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Re: PostgreSQL - Debian - Processes: postgres: writer process, etc.

From: Gavin Flower <GavinFlower(at)archidevsys(dot)co(dot)nz>
To: Bruce Momjian <bruce(at)momjian(dot)us>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-novice(at)postgresql(dot)org
Subject: Re: PostgreSQL - Debian - Processes: postgres: writer process, etc.
Date: 2012-02-14 22:47:58
Message-ID: 4F3AE49E.3040900@archidevsys.co.nz (view raw or flat)
Thread:
Lists: pgsql-novice
On 15/02/12 06:16, Bruce Momjian wrote:
> On Mon, Jan 30, 2012 at 11:05:10AM -0500, Tom Lane wrote:
>>>> What is weird to me is the "COMMAND" column as far as these four processes
>>>> are concerned.
>>>> In the "COMMAND "column I would expect a real command, not a description.
>>>> Can you explain?
>> We intentionally change the command string reported by ps for each
>> postmaster child process, so that you can tell the various processes
>> apart.  If we did not, every postmaster child would show the exact
>> same command string as the postmaster itself was launched with.
>> (To get an idea of how useless that is, try looking at "top" sometime
>> --- on most systems I've worked with, it ignores the changed command
>> strings, so you can't tell what's what.)
> I belive the 'c' command in modern versions of top toggles display of
> the current command string.
>
Yes, pressing 'c' when top is running gives a fuller description of the 
process command string, had done in Fedora for longer than I can 
remember.  So I would be surprised if any Linux distribution had not had 
it for several years.

you can also try
ps aux | grep postgres
at the command line prompt

$ ps aux | grep postgres
postgres  1777  0.0  0.8 2352592 66692 ?       S    11:21   0:01 
/usr/bin/postgres -D /var/lib/pgsql/data -p 5432
postgres  2979  0.0  0.0 181024   952 ?        Ss   11:21   0:00 
postgres: logger process
postgres  2989  0.0  0.1 2353620 14532 ?       Ss   11:21   0:00 
postgres: writer process
postgres  2990  0.0  0.0 2353620 1092 ?        Ss   11:21   0:00 
postgres: wal writer process
postgres  2991  0.0  0.0 2354356 2380 ?        Ss   11:21   0:00 
postgres: autovacuum launcher process
postgres  2992  0.0  0.0 183120  1160 ?        Ss   11:21   0:00 
postgres: stats collector process
gavin     5450  0.0  0.0 109248   848 pts/13   S+   11:45   0:00 grep 
--color=auto postgres
$

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Subject: Re: PostgreSQL - Debian - Processes: postgres: writer process, etc.
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