect sql
        ps.addBatch();

        if(i % 500 == 0) {
            // execute batch
            ps.executeBatch();

            // clear batch
            ps.clearBatch();
        }
    }
} catch (Exception e) {
    e.printStackTrace();
} finally {
    JDBCUtils.closeResource(conn, ps);
}

Best solution

Each time you run executeBatch(), the database will commit the data to database by default, this process also use time.

So we can let the insert do not auto commit. Using Connection.setAutoCommit() to prevent auto commit and Connection.commit() to commit change.

Connection conn = null;
PreparedStatement ps = null;
try {
    conn = JDBCUtils.getConnection();
    
    // set not to commit automatically
    conn.setAutoCommit(false);
    
    String sql = "insert into goods(name)value(?)";
    ps = conn.prepareStatement(sql);
    for(int i = 1; i <= 20000; i ++) {
        ps.setObject(1, "name_" + i);

        // collect sql
        ps.addBatch();

        if(i % 500 == 0) {
            // execute batch
            ps.executeBatch();

            // clear batch
            ps.clearBatch();
        }
    }
    
    // commit data
    conn.commit();
} catch (Exception e) {
    e.printStackTrace();
} finally {
    JDBCUtils.closeResource(conn, ps);
}