Re: PL/Perl Performance Problems

According to your original post, you do selects in step 1 and 2... Or
is this a different job and I've lost the thread (happens to me plenty
:) )

1. Selects about 20 Records from Table A (
- loops though the list and deletes in total about 50k records in Table B
2. For each record form Table A it then selects Records from Table C
- loops through these records about 50K in total
- for each runs a query 3 Tables, 10-20M records
- inserts a record in Table B .. about 50K
3. Returns some stats on the whole operation (100 records).

On Sat, Dec 19, 2009 at 12:07 AM, Alex - <aintokyo(at)hotmail(dot)com> wrote:
> On a 2nd thought... where does the cach come into play when i only do
> inserts and no selects.
> Alex
>
>> Date: Fri, 18 Dec 2009 23:45:07 -0700
>> Subject: Re: [GENERAL] PL/Perl Performance Problems
>> From: scott(dot)marlowe(at)gmail(dot)com
>> To: aintokyo(at)hotmail(dot)com
>> CC: tgl(at)sss(dot)pgh(dot)pa(dot)us; pgsql-general(at)postgresql(dot)org
>>
>> On Fri, Dec 18, 2009 at 11:37 PM, Alex - <aintokyo(at)hotmail(dot)com> wrote:
>> > Hmm...
>> > how can that be. This is happening every day, so its not a one off or
>> > happens once in the morning then in the afternoon. There is also no
>> > other
>> > task running on the system, its dedicated to postgres.
>> > Could the Autovacuum cause problems? Starting to invoke Analyze at the
>> > beginning of the day but the keep silent till the day timestamp breaks ?
>> > The think is that I have 4 servers setup in a similar way and all have
>> > exactly the same problem.
>>
>> What cron jobs are on that machine that run at night? Note that on
>> many OSes, maintenance crons are scheduled in a dir something like
>> /etc/cron.daily etc... On my laptop they all run at midnight. I'm
>> wondering if they're blowing out your cache so that you just don't
>> have the same performance the first time you hit a particular dataset
>> after they've run. Just a guess. You could try disabling them for a
>> day and see what happens.
>>
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