Hi Tom,
Le Wed, 29 Jan 2003 11:09:37 -0500
Tom Lane <tgl@sss.pgh.pa.us> a écrit:
> eurlix <eurlix@libertysurf.fr> writes:
> > I use Postgres 7.0 on a mandrake 8.0 and I am really novice
> > with Postgres and SQL.
>
> You really, really should update to something newer than 7.0.
> The list of bugs we've fixed since then would make your blood run
> cold.
Ok, if you say that, I shall to go to update (but it seem to be a big work).
Otherwise, I have fastly read again the ~940 lines of HISTORY between 7.0
and 7.2 and, unless because the season, my blood isn't too cold ^-).
In fact, I just try to use pg in replacement of ISAM files (in a first
time) for COBOL progams.
>
> > If I try :
> > select * from cpjo order by joMA, joJNL, joFOL ;
> > I obtain :
> > ERROR: cannot open segment 1 of relation cpjo
> > (target block 1346502656): No such file or directory
>
> Is that query using an index? (Try EXPLAINing the query to find
> out.) If so, I'd suggest dropping and recreating that index. 7.0 is
> far enough back that I'm not sure REINDEX works real well in it, if
> it has it at all.
I have tried "reindex table cpjo" and obtained
NOTICE: table 'cpjo' wasn't reindexed
but "reindex table cpjo force;" seem to works
and now the previous request works.
Explain give :
eurlix=> explain select * from cpjo order by joma, jojnl,jofol;
NOTICE: QUERY PLAN:
Sort (cost=174.93..174.93 rows=394 width=216)
-> Seq Scan on cpjo (cost=0.00..157.94 rows=394 width=216)
EXPLAIN
If I well understand (my english is not very good), pg make a sequential
research on the table : curious because joma+jojnl+jofol is the primary
an unique index. Perhaps because I ask all the table, but I hope it don't
make a sort after !
In all cases, it is very fast, and if I type :
eurlix=> explain select * from cpjo where joma='200206' order by joma, jojnl,jofol;
NOTICE: QUERY PLAN:
Index Scan using cpjo_pkey on cpjo (cost=0.00..5.15 rows=4 width=216)
EXPLAIN
seem this works not too bad.
Thanks and Regards,
--
Alain Lucari Eurlix
1, rue Reine Elisabeth von Witellsbach
(Reine des Belges)
13001 Marseille
FRANCE
