Hi all
I've recently installed pg 8.2.5 on a new server and transferred my data from 8.2.4 running on a slow old thing, via pg_dump.
One of these tables has point UK address data, with 27 million rows, and another the UK roads data, approx 4 million rows.
My problem is I have several text fields in the address data, for which postgres ignores the indexes (btree).
Using my pc_ (postcode) column:
Here's the OLD query plan on the old server.
"Index Scan using ap_idx_pc on ap (cost=
0.00..15.30 rows=1 width=188)"
" Index Cond: (((pc_)::text >= 'OX2 0'::character varying) AND ((pc_)::text < 'OX2 1'::character varying))"
" Filter: ((pc_)::text ~~ 'OX2 0%'::text)"
And the NEW:-
"Seq Scan on ap (cost=0.00..4652339.33 rows=1 width=189)"
" Filter: ((pc_)::text ~~ 'OX2 0%'::text)"
I have tried :
reindexing.
dropping the index and recreating it.
set enable_seqscan = off;
set seq_page_cost = 1000;
vacuum analyze;
vacuum full;
none of these things have worked.
the strange thing is my btree indexes on the uk roads data work fine.
There are quite a few nulls in the table, but very few in the pc column I've been using as an example.
Any help would be greatly appreciated.
Cheers
Will
