> In my experience these often not work well with pg_stat_statements today > because > of their own bloat problem, just like with temp tables. You quickly have way > too many > unique entries, and your query text file accumulates a lot of duplicative > entries > (since the same query text gets repeated in the text file, since its queryid > is different), > to the point that you can't monitor your workload at all anymore.
That is true in terms of pg_stat_statements, and I have seen users have to increase pg_stat_statements.max to something much higher to avoid the bloat and constant deallocs/GC. But, besides pg_stat_statements, queryId is used to group queries for database load monitoring ( pg_stat_activity sampling). As of now, different schemas are tracked separately, but with this change they will be merged. This may come as a surprise to use-cases that rely on the existing behavior. But I do agree that pg_s_s bloat is a big pain point, so this change should be positive overall. Let's see if there are enough complaints to force us to reconsider. -- Sami Imseih Amazon Web Services (AwS)
