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: | 2010-12-19 21:54:37 |
Message-ID: | 4D0E7F1D.9000007@fuzzy.cz |
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Dne 19.12.2010 20:28, Tom Lane napsal(a):
> Tomas Vondra <tv(at)fuzzy(dot)cz> writes:
>> Dne 19.12.2010 17:26, Tom Lane napsal(a):
>>> That seems like quite a bizarre definition. What I was envisioning was
>>> that we'd track only the time of the last whole-database stats reset.
>
>> Well, but that does not quite work. I need is to know whether the
>> snapshot is 'consistent' i.e. whether I can compare it to the previous
>> snapshot and get meaningful results (so that I can perform some analysis
>> on the difference).
>
> Oh, I see. Yeah, if that's what you want it for then partial resets
> have to change the timestamp too. I guess if we are careful to document
> it properly, this won't be too horrid.
>
> regards, tom lane
>
Well, maybe. I'd prefer the timestamp for each item, as that allows me
to determine which stats were not reset and analyze at least those data.
Plus I won't have time to write the other patch for at least a week, so
let's see whether there are serious objections agains the current patch.
I've never had problems with the pgstat.dat file, but I understand
others might, although this adds "just 8 bytes" to each item.
regards
Tomas
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