On Tue, 16 Oct 2001, CoL wrote: > --------------------------- > The 2 table query, where prog_data has ~8800 rowsn and index on prog_id: > bash-2.04$ time echo "explain select distinct > prog_id,prog_ftype,prog_fcasthour,prog_date from prog_dgy_xy,prog_data > where pxygy_pid=prog_id " | psql -Uuser db > NOTICE: QUERY PLAN: > > Unique (cost=7432549.69..7680455.07 rows=2479054 width=32) > -> Sort (cost=7432549.69..7432549.69 rows=24790538 width=32) > -> Merge Join (cost=148864.65..161189.33 rows=24790538 width=32) > -> Index Scan using prog_data_pkey on prog_data > (cost=0.00..701.12 rows=8872 width=28) > -> Sort (cost=148864.65..148864.65 rows=921013 width=4) > -> Seq Scan on prog_dgy_xy (cost=0.00..30145.13 > rows=921013 width=4)
I'm guessing that the approximately 25 million row estimate on the join has to be wrong as well given that prog_data.prog_id should be unique. Hmm, does the explain change if you vacuum analyze the other table (prog_data)? If not, what does explain show if you do a set enable_seqscan='off'; before it? ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org
