Re: possible memory leak with SRFs
Nikhil Sontakke <nikhil.sontakke@enterprisedb.com>
From: Nikhil Sontakke <nikhil.sontakke@enterprisedb.com>
To: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2010-05-06T12:13:45Z
Lists: pgsql-hackers
Attachments
- PG_srf_memleak_v2.0.patch (text/x-patch) patch v2
> Patch attached with this mail. > The previous patch was WIP. Please take a look at this one instead. I hope this handles the cases where results are not just base datums but palloc'ed datums like string types too. Regards, Nikhils > The SRF has its own long-lived "SRF multi-call context" anyways. And > AIUI, SRFs return tuples one-by-one or do we materialize the same into > a tuplestore in some cases? > > Regards, > Nikhils > > On Wed, May 5, 2010 at 7:23 PM, Nikhil Sontakke > <nikhil.sontakke@enterprisedb.com> wrote: >> Hi, >> >> I saw this behavior with latest GIT head: >> >> create table xlarge(val numeric(19,0)); >> insert into xlarge values(generate_series(1,5)); >> >> The above generate series will return an int8 which will then be >> casted to numeric (via int8_to_numericvar) before being inserted into >> the table. I observed that the ExprContext memory associated with >> econtext->ecxt_per_tuple_memory is slowly bloating up till the end of >> the insert operation. >> >> This becomes significant the moment we try to insert a significant >> number of entries using this SRF. I can see the memory being consumed >> by the PG backend slowly grow to a large percentage. >> >> I see that the executor (take ExecResult as an example) does not reset >> the expression context early if an SRF is churning out tuples. What >> could be a good way to fix this? >> >> Regards, >> Nikhils >> -- >> http://www.enterprisedb.com >> > > > > -- > http://www.enterprisedb.com > -- http://www.enterprisedb.com