Re: performance on selecting a row in large tables

Hi Tom,

  You are right, this query is not the right approach for performance
testing. I thought that this will give an indication about the
performance of a select statement on that table.

  One of those slow queries are running on col02 which has a btree
index. But I use the 'in' expression to get a set of matching rows:

  select * from table where col02 in ('...',[...],'...')

  This query gets sometimes really slow, I guess it depends on the size
of the set used by 'in'.

  Would the query perform better when I cluster the index on col02 and
force to order the set for the in clause?

  Is there a way to disable the caching for testing? Once I ran the
query, the result set seems to be cached and the second run of the query
is fast. This makes a testing a little difficult ;-)

regards.
Rainer