Re: bg writer went away after reload

Yes. It is the "writer process". It is still called as background writer
process. It displays as "writer process" since PostgreSQL-8.0.

Venkata Balaji N

Sr. Database Administrator
Fujitsu Australia

On Tue, Mar 11, 2014 at 10:32 AM, Matthew Chambers
<mchambers(at)wetafx(dot)co(dot)nz>wrote:

>
> This is postgres 9.3.2.
>
> This is what the log shows.
>
> Mar 11 08:16:29 jupiter521 postgres[2026]: [8-1] 2014-03-11 08:16:29
> NZDTLOG: received SIGHUP, reloading configuration files
> Mar 11 08:16:29 jupiter521 postgres[2026]: [9-1] 2014-03-11 08:16:29
> NZDTLOG: parameter "bgwriter_lru_maxpages" changed to "200"
>
> Here are the processes I have running besides the connections.
>
> postgres 2028 0.0 8.3 17245532 8279356 ? Ss Mar09 2:42 postgres:
> checkpointer process
> postgres 2029 0.0 0.1 17245272 107900 ? Ss Mar09 0:08 postgres:
> writer process
> postgres 2030 0.2 0.0 17245272 34248 ? Ss Mar09 6:44 postgres:
> wal writer process
> postgres 2031 0.0 0.0 17246164 2596 ? Ss Mar09 0:09 postgres:
> autovacuum launcher process
> postgres 2032 0.0 0.0 18152 1244 ? Ss Mar09 0:06 postgres:
> archiver process last was 0000000100000202000000F8
> postgres 2033 0.0 0.0 18568 1636 ? Ss Mar09 1:47 postgres:
> stats collector process
> postgres 3914 0.4 0.0 17246520 2844 ? Ss Mar09 14:04 postgres:
> wal sender process postgres 192.168.122.54(48686) streaming 202/F996C000
>
> Is it the "writer process"? I was sure it was called the background
> writer before.
>
> -Matt
>
>
> On 11/03/14 12:03, Venkata Balaji Nagothi wrote:
>
>
> On Tue, Mar 11, 2014 at 8:30 AM, Matthew Chambers <mchambers(at)wetafx(dot)co(dot)nz
> > wrote:
>
>> Hi, just wondering if this is normal, DB is operating just fine.
>>
>> I upped bgwriter_lru_maxpages to 200 and issued a reload. Normally, I'd
>> see the bgwriter constantly churning as one of my main I/O using processes,
>> but now I have:
>>
>> postgres: wal writer process
>> postgres: checkpointer process
>>
>> The wal writer seems to have taken over. Does this make sense?
>>
>
> What WAL writer does is completely different from the way bgwriter
> functions. These two critical background processes of PostgreSQL performing
> independent I/O operations independently.One cannot take over another.
>
> which version of Postgres is this ?
>
> Do you see anything in the Postgres logs ? Do you see any message which
> indicates that reloading of the new configuration in postgresql.conf file
> was successful ?
>
> Venkata Balaji N
>
> Sr. Database Administrator
> Fujitsu Australia
>
>
>