which column does your indice cover? Em Qua, 2007-08-15 às 16:36 -0300, Sebastián Baioni escreveu: > Hello, > Whe are running PostgreSQL 8.2.0 on amd64-portbld-freebsd6.2, compiled > by GCC cc (GCC) 3.4.6 [FreeBSD] 20060305. > The query only uses the index if we have a "limit n": > > Without "Limit n" > explain > select esapcuit, esapcuil > from esact00 t1 > order by esapcuit, esapcuil > > Sort (cost=843833.82..853396.76 rows=3825177 width=30) > Sort Key: esapcuit, esapcuil > -> Seq Scan on esact00 t1 (cost=0.00..111813.77 rows=3825177 > width=30) > > With "Limit n" > explain > select esapcuit, esapcuil > from esact00 t1 > order by esapcuit, esapcuil > limit 1 > > Limit (cost=0.00..1.86 rows=1 width=30) > -> Index Scan using uesact002 on esact00 t1 (cost=0.00..7129736.89 > rows=3825177 width=30) > > Our postgresql.conf is: > enable_bitmapscan = on > enable_hashagg = on > enable_hashjoin = on > enable_indexscan = on > enable_mergejoin = on > enable_nestloop = on > enable_seqscan = on > enable_sort = on > enable_tidscan = on > > Thank you. > Sebastián > > > Sebastián Baioni > http://www.acomplejados.com.ar > http://www.extremista.com.ar > http://www.coolartists.com.ar > > > ______________________________________________________________________ > > ¡Sé un mejor ambientalista! > Encontrá consejos para cuidar el lugar donde vivimos.. ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
