Re: BUG #5946: Long exclusive lock taken by vacuum (not full)

Robert Haas <robertmhaas@gmail.com>

From: Robert Haas <robertmhaas@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Greg Stark <gsstark@mit.edu>, Alvaro Herrera <alvherre@commandprompt.com>, Christopher Browne <cbbrowne@gmail.com>, Maxim Boguk <maxim.boguk@gmail.com>, pgsql-bugs <pgsql-bugs@postgresql.org>
Date: 2011-03-28T18:20:55Z
Lists: pgsql-bugs
On Mon, Mar 28, 2011 at 12:29 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> 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.

Yeah.

>> ... 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.

Well, I guess we can always try it and see.

-- 
Robert Haas
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