Re: Bug(?) with cursors using aggregate functions. - Mailing list pgsql-general

From Tom Lane
Subject Re: Bug(?) with cursors using aggregate functions.
Date
Msg-id 13647.1051588311@sss.pgh.pa.us
Whole thread Raw
In response to Bug(?) with cursors using aggregate functions.  (Benjamin Scherrey <scherrey@proteus-tech.com>)
Responses Re: Bug(?) with cursors using aggregate functions.  (Benjamin Scherrey <scherrey@proteus-tech.com>)
dump/restore to 7.4devel giving "[archiver (db)] error returned by PQputline"  ("Ron Mayer" <ron@intervideo.com>)
List pgsql-general
Benjamin Scherrey <scherrey@proteus-tech.com> writes:
> I've been developing a web-based selection browser using cursors and
> discovered a very frustrating little feature as I try to MOVE
> FORWARD/BACKWARD through my selection.

You can't run a nontrivial query plan (anything more than a seqscan or
indexscan) backwards with any reliability.  There are fixes for this in
CVS tip, but not in any released version :-(.  It should also be noted
that the fix consists of saving-aside copies of all rows emitted by the
underlying query, so if you are talking about a large result set you
might not like the performance...

            regards, tom lane


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