Batch processing

[zhicwu]

• enable batch processing in Statement

  try (Statement s = connection.createStatement()) {
    s.addBatch("select 1; select 2"); // same as s.addBatch("select 1"); s.addBatch("select 2");
    s.addBatch("select 3");
    ...
    s.executeBatch();
  }

• arbitray sql in PreparedStatement

  try (PreparedStatement s = connection.prepareStatement("alter table my_table update value=? where key=2")) {
    s.setInt(1, 233);
    s.addBatch(); // addBatch(String) will result in SQLException according to JDBC spec
    ...
    s.executeBatch();
  }

• performance is slightly improved because generated batch insert statement will no longer be parsed again
  Note: Basic.insertOneRandomNumber(normal) dropped to ~274.899 from ~543463.393 because addBatch(String) was an empty method.

[github-actions]

Benchmark                           (client)  (statement)   Mode  Cnt       Score       Error  Units
Basic.insertOneRandomNumber  clickhouse-jdbc       normal  thrpt   20  539761.864 ± 12407.335  ops/s
Basic.selectOneRandomNumber  clickhouse-jdbc       normal  thrpt   20     874.187 ±    64.683  ops/s
Basic.selectOneRandomNumber  clickhouse-jdbc     prepared  thrpt   20     841.559 ±    70.248  ops/s

[enqueue]

Sorry that my PR was not ready, yet

[zhicwu]

Sorry that my PR was not ready, yet

Not a problem. I changed some code in order to add support for multi-statement SQL, so I figured that I'd better carry on to tackle this one too. To be honest, I spent too much time playing MHS lately, so I really need to hurry up :p

[github-actions]

Benchmark                           (client)  (statement)   Mode  Cnt       Score      Error  Units
Basic.insertOneRandomNumber  clickhouse-jdbc       normal  thrpt   20  548317.483 ± 6943.436  ops/s
Basic.selectOneRandomNumber  clickhouse-jdbc       normal  thrpt   20    1080.404 ±   70.840  ops/s
Basic.selectOneRandomNumber  clickhouse-jdbc     prepared  thrpt   20    1055.015 ±  100.579  ops/s