Re: Undocumented feature costs a lot of performance in COPY

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Gavin Sherry <swm(at)linuxworld(dot)com(dot)au>
Cc: pgsql-patches(at)postgresql(dot)org
Subject: Re: Undocumented feature costs a lot of performance in COPY
Date: 2002-02-25 03:42:10
Message-ID: 200202250342.g1P3gAS23872@candle.pha.pa.us
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Gavin, can I get documentation patches to match this patch? Thanks.

---------------------------------------------------------------------------

Gavin Sherry wrote:
> On Fri, 28 Dec 2001, Bruce Momjian wrote:
>
> > > Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > > > We could support keywords DELIMITER and DELIMITERS and only document
> > > > the first one.
> > >
> > > One could also argue that it should be WITH DELIMITER for more
> > > consistency with the other optional clauses.
> > >
> > > But let's put that in the TODO list, not try to get it done now...
> >
> > Updated TODO:
> >
> > COPY
> > ...
> > o Change syntax to WITH DELIMITER, (keep old syntax around?)
> >
>
> An attached patch implements this. The problem with implementing this is
> that the new syntax is:
>
> .... WITH DELIMITERS '<delim>' WITH NULL AS '<char>'
>
> Naturally, this leads to a shift/reduce conflict. Solution is more or less
> that used with CREATE DATABASE WITH ... WITH ... etc. The only ugly bit
> was mixing this with the old USING DELIMITERS ... syntax. I don't like the
> solution -- I get the feeling there's a better way to do it.
>
> The other option of course is to update yylex() to create a new token
> in the same way that the UNIONJOIN terminal is created. But I think this
> is a bit messy.
>
> Ideas or is this okay?
>
> Gavin

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