Re: SLRU statistics

On 2020/05/01 3:19, Tomas Vondra wrote:
> On Fri, May 01, 2020 at 03:02:59AM +0900, Fujii Masao wrote:
>>
>>
>> On 2020/04/02 9:41, Tomas Vondra wrote:
>>> Hi,
>>>
>>> I've pushed this after some minor cleanup and improvements.
>>
>> +static char *slru_names[] = {"async", "clog", "commit_timestamp",
>> +                              "multixact_offset", "multixact_member",
>> +                              "oldserxid", "pg_xact", "subtrans",
>> +                              "other" /* has to be last */};
>>
>> When I tried pg_stat_slru, I found that it returns a row for "pg_xact".
>> But since there is no "pg_xact" slru ("clog" slru exists instead),
>> "pg_xact" should be removed? Patch attached.
>>
>
> Yeah, I think I got confused and accidentally added both "clog" and
> "pg_xact". I'll get "pg_xact" removed.

Thanks!

Another thing I found is; pgstat_send_slru() should be called also by
other processes than backend? For example, since clog data is flushed
basically by checkpointer, checkpointer seems to need to send slru stats.
Otherwise, pg_stat_slru.flushes would not be updated.

Regards,

--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION