Dne 06.02.2013 16:53, Alvaro Herrera napsal:
Tom Lane escribió:
Pavel Stehule <pavel.steh...@gmail.com> writes:
>> Nice. Another interesting numbers would be device utilization,
average
>> I/O speed and required space (which should be ~2x the pgstat.stat
size
>> without the patch).
> this point is important - with large warehouse with lot of
databases
> and tables you have move stat file to some ramdisc - without it
you
> lost lot of IO capacity - and it is very important if you need
only
> half sized ramdisc
[ blink... ] I confess I'd not been paying close attention to this
thread, but if that's true I'd say the patch is DOA. Why should we
accept 2x bloat in the already-far-too-large stats file? I thought
the idea was just to split up the existing data into multiple files.
I think they are saying just the opposite: maximum disk space
utilization is now half of the unpatched code. This is because when
we
need to write the temporary file to rename on top of the other one,
the
temporary file is not of the size of the complete pgstat data
collation,
but just that for the requested database.
Exactly. And I suspect the current (unpatched) code ofter requires more
than
twice the space because of open file descriptors to already deleted
files.
Tomas
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