From: | Tomas Vondra <tv(at)fuzzy(dot)cz> |
---|---|
To: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: keeping a timestamp of the last stats reset (for a db, table and function) |
Date: | 2010-12-23 17:47:53 |
Message-ID: | 4D138B49.6010108@fuzzy.cz |
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Lists: | pgsql-hackers |
Dne 20.12.2010 00:03, Tom Lane napsal(a):
> I wrote:
>> That is not the number of interest. The number of interest is that it's
>> 8 bytes added onto a struct that currently contains 11 of 'em; in other
>> words a 9% increase in the size of the stats file, and consequently
>> about a 9% increase in the cost of updating it.
>
> Wups, sorry, I was looking at the wrong struct. It's actually an
> addition of 1 doubleword to a struct of 21 of 'em, or about 5%.
> That's still an awful lot in comparison to the prospective usefulness
> of the information.
>
> regards, tom lane
>
OK, so here goes the simplified patch - it tracks one reset timestamp
for a background writer and for each database.
regards
Tomas
PS: I've noticed Magnus posted a patch to track recovery conflicts,
adding a new view pg_stat_database_conflicts. I have not checked it yet
but it should not influence this patch.
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