Re: Function performance drops during execution of loop

Just for the record, I've increased the data volume X10 and observed only
quite small performance drop: average time per inner function call
increased from 12.6 ms to 13.3 ms.

Regards
Seref

On Wed, May 21, 2014 at 5:19 PM, Seref Arikan <
serefarikan(at)kurumsalteknoloji(dot)com> wrote:

> Thanks a lot for the hint Tom! I've replaced deletes with TRUNCATE and it
> gave a performance of 50.950 sec which is twice as fast as the drop temp
> table method, with the added benefit of not having to raise the
> max_locks_per_transaction.
>
> I also think I can't see the performance decrease pattern anymore, or the
> operation is completing before that happens, will generate more data and
> try again.
>
> Regards
> Seref
>
>
>
> On Wed, May 21, 2014 at 4:52 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
>> Seref Arikan <serefarikan(at)kurumsalteknoloji(dot)com> writes:
>> > What may be building up here? I suspect deleting all rows from the temp
>> > tables is not really deleting them since this is all happening in a
>> > transaction, but it is my uneducated guess only.
>>
>> I suspect you suspect correctly. Autovacuum does not touch temp tables,
>> so it won't help you deal with deleted tuples. Given the usage pattern
>> you're describing, I think that using a TRUNCATE rather than
>> delete-all-the-rows would help ... but if you're already doing that,
>> we need more info.
>>
>> regards, tom lane
>>
>
>