From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
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To: | Dean Rasheed <dean(dot)a(dot)rasheed(at)googlemail(dot)com> |
Cc: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Memory leak in deferrable index constraints |
Date: | 2010-01-31 18:26:07 |
Message-ID: | 13724.1264962367@sss.pgh.pa.us |
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Lists: | pgsql-hackers |
Dean Rasheed <dean(dot)a(dot)rasheed(at)googlemail(dot)com> writes:
> On 31 January 2010 16:03, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> It seems a bit unlikely that this would be the largest memory leak in
>> that area. Can you show a test case that demonstrates this is worth
>> worrying about?
> create table foo(a int unique deferrable initially deferred);
> insert into foo (select * from generate_series(1, 10000000));
> begin;
> update foo set a=a+1;
> set constraints all immediate;
> commit;
Thanks. I had forgotten all the work we put into minimizing the size of
the deferred trigger queue. In this example it's only 16 bytes per
entry, whereas a 1-element List is going to involve 16 bytes for the
header, 8 bytes for the cell, plus two palloc item overheads --- and
double all that on a 64-bit machine. So yeah, this is a significant
leak. Patch applied.
regards, tom lane
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