Re: init_sequence spill to hash table - Mailing list pgsql-hackers

From Andres Freund
Subject Re: init_sequence spill to hash table
Date
Msg-id 20131115104434.GA31846@awork2.anarazel.de
Whole thread Raw
In response to Re: init_sequence spill to hash table  (Heikki Linnakangas <hlinnakangas@vmware.com>)
Responses Re: init_sequence spill to hash table  (Heikki Linnakangas <hlinnakangas@vmware.com>)
List pgsql-hackers
On 2013-11-15 12:31:54 +0200, Heikki Linnakangas wrote:
> On 15.11.2013 07:47, David Rowley wrote:
> >On Fri, Nov 15, 2013 at 3:03 AM, Heikki Linnakangas <hlinnakangas@vmware.com
> >>wrote
> >>
> >>I think that means that we should just completely replace the list with
> >>the hash table. The difference with a small N is lost in noise, so there's
> >>no point in keeping the list as a fast path for small N. That'll make the
> >>patch somewhat simpler.
> >
> >Attached is a much more simple patch which gets rid of the initial linked
> >list.
> 
> Thanks, committed with minor copy-editing. I dialed down the initial size of
> the hash table from 1000 to 16, that ought to be enough.

I am slightly confused by the use of HASH_CONTEXT without setting
ctl->hcxt, that works, but seems more like an accident.

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services



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