Re: [HACKERS] More stats about skipped vacuums

On Mon, Nov 27, 2017 at 1:49 AM, Kyotaro HORIGUCHI
<horiguchi.kyotaro@lab.ntt.co.jp> wrote:
> Hmmm. Okay, we must make stats collector more effeicient if we
> want to have additional counters with smaller significance in the
> table stats. Currently sizeof(PgStat_StatTabEntry) is 168
> bytes. The whole of the patchset increases it to 232 bytes. Thus
> the size of a stat file for a database with 10000 tables
> increases from about 1.7MB to 2.4MB.  DSM and shared dynahash is
> not dynamically expandable so placing stats on shared hash
> doesn't seem effective. Stats as a regular table could work but
> it seems too-much.

dshash, which is already committed, is both DSM-based and dynamically
expandable.

> Is it acceptable that adding a new section containing this new
> counters, which is just loaded as a byte sequence and parsing
> (and filling the corresponding hash) is postponed until a counter
> in the section is really requested?  The new counters need to be
> shown in a separate stats view (maybe named pg_stat_vacuum).

Still makes the stats file bigger.

-- 
Robert Haas
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