Re: skip WAL on COPY patch

From: Alvaro Herrera <alvherre(at)commandprompt(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Steve Singer <ssinger(at)ca(dot)afilias(dot)info>, PostgreSQL-development Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: skip WAL on COPY patch
Date: 2011-08-23 20:51:43
Message-ID: 1314132622-sup-1708@alvh.no-ip.org
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Excerpts from Robert Haas's message of mar ago 23 17:43:13 -0300 2011:
> On Tue, Aug 23, 2011 at 4:17 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> >> What I think would be really interesting is a way to make this work
> >> when the table *isn't* empty.  In other words, have a COPY option that
> >> (1) takes an exclusive lock on the table, (2) writes the data being
> >> inserted into new pages beyond the old EOF, and (3) arranges for crash
> >> recovery or transaction abort to truncate the table back to its
> >> previous length.  Then you could do fast bulk loads even into a table
> >> that's already populated, so long as you don't mind that the table
> >> will be excusive-locked and freespace within existing heap pages won't
> >> be reused.
> >
> > What are you going to do with the table's indexes?
>
> Oh, hmm. That's awkward.

If you see what I proposed, it's simple: you can scan the new segment(s)
and index the tuples found there (maybe in bulk which would be even
faster).

--
Álvaro Herrera <alvherre(at)commandprompt(dot)com>
The PostgreSQL Company - Command Prompt, Inc.
PostgreSQL Replication, Consulting, Custom Development, 24x7 support

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