From: | Jeff Frost <jeff(at)pgexperts(dot)com> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-bugs(at)postgresql(dot)org |
Subject: | Re: 9.1.3 backends getting stuck in 'startup' |
Date: | 2012-05-24 22:25:37 |
Message-ID: | 7A939C5B-ABA4-4CF4-9473-F48989399813@pgexperts.com |
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Thread: | |
Lists: | pgsql-bugs |
On May 24, 2012, at 3:13 PM, Tom Lane wrote:
> Jeff Frost <jeff(at)pgexperts(dot)com> writes:
>> On 05/24/12 12:21, Tom Lane wrote:
>
> Huh. A bit bigger, but not by that much. It doesn't seem like this
> would be enough to make seqscan performance fall off a cliff, as it
> apparently did. Unless maybe the slightly-bloated catalogs were just a
> bit too large to fit in RAM, and so the repeated seqscans went from
> finding all their data in kernel disk buffers to finding none of it?
Seems unlikely.
>
>> So, interestingly, they're both quite large, but the old broken system is
>> quite a bit larger. Any other data points be helpful?
>
> I think it would be interesting to get the pg_relation_size for pg_class
> plus pg_attribute plus pg_index (which I think is everything that gets
> seqscannedd in this way) on both systems, and see how those numbers
> match up to total RAM on the box.
Server has 128GB of RAM.
Currently running system:
select pg_size_pretty(pg_relation_size('pg_class'));
pg_size_pretty
----------------
181 MB
(1 row)
select pg_size_pretty(pg_relation_size('pg_index'));
pg_size_pretty
----------------
23 MB
(1 row)
Old broken system:
select pg_size_pretty(pg_relation_size('pg_class'));
pg_size_pretty
----------------
221 MB
(1 row)
select pg_size_pretty(pg_relation_size('pg_index'));
pg_size_pretty
----------------
44 MB
(1 row)
BTW, when I connected to it this time, I had a really long time before my psql was able to send a query, so it seems to be still broken at least.
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