On Tue, Oct 16, 2012 at 11:24 AM, Sylvain CAILLET <scaillet@xxxxxxxxxxx> wrote:
Hi Craig,Here are the outputs :flows=# explain analyze delete from agg_t377_incoming_a40_dst_net_f5 where start_date < 1346487911000;QUERY PLAN-------------------------------------------------------------------------------------------------------------------------------------------Seq Scan on agg_t377_incoming_a40_dst_net_f5 (cost=0.00..34448.96 rows=657622 width=6) (actual time=3429.058..7135.901 rows=143 loops=1)Filter: (start_date < 1346487911000::bigint)Total runtime: 7136.191 ms(3 rows)flows=# \d agg_t377_incoming_a40_dst_net_f5Table "public.agg_t377_incoming_a40_dst_net_f5"Column | Type | Modifiers-------------+--------+-----------end_date | bigint |dst_network | inet |total_pkts | bigint |total_bytes | bigint |start_date | bigint |total_flows | bigint |Indexes:"agg_t377_incoming_a40_dst_net_f5_end_date" btree (end_date)"agg_t377_incoming_a40_dst_net_f5_start_date" btree (start_date)Thanks for your help,Sylvain
On 10/16/2012 03:50 PM, Sylvain CAILLET wrote:
> Hi to all,
>
> I've got a trouble with some delete statements. My db contains a little
> more than 10000 tables and runs on a dedicated server (Debian 6 - bi
> quad - 16Gb - SAS disks raid 0). Most of the tables contains between 2
> and 3 million rows and no foreign keys exist between them. Each is
> indexed (btree) on start_date / end_date fields (bigint). The Postgresql
> server has been tuned (I can give modified values if needed).
>
> I perform recurrent DELETE upon a table subset (~1900 tables) and each
> time, I delete a few lines (between 0 and 1200). Usually it takes
> between 10s and more than 2mn. It seems to me to be a huge amount of
> time ! An EXPLAIN ANALYZE on a DELETE shows me that the planner uses a
> Seq Scan instead of an Index Scan.
Can you post that (or paste to explain.depesz.com and link to it here)
along with a "\d tablename" from psql?
--
Craig Ringer
