Error calling pg_stat_statements_reset() as requested intermittently about collector

[dbamohsin]

So ive noticed that on stock-pg (the collector that has the issue) we had Collector: Query Statistics Reset Frequency set - so i reckon this is something that we have done historically.. ive just disabled that to see impact

[lfittl]

@dbamohsin Thanks for the report!

Just as a quick initial note, the error message you posted is directly related to the Collector: Query Statistics Reset Frequency - the collector only calls pg_stat_statements_reset when that setting is enabled. In order to make use of this setting, you typically need to have the following helper function in place on the database (this is in addition to the pganalyze user having the pg_monitor role, which unfortunately does not include reset privileges):

CREATE OR REPLACE FUNCTION pganalyze.reset_stat_statements() RETURNS SETOF void AS
$$
  /* pganalyze-collector */ SELECT * FROM public.pg_stat_statements_reset();
$$ LANGUAGE sql VOLATILE SECURITY DEFINER;

Separately, we'll take a look to see if we can confirm that the reset erroring out causes a memory leak (it could be that the error state isn't cleaned up correctly somehow) - the data you provided should be an excellent starting point to pinpoint the problem.