Re: Less than ideal error reporting in pg_stat_statements - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Less than ideal error reporting in pg_stat_statements
Date
Msg-id 30415.1443996994@sss.pgh.pa.us
Whole thread Raw
In response to Re: Less than ideal error reporting in pg_stat_statements  (Peter Geoghegan <pg@heroku.com>)
Responses Re: Less than ideal error reporting in pg_stat_statements  (Andrew Dunstan <andrew@dunslane.net>)
Re: Less than ideal error reporting in pg_stat_statements  (Peter Geoghegan <pg@heroku.com>)
List pgsql-hackers
Peter Geoghegan <pg@heroku.com> writes:
> To be clear: I wasn't sure why you though I falsely count entries with
> dropped texts within entry_dealloc().

In the existing^H^H^Hprevious code, dropped-text entries would essentially
act as length-zero summands in the average calculation, whereas I think
we agree that they ought to be ignored; otherwise they decrease the
computed mean and thereby increase the probability of (useless) GC cycles.
In the worst case where the hashtable is mostly dropped-text entries,
which would for instance be the prevailing situation shortly after a GC
failure, we'd be calculating ridiculously small mean values and that'd
prompt extra GC cycles no?
        regards, tom lane



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