Re: Too slow "Analyze" for the table with data in Thai language

From: "Timur Luchkin" <timur(dot)luchkin(at)gmail(dot)com>
To: "Peter Geoghegan" <pg(at)bowt(dot)ie>
Cc: pgsql-bugs(at)postgresql(dot)org, "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Subject: Re: Too slow "Analyze" for the table with data in Thai language
Date: 2016-07-06 07:47:49
Message-ID: emb351f641-830d-4ccd-a07a-e6e49a967605@luchkin-new
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Hello,

complete result of the perf is in the attachment.
The part with glibc looks like:

# Children Self Samples Command Shared Object
Symbol
# ........ ........ ............ .............
.......................
....................................................
59.26% 59.25% 815883 postgres libc-2.23.so
[.] __strcoll_l

--59.26%--__strcoll_l

p.s.
1. perf executed during 'long' ANALYZE as "perf record -a -g";
2. test server has 2 CPU cores
3. this is dedicated server without any parallel activity

--
Timur Luchkin

>On Tue, Jul 5, 2016 at 8:33 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> So ... why do you think this is a Postgres bug and not a glibc bug?
>> We have no control over what happens inside strcoll().
>
>I'd be interested in seeing exactly where time is spent by glibc.
>Perhaps Timur can use perf to show us a profile using the default perf
>event type:
>
>https://wiki.postgresql.org/wiki/Profiling_with_perf
>
>--
>Peter Geoghegan

Attachment Content-Type Size
out.txt.bz2 application/octet-stream 12.1 KB

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