Re: how many tuples on a cursor? - Mailing list pgsql-sql

From Christoph Haller
Subject Re: how many tuples on a cursor?
Date
Msg-id 42760C37.BD6531A8@rodos.fzk.de
Whole thread Raw
In response to how many tuples on a cursor?  (Andreas Kretschmer <akretschmer@despammed.com>)
Responses Re: how many tuples on a cursor?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-sql
Andreas Kretschmer wrote:
> 
> Hello,
> 
> I want to know how many tuples there on a cursor, and i found
>
http://groups.google.de/groups?hl=de&lr=&threadm=3ACA7BB0.7020106%402cactus.com&rnum=7&prev=/groups%3Fhl%3Dde%26lr%3D%26q%3Dpostgres%2Bcursor%2Bcount%26btnG%3DSuche
> 
> But, this posting is very old (2001-04-03), i'm using 7.4.6.
> 
> Is there now a way to get the total number of rows in a CURSOR?
> 
> Andreas
> --

Assuming you are using the libpq interface, 
after FETCH ALL you'll get the number of rows 
by PQntuples(). 
What else seems to work is MOVE 2147483647 
(INT_MAX) and then get the max number of rows 
by PQcmdTuples(). 
Back to the beginning by FETCH ABSOLUTE 0. 
But I have no idea how expensive this MOVE is. 

Regards, Christoph


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