I have grabbed one day slow query log and analyzed it by pgfouine, to my surprise, the slowest query is just a simple select statement:
select diggcontent_data_message.thing_id, diggcontent_data_message.KEY, diggcontent_data_message.value, diggcontent_data_message.kind FROM diggcontent_data_message WHERE diggcontent_data_message.thing_id = 3570882;
where thing_id is the primary key, guess how long it takes?
754.61 seconds!!
I tried explain analyze it and below is the result, which is very fast:
explain analyze select diggcontent_data_message.thing_id, diggcontent_data_message.KEY, diggcontent_data_message.value, diggcontent_data_message.kind FROM diggcontent_data_message WHERE diggcontent_data_message.thing_id = 3570882;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------
Index Scan using idx_thing_id_diggcontent_data_message on diggcontent_data_message (cost=0.00..15.34 rows=32 width=51) (actual time=0.080..0.096 rows=8 loops=1)
Index Cond: (thing_id = 3570882)
Total runtime: 0.115 ms
(3 rows)
so I wonder could this simple select is innocent and affected badly by other queries? how could I find those queries that really slow down the database?
thanks!