Re: Remove xmin and cmin from frozen tuples

From: Josh Berkus <josh(at)agliodbs(dot)com>
To: Undisclosed(dot)Recipients: ;
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Remove xmin and cmin from frozen tuples
Date: 2005-09-02 20:30:58
Message-ID: 200509021330.58410.josh@agliodbs.com
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Tom, Alvaro,

> > It has to be a *new* table, not an *empty* table. If it's already
> > visible to other xacts then somebody else could insert into it in
> > parallel with you, because COPY doesn't take an exclusive lock.

There's still major gains to be had, for ETL, in being able to disable
logging on new tables/partitions. *particularly* partitions.

> Contrariwise, it doesn't really matter (I think) if there are WAL-logged
> records already in the table and COPY is adding more that aren't logged.
> (You might have to force COPY to start adding the rows on freshly added
> pages ... hmm ... all of a sudden I think we had this discussion
> already? I for sure remember the fresh-pages trick from some other
> thread.)

Yes, and that's what shot the proposal down before. But I don't think we
devoted sufficient discussion to the "new table" case.

--
--Josh

Josh Berkus
Aglio Database Solutions
San Francisco

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