Tuesday, October 18, 2005

Key parameters for MySQL Cluster

Two parameters that you want to keep track of for MySQL Cluster is:

If this is set to 1 you get very fast SELECT COUNT(*) but most other
queries become much slower. So if your normal query scenario is
primary key lookups then set this parameter to 0. It can have a
radical effect on performance. This parameter exists in 4.1 and

This parameter is introduced in 5.0 and if set enables condition pushdown.
As an example if one does a query like:
SELECT * FROM t1 WHERE name LIKE %adam;
Then the LIKE expression can be pushed down to the data node and be evaluated
in parallel for much higher execution speed.

So both those parameters can give radical performance effect in certain query types.

1 comment:

Fortxun said...

This was a useful post, maybe you can update it to the current version.

Whats new that's as important as these two for performance tuning?.