Hi, we are using a mono-column index on a huge table to try to make a quick 'select distinct ' on the column. This used to work fine, but... it does not anymore. We don't know what happened. Here are the facts: - request: SELECT dwhinv___rfovsnide::varchar FROM dwhinv WHERE dwhinv___rfovsnide > '201212_cloture' ORDER BY dwhinv___rfovsnide LIMIT 1 - Plan : Limit (cost=0.00..1.13 rows=1 width=12) (actual time=5798.915..5798.916 rows=1 loops=1) -> Index Scan using vsn_idx on dwhinv (cost=0.00..302591122.05 rows=267473826 width=12) (actual time=5798.912..5798.912 rows=1 loops=1) Index Cond: ((dwhinv___rfovsnide)::text > '201212_cloture'::text) Total runtime: 5799.141 ms - default_statistics_target = 200; - postgresql Version 8.4 - Index used : CREATE INDEX vsn_idx ON dwhinv USING btree (dwhinv___rfovsnide); There are 26 distinct values of the column. This query used to take some milliseconds at most. The index has been freshly recreated. What could be the problem ? Franck -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance