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* Massive delete of rows, how to proceed?
@ 2006-11-24 18:43 Arnau <arnaulist@andromeiberica.com>
2006-11-25 15:45 ` Massive delete of rows, how to proceed? Peter Childs <peterachilds@gmail.com>
2006-11-27 08:44 ` Re: Massive delete of rows, how to proceed? Merlin Moncure <mmoncure@gmail.com>
0 siblings, 2 replies; 4+ messages in thread
From: Arnau @ 2006-11-24 18:43 UTC (permalink / raw)
To: pgsql-performance
Hi all,
I have a table with statistics with more than 15 million rows. I'd
like to delete the oldest statistics and this can be about 7 million
rows. Which method would you recommend me to do this? I'd be also
interested in calculate some kind of statistics about these deleted
rows, like how many rows have been deleted for date. I was thinking in
creating a function, any recommendations?
Thank you very much
--
Arnau
^ permalink raw reply [nested|flat] 4+ messages in thread
* Massive delete of rows, how to proceed?
2006-11-24 18:43 Massive delete of rows, how to proceed? Arnau <arnaulist@andromeiberica.com>
@ 2006-11-25 15:45 ` Peter Childs <peterachilds@gmail.com>
1 sibling, 0 replies; 4+ messages in thread
From: Peter Childs @ 2006-11-25 15:45 UTC (permalink / raw)
To: pgsql-performance
On 24/11/06, Arnau <arnaulist@andromeiberica.com> wrote:
> Hi all,
>
> I have a table with statistics with more than 15 million rows. I'd
> like to delete the oldest statistics and this can be about 7 million
> rows. Which method would you recommend me to do this? I'd be also
> interested in calculate some kind of statistics about these deleted
> rows, like how many rows have been deleted for date. I was thinking in
> creating a function, any recommendations?
Copy and drop old table. If you delete you will have a massive problem
with a bloated table and vacuum will not help unless you expect the
table to grow to this size regulally otherwise vacuum full will take
ages.
Peter.
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Massive delete of rows, how to proceed?
2006-11-24 18:43 Massive delete of rows, how to proceed? Arnau <arnaulist@andromeiberica.com>
@ 2006-11-27 08:44 ` Merlin Moncure <mmoncure@gmail.com>
1 sibling, 0 replies; 4+ messages in thread
From: Merlin Moncure @ 2006-11-27 08:44 UTC (permalink / raw)
To: arnaulist@andromeiberica.com; +Cc: pgsql-performance
On 11/25/06, Arnau <arnaulist@andromeiberica.com> wrote:
> Hi all,
>
> I have a table with statistics with more than 15 million rows. I'd
> like to delete the oldest statistics and this can be about 7 million
> rows. Which method would you recommend me to do this? I'd be also
> interested in calculate some kind of statistics about these deleted
> rows, like how many rows have been deleted for date. I was thinking in
> creating a function, any recommendations?
a function, like an sql statement, operates in a single transaction
and you are locking quite a few records in this operation. merlin's
3rd rule: long running transactions are (usually) evil.
my gut says moving the keeper records to a swap table, dropping the
main table, and swapping the tables back might be better. However,
this kind of stuff can cause problems with logged in sessions because
of plan issues, beware.
do not write a function to delete records row by row unless you have
exhausted all other courses of action.
merlin
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Massive delete of rows, how to proceed?
@ 2006-11-26 00:35 andrew@pillette.com
0 siblings, 0 replies; 4+ messages in thread
From: andrew@pillette.com @ 2006-11-26 00:35 UTC (permalink / raw)
To: pgsql-performance
I don't believe DROP is necessary; use TRUNCATE instead. No need to re-create dependent objects.
"Peter Childs" <peterachilds@gmail.com> wrote ..
> On 24/11/06, Arnau <arnaulist@andromeiberica.com> wrote:
> > Hi all,
> >
> > I have a table with statistics with more than 15 million rows. I'd
> > like to delete the oldest statistics and this can be about 7 million
> > rows. Which method would you recommend me to do this? I'd be also
> > interested in calculate some kind of statistics about these deleted
> > rows, like how many rows have been deleted for date. I was thinking in
> > creating a function, any recommendations?
>
>
> Copy and drop old table. If you delete you will have a massive problem
> with a bloated table and vacuum will not help unless you expect the
> table to grow to this size regulally otherwise vacuum full will take
> ages.
>
> Peter.
>
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>
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^ permalink raw reply [nested|flat] 4+ messages in thread
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2006-11-24 18:43 Massive delete of rows, how to proceed? Arnau <arnaulist@andromeiberica.com>
2006-11-25 15:45 ` Peter Childs <peterachilds@gmail.com>
2006-11-27 08:44 ` Merlin Moncure <mmoncure@gmail.com>
2006-11-26 00:35 Re: Massive delete of rows, how to proceed? andrew@pillette.com
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