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Re: keeping a timestamp of the last stats reset (for a db, table and function)

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 (view raw or flat)
Thread:
Lists: pgsql-hackers
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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Subject: Re: keeping a timestamp of the last stats reset (for a db, table and function)
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Subject: Re: proposal : cross-column stats

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