Thread: Re: [HACKERS] PL/Perl list value return causes segfault
On Fri, Jul 29, 2005 at 11:24:37PM -0400, Bruce Momjian wrote: > > Would someone who knows perl update plperl.sgml and send me a patch? > > Also, is this still true in 8.1: > > In the current implementation, if you are fetching or returning > very large data sets, you should be aware that these will all go > into memory. That's no longer true. Please find enclosed a new patch :) Cheers, D -- David Fetter david@fetter.org http://fetter.org/ phone: +1 510 893 6100 mobile: +1 415 235 3778 Remember to vote!
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On Sat, Jul 30, 2005 at 09:47:58AM -0400, Andrew Dunstan wrote: > > > David Fetter wrote: > > You have rolled 2 problems into one - spi_query+spi_fetchrow does not > address the issue of returning large data sets. > > Suggest instead: [suggestion] Revised patch attached. Thanks for catching this :) Cheers, D -- David Fetter david@fetter.org http://fetter.org/ phone: +1 510 893 6100 mobile: +1 415 235 3778 Remember to vote!
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David Fetter wrote:
>*** 716,724 ****
>
> <listitem>
> <para>
>! In the current implementation, if you are fetching or returning
>! very large data sets, you should be aware that these will all go
>! into memory.
> </para>
> </listitem>
> </itemizedlist>
>--- 766,776 ----
>
> <listitem>
> <para>
>! If you are fetching or returning very large data sets using
>! <literal>spi_exec_query</literal>, you should be aware that
>! these will all go into memory. You can avoid this by using
>! <literal>spi_query</literal>/<literal>spi_fetchrow</literal> as
>! illustrated earlier.
> </para>
> </listitem>
> </itemizedlist>
>
>
>
>
You have rolled 2 problems into one - spi_query+spi_fetchrow does not
address the issue of returning large data sets.
Suggest instead:
<para>
If you are fetching very large data sets using
<literal>spi_exec_query</literal>, you should be aware that
these will all go into memory. You can avoid this by using
<literal>spi_query</literal> and <literal>spi_fetchrow</literal>
as illustrated earlier.
</para>
<para>
A similar problem occurs if a set-returning function passes
a large set of rows back to postgres via
<literal>return</literal>. You can avoid this
problem too by instead using <literal>return_next</literal> for
each row returned, as shown previously.
</para>
cheers
andrew
Patch applied. Thanks. --------------------------------------------------------------------------- David Fetter wrote: > On Sat, Jul 30, 2005 at 09:47:58AM -0400, Andrew Dunstan wrote: > > > > > > David Fetter wrote: > > > > You have rolled 2 problems into one - spi_query+spi_fetchrow does not > > address the issue of returning large data sets. > > > > Suggest instead: > > [suggestion] > > Revised patch attached. Thanks for catching this :) > > Cheers, > D > -- > David Fetter david@fetter.org http://fetter.org/ > phone: +1 510 893 6100 mobile: +1 415 235 3778 > > Remember to vote! [ Attachment, skipping... ] > > ---------------------------(end of broadcast)--------------------------- > TIP 1: if posting/reading through Usenet, please send an appropriate > subscribe-nomail command to majordomo@postgresql.org so that your > message can get through to the mailing list cleanly -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073