Question

I need to do some inserts in a cursor over about 300000 rows, this is however running slowly, any ideas on how i can make it run faster? Can i speed it up by batching the commits? So for example i would perform a commit after the 1000th row

DECLARE

  CURSOR test_cursor IS 
    SELECT a from database.mytable
BEGIN

  FOR curRow IN test_cursor LOOP

    insert into tableb (testval)
    values ('something');

  commit;

  END LOOP;
END; 

Answer 1

300000 rows is not that many rows. Unless the rows are each extremely large, you should not commit in the middle of the batch.

Intermediate commits will only achieve:

• additional overhead because each commit creates additional work,
• loss of restartability in case of error (and loss of transactional integrity),
• greater chance of running into ORA-1555

If your process is really a cursor with a single insert inside the loop, you should run a single statement:

BEGIN
   INSERT INTO tableb (col1..coln) (SELECT col1..coln FROM database.mytable);
END;

If you still need extra performance, you could look into direct insert and parallel operation but It might be over-optimization with “only” 300k rows.

By far the single greatest optimization available to you is to think in term of sets instead of the traditional procedural approach that consists of batches of single row statements.