Re: [SQL] Questions about vacuum analyze - Mailing list pgsql-sql

From Tom Lane
Subject Re: [SQL] Questions about vacuum analyze
Date
Msg-id 16693.939741460@sss.pgh.pa.us
Whole thread Raw
In response to Re: [SQL] Questions about vacuum analyze  ("Steven M. Wheeler" <swheeler@sabre.com>)
List pgsql-sql
"Steven M. Wheeler" <swheeler@sabre.com> writes:
> I tried your suggestion for -S 32 through -S 1 running a select
> distinct against my history table.  I normally run with -S 2048 on the
> startup of the master process.  FYI: the history table uses the same
> layout as the currnt table, its just an hourly summation of the minute
> by minute data in currnt.  history has 189,724 records.
> Bottom line: The select never failed.

My current theory is that you were running out of disk space or else
running up against a 4-gig-per-temp-file limit in the sort that's done
for SELECT DISTINCT.  So -S wouldn't really affect matters, and testing
on a smaller table definitely won't prove anything one way or the other.

BTW, I believe -S 32 is the smallest value the backend will actually
accept --- it just ignores any attempt to set a smaller value.
        regards, tom lane


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