Hi,
>>
>> case avg_tps pct_diff
>> 0 89 278 --
>> 1 88 745 0,6%
>> 2 88 282 1,1%
>> 3 86 660 2,9%
>>
>> This means that even in this extrem test case, the worst degradation is less
>> than 3%
>> (this overhead can be removed using pg_stat_statements.track_planning guc)
> Is the difference between 2 and 3 the extraneous pgss_store call to
> always store the query text if planner hook doesn't have access to the
> query text?
Yes it is,
but I agree it seems a big gap (1,8%) compared to the difference between 1 and 2 (0,5%).
Maybe this is just mesure "noise" ...
Regards
PAscal