Re: track_activity_query_size max practical size?

On 7/7/23 07:58, Ron wrote:
> On 7/7/23 09:55, Adrian Klaver wrote:
>> On 7/7/23 07:51, Adrian Klaver wrote:
>>> On 7/7/23 07:42, Ron wrote:
>>>> We've got some Very Large Queries that take a long time.
>>>
>>> An EXPLAIN(ANALYZE BUFFERS) would go a long way here.
>>>
>>>> Even setting taqs to 10KB isn't adequate, so I want to significantly
>>>> bump it, but am
>>>
>>> It is before coffee here, so you will need to spell out what taqs is?
>>
>> Did I mention lack of coffee? I see  track_activity_query_size in the
>> subject. So the issue is what with the current setting?
>
> 10KB isn't enough to capture the whole query.  Are there any bad side
> effects of increasing it from 10KB to 48KB or 64KB?

So to be clear the text of the query is large and not all of it is being
being shown in pg_stat_activity.query. I have never had the need to
increase that setting so all I can do is speculate. From the docs
'Specifies the amount of memory reserved to store the text of the
currently executing command for each active session, ...'. So given a
lot of active sessions with each query being a large text value there
could be a side effect at some point. The bigger issue would seem to be
'This parameter can only be set at server start'. So you are looking at
starting/stopping the server to find the sweet spot.

>
>>
>>>
>>>> concerned about side effects of setting it to 48KB or even 64KB.
>>>>
>>>
>>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com