Re: Vacuum: allow usage of more than 1GB of work mem - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Vacuum: allow usage of more than 1GB of work mem
Date
Msg-id 7684.1473185509@sss.pgh.pa.us
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In response to Re: Vacuum: allow usage of more than 1GB of work mem  (Simon Riggs <simon@2ndquadrant.com>)
Responses Re: Vacuum: allow usage of more than 1GB of work mem
List pgsql-hackers
Simon Riggs <simon@2ndquadrant.com> writes:
> Is there a reason we can't use repalloc here?

(1) repalloc will probably copy the data.

(2) that answer doesn't excuse you from choosing a limit.

We could get around (1) by something like Robert's idea of segmented
allocation, but TBH I've seen nothing on this thread to make me think
it's necessary or would even result in any performance improvement
at all.  The bigger we make that array, the worse index-cleaning
is going to perform, and complicating the data structure will add
another hit on top of that.
        regards, tom lane



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