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Re: Better to dump tabs as tabs, or \t?

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Marko Kreen <markokr(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Better to dump tabs as tabs, or \t?
Date: 2006-05-28 03:15:17
Message-ID: 200605280315.k4S3FHJ28587@candle.pha.pa.us (view raw or flat)
Thread:
Lists: pgsql-hackers
COPY wants \r and \n to be used because it checks for line endings, but
your change is only for the SQL strings, and you are right, it is more
porable to dump as actual bytes than backslashes.

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

Tom Lane wrote:
> "Marko Kreen" <markokr(at)gmail(dot)com> writes:
> > On 5/27/06, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >> Historically pg_dump has taken pains to dump ASCII control characters
> >> as backslash constructs, for instance \t for tab.  I am thinking this
> >> is not such a great idea, and that it'd be more portable rather than
> >> less so if we got rid of that logic and just dumped tab as tab, etc.
> >> In particular, making this play nice with standard_conforming_strings
> >> seems unpleasant: we'll have to emit E'' strings which are certainly
> >> not portable, not even to older PG releases.
> 
> > Could we just give a switch to pg_dump, which toggles between
> > standard_confirming_strings and old escaped strings?
> 
> The plan is that it'll dump according to what it finds as the
> standard_conforming_strings setting on the source server.
> If you feel a need to override that setting, you can use PGOPTIONS
> or the other usual ways to set a GUC variable for a program.
> 
> However, my thought on the point at hand is to just go over to
> dumping control characters literally in either case.  This is
> backwards-compatible to all PG versions and I don't know of a
> reason to think it wouldn't work (at least as well as the backslash
> constructs anyway) for portability to other databases.
> 
> Note: this only affects strings dumped as part of SQL commands;
> COPY data isn't at issue, since we're not planning to change the
> semantics of that.  COPY has always dumped tab as \t and I don't
> intend to change it.  But pg_dump --inserts would be affected,
> also strings appearing in view definitions and such.
> 
> We have some precedent for this in that pg_dump has by default
> dumped function definitions as $$ literals for a release or two
> now, and no one's complained of whitespace getting munged in
> function definitions.
> 
> 			regards, tom lane
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 9: In versions below 8.0, the planner will ignore your desire to
>        choose an index scan if your joining column's datatypes do not
>        match
> 

-- 
  Bruce Momjian   http://candle.pha.pa.us
  EnterpriseDB    http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +

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