Re: BUG #5946: Long exclusive lock taken by vacuum (not full) - Mailing list pgsql-bugs

From Tom Lane
Subject Re: BUG #5946: Long exclusive lock taken by vacuum (not full)
Date
Msg-id 18898.1301286552@sss.pgh.pa.us
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In response to Re: BUG #5946: Long exclusive lock taken by vacuum (not full)  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: BUG #5946: Long exclusive lock taken by vacuum (not full)  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-bugs
Robert Haas <robertmhaas@gmail.com> writes:
> I think we've had a number of pieces of evidence that suggest that
> extending 8kB at a time is too costly, but I agree with Greg that the
> idea of extending an arbitrarily large table by 10% at a time is
> pretty frightening - that could involve allocating a gigantic amount
> of space on a big table.  I would be inclined to do something like
> extend by 10% of table or 1MB, whichever is smaller.

Sure, something like that sounds sane, though the precise numbers
need some validation.

> ... And a 1MB extension is probably also small enough
> that we can do it in the foreground without too much of a hiccup.

Less than convinced about this.

            regards, tom lane

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