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Re: NOLOGGING option, or ?

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Luke Lonergan <llonergan(at)greenplum(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>,Alon Goldshuv <agoldshuv(at)greenplum(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: NOLOGGING option, or ?
Date: 2005-06-02 02:27:51
Message-ID: 200506020227.j522RpG22470@candle.pha.pa.us (view raw or flat)
Thread:
Lists: pgsql-hackers
Luke Lonergan wrote:
> 
> > 
> > Yep, we would _love_ those improvements.
> > 
> 
> Coming soon, probably from the guy you've never heard of :-)

LOL

> > 
> > I am confused why you are confused.  :-)
> > 
> > Uh, how do you do the escapes if you don't double the escape character
> > on input so you can distinguish a literal escape from one use to mark
> > special data like a literal delimiter or a null?
> 
> Escape processing would proceed as before, but the semantics would change to
> allow the use of different characters as the escape character, in addition
> to the special characters for delimiter and newline.  Also, escape
> processing would be "false" as the default, so that the only special
> characters by default would be the newline and delimiter characters.
> 
> Also of importance is the specification of newline and delimiter as
> arbitrary double byte or 8-bit characters.

I am still confused how you have reliable, never-break semantics without
special escaping.

How do you distinguis an escape-delimiter used to escape a delimiter in
the data from a literal escape-delimiter in the data being loaded --- it
seems impossible to do.

The idea of allowing a different escape character is interesting,
however, and certainly possible.  Right now we allow ESCAPE to be
changed only in CSV mode, but I suppose it is possible to allow it to be
changed in non-CSV mode as well.

Or are you saying there would be no escape at all.  If you make '@' the
escape, you can't just say @n is a newline because you need to make '@'
output as '@@' so you can distinguish @-n from a newline.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman(at)candle(dot)pha(dot)pa(dot)us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

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