Re: track_activity_query_size max practical size?

On 7/7/23 10:13, Adrian Klaver wrote:
> 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.

Restarting is something I can do during a quiet point after the bulk of the 
day's work is complete, but before the nightly backups.

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

-- 
Born in Arizona, moved to Babylonia.