On 11/14/05, Steve Wampler <swampler@noao.edu> wrote: However, even that seems to have a much higher cost than I'd expect:
lab.devel.configdb=# explain delete from "tmp_table2" where id in
(select id from tmp_table2 where name='obsid' and value = 'oid080505');
NOTICE: QUERY PLAN:
Seq Scan on tmp_table2 (cost=0.00..65705177237.26 rows=769844 width=6)
SubPlan
-> Materialize (cost=42674.32..42674.32 rows=38 width=50)
-> Seq Scan on tmp_table2 (cost=0.00..42674.32 rows=38 width=50)
For one reason or the other, the planner things a sequential scan is the best solution. Try turning off seq_scan before the query and see if it changes the plan (set enable_seqscan off;).
I've seen this problem with sub queries and that usually solves it.
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