george young wrote:
[PostgreSQL 8.1.0 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) 4.0.1] I have a simple join on two tables that takes way too long. Can you help me understand what's wrong? There are indexes defined on the relevant columns. I just did a fresh vacuum --full --analyze on the two tables. Is there something I'm not seeing? [CPU is 950Mhz AMD, 256MB RAM, 15k rpm scsi disk] -- George YoungTable sizes: parameters has 2.1512e+07 tuples, run_opsets has 211745 tuples. explain analyze SELECT ro.run, ro.opset_num, p.step_num FROM run_opsets ro, parameters p WHERE ro.run = p.run AND ro.opset_num = p.opset_num and ro.run='team9'; QUERY PLAN -------------------------------------------------------------------------------------------------------------------------------------------- Nested Loop (cost=2.16..7957.40 rows=6707 width=22) (actual time=14.986..70197.129 rows=43050 loops=1) -> Index Scan using run_opsets_pkey on run_opsets ro (cost=0.00..128.75 rows=71 width=18) (actual time=0.386..62.959 rows=263 loops=1) Index Cond: (run = 'team9'::text) -> Bitmap Heap Scan on parameters p (cost=2.16..109.93 rows=27 width=22) (actual time=1.591..266.211 rows=164 loops=263) Recheck Cond: (('team9'::text = p.run) AND ("outer".opset_num = p.opset_num)) -> Bitmap Index Scan on parameters_idx (cost=0.00..2.16 rows=27 width=0) (actual time=1.153..1.153 rows=164 loops=263) Index Cond: (('team9'::text = p.run) AND ("outer".opset_num = p.opset_num)) Total runtime: 70237.727 ms (8 rows) Table "public.run_opsets" Column | Type | Modifiers --------------+-----------------------------+------------------------- run | text | not null opset | text | opset_ver | integer | opset_num | integer | not null status | opset_status | date_started | timestamp without time zone | date_done | timestamp without time zone | work_started | timestamp without time zone | lock_user | text | default 'NO-USER'::text lock_pid | integer | needs_review | text | Indexes: "run_opsets_pkey" PRIMARY KEY, btree (run, opset_num) CLUSTER -- Table "public.parameters" Column | Type | Modifiers -----------+---------+------------------------------- run | text | not null opset_num | integer | not null opset | text | not null opset_ver | integer | not null step_num | integer | not null step | text | not null step_ver | integer | not null name | text | not null value | text | split | boolean | not null default false wafers | text[] | not null default '{}'::text[] Indexes: "parameters_idx" btree (run, opset_num, step_num, opset, opset_ver, step, step_ver, name, split, wafers) "parameters_opset_idx" btree (opset, step, name) "parameters_step_idx" btree (step, name)
More for my own information (because nobody else has suggested it), would it make a difference if 'run' was a varchar field rather than text?
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