psql (PostgreSQL) 7.3.2I do a modification of 'access/index/indexam.c' where I comment:
#ifdef NOT_USED if (scan->keys_are_unique && scan->got_tuple) { if (ScanDirectionIsForward(direction)) { if (scan->unique_tuple_pos <= 0) scan->unique_tuple_pos++; } else if (ScanDirectionIsBackward(direction)) { if (scan->unique_tuple_pos >= 0) scan->unique_tuple_pos--; } if (scan->unique_tuple_pos == 0) return heapTuple; else return NULL; } #endif
I do not remember the references of the bug. But the solution was planned for 7.4.
I do:
I have an index on next_index_time field on table url.psql=# \di [skip] public | url_next_index_time | index | postgresql | url [skip] (11 rows)
Silly SeqScan of all the table.psql=# explain select min(next_index_time) from url \g QUERY PLAN ------------------------------------------------------------------- Aggregate (cost=85157.70..85157.70 rows=1 width=4) -> Seq Scan on url (cost=0.00..80975.56 rows=1672856 width=4) (2 rows)
psql=# explain SELECT next_index_time FROM url ORDER BY next_index_time LIMIT 1 \g
QUERY PLAN
----------------------------------------------------------------------- -------------------------
Limit (cost=0.00..0.20 rows=1 width=4)
-> Index Scan using url_next_index_time on url (cost=0.00..340431.47 rows=1672856 width=4)
(2 rows)
I ask for the same thing. That's better !
Why the planner does that ?
Jean-Gérard Pailloncy Paris, France
---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly