Re: [HACKERS] LONG - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: [HACKERS] LONG
Date
Msg-id 199912122204.RAA09403@candle.pha.pa.us
Whole thread Raw
In response to Re: [HACKERS] LONG  (wieck@debis.com (Jan Wieck))
List pgsql-hackers
> Bruce Momjian wrote:
> 
> > I disagree.  By moving to another table, we don't have non-standard
> > tuples in the main table.  We can create normal tuples in the long*
> > table, of identical format, and access them just like normal tuples.
> > Having special long tuples in the main table that don't follow the
> > format of the other tuples it a certain mess.  The long* tables also
> > move the long data out of the main table so it is not accessed in
> > sequential scans.  Why keep them in the main table?
> 
>     More  ugly  and  complicated (especially for VACUUM) seems to
>     me, the we need an index on these  nonstandard  tuples,  that
>     doesn't  see  the  standard  ones,  while the regular indices
>     ignore the new long tuples. At least  if  we  want  to  delay
>     reading of long values until they're explicitly requested.
> 

Yes, good point.  No reason to create non-standard tuples if you can
avoid it.  And a separate table has performance advantages, especially
because the long tuples are by definition long and take up lots of
blocks.


--  Bruce Momjian                        |  http://www.op.net/~candle maillist@candle.pha.pa.us            |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania19026
 


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