Help trying to tune query that executes 40x slower than in SqlServer

From: Hugo Ferreira <bytter(at)gmail(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Help trying to tune query that executes 40x slower than in SqlServer
Date: 2005-03-07 17:01:58
Message-ID: 4e8efcf50503070901406808be@mail.gmail.com
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Hi there :-)

I'm really, really having trouble with this query... It is a part of,
hmmm... 200 similar querys that I dinyamically build and run in a
stored procedure. This one, for example, takes 27seconds to run. The
whole stored procedure executes in about 15minutes. This is too much
when compared to the exact same database, with the same indexes and
same data running under SqlServer 2000, which takes 21seconds to run
the whole batch.

Any help would be extremely appreciated. I've also tried to tune up
the configuration

insert into MRS_REPLICATION_OUT select 514, 10000168, C.contxt_id,
C.contxt_elmt_ix, CAST(null as NUMERIC(18)), CAST(null as
NUMERIC(18)), CAST(null as NUMERIC(18)), CAST(null as NUMERIC(18)),
CAST(null as NUMERIC(18)), null, 1 from c2iedm.CONTXT as P inner join
c2iedm.CONTXT_ELMT as C on (P.contxt_id=C.contxt_id) inner join
MRS_REPLICATION_OUT as S on S.ent_id=10000029 and (CAST(P.contxt_id AS
numeric(18)) = S.pk1) inner join MRS_TRANSACTION TRANS on
TRANS.trans_id=514 left join NON_REPL_DATA_OWNER NRDO on
NRDO.non_repl_data_owner_id=C.owner_id left join REPL_DATA_OWNER_RSDNC
RDOR on RDOR.owner_id=C.owner_id and
RDOR.rsdnc_node_id=TRANS.recv_node_id left join MRS_REPLICATION_OUT
OUT on OUT.trans_id=514 and OUT.ent_id=10000168 and ((CAST(C.contxt_id
AS numeric(18)) = OUT.pk1 AND CAST(C.contxt_elmt_ix AS numeric(18)) =
OUT.pk2)) inner join MRS_TRANSACTION RED_TRANS on
TRANS.prov_node_id=RED_TRANS.prov_node_id and
TRANS.recv_node_id=RED_TRANS.recv_node_id left join
MRS_REPLICATION_OUT RED_OUT on RED_TRANS.cat_code = 'OUT' and
RED_TRANS.trans_type in ('X01', 'X02') and
RED_TRANS.trans_id=RED_OUT.trans_id where S.age=0 and S.trans_id=514
and (NRDO.non_repl_data_owner_id is null) AND (RDOR.repl_data_owner_id
is null) AND (OUT.trans_id is null) AND (RED_OUT.trans_id is null);

This kind of inserts generate few rows. Between 8k and 15k for this particular
insert, and about 20k for the whole batch. If I try to run a batch
to generate about 50k rows, then I'll be stuck here for more that 45h.
Compare this to 12minutes when running SqlServer 2000.

Here is the result of explain analyze:

"Merge Left Join (cost=1338.32..1377.99 rows=45 width=32) (actual
time=719.000..26437.000 rows=14862 loops=1)"
" Merge Cond: ("outer".trans_id = "inner".trans_id)"
" Join Filter: (("outer".cat_code = 'OUT'::bpchar) AND
(("outer".trans_type = 'X01'::bpchar) OR ("outer".trans_type =
'X02'::bpchar)))"
" Filter: ("inner".trans_id IS NULL)"
" -> Sort (cost=1067.36..1067.47 rows=45 width=56) (actual
time=719.000..735.000 rows=14862 loops=1)"
" Sort Key: red_trans.trans_id"
" -> Merge Join (cost=851.66..1066.12 rows=45 width=56)
(actual time=407.000..673.000 rows=14862 loops=1)"
" Merge Cond: ("outer".recv_node_id = "inner".recv_node_id)"
" Join Filter: ("outer".prov_node_id = "inner".prov_node_id)"
" -> Nested Loop Left Join (cost=847.14..987.28
rows=3716 width=60) (actual time=407.000..610.000 rows=14862 loops=1)"
" Join Filter: ((("outer".contxt_id)::numeric(18,0)
= "inner".pk1) AND (("outer".contxt_elmt_ix)::numeric(18,0) =
"inner".pk2))"
" Filter: ("inner".trans_id IS NULL)"
" -> Merge Left Join (cost=718.22..746.87
rows=3716 width=60) (actual time=407.000..563.000 rows=14862 loops=1)"
" Merge Cond: (("outer".recv_node_id =
"inner".rsdnc_node_id) AND ("outer".owner_id = "inner".owner_id))"
" Filter: ("inner".repl_data_owner_id IS NULL)"
" -> Sort (cost=717.19..726.48 rows=3716
width=74) (actual time=407.000..423.000 rows=14862 loops=1)"
" Sort Key: trans.recv_node_id, c.owner_id"
" -> Nested Loop Left Join
(cost=1.01..496.84 rows=3716 width=74) (actual time=0.000..312.000
rows=14862 loops=1)"
" Join Filter:
("inner".non_repl_data_owner_id = "outer".owner_id)"
" Filter:
("inner".non_repl_data_owner_id IS NULL)"
" -> Nested Loop
(cost=0.00..412.22 rows=3716 width=74) (actual time=0.000..186.000
rows=14862 loops=1)"
" -> Seq Scan on
mrs_transaction trans (cost=0.00..2.05 rows=1 width=28) (actual
time=0.000..0.000 rows=1 loops=1)"
" Filter: (trans_id =
514::numeric)"
" -> Nested Loop
(cost=0.00..373.01 rows=3716 width=46) (actual time=0.000..139.000
rows=14862 loops=1)"
" Join Filter:
("outer".contxt_id = "inner".contxt_id)"
" -> Nested Loop
(cost=0.00..4.81 rows=1 width=16) (actual time=0.000..0.000 rows=4
loops=1)"
" Join Filter:
(("inner".contxt_id)::numeric(18,0) = "outer".pk1)"
" -> Index
Scan using ix_mrs_replication_out_all on mrs_replication_out s
(cost=0.00..3.76 rows=1 width=16) (actual time=0.000..0.000 rows=4
loops=1)"
" Index
Cond: ((ent_id = 10000029::numeric) AND (age = 0::numeric) AND
(trans_id = 514::numeric))"
" -> Seq Scan
on contxt p (cost=0.00..1.02 rows=2 width=16) (actual
time=0.000..0.000 rows=2 loops=4)"
" -> Seq Scan on
contxt_elmt c (cost=0.00..275.31 rows=7431 width=46) (actual
time=0.000..7.500 rows=7431 loops=4)"
" -> Materialize
(cost=1.01..1.02 rows=1 width=12) (actual time=0.000..0.001 rows=1
loops=14862)"
" -> Seq Scan on
non_repl_data_owner nrdo (cost=0.00..1.01 rows=1 width=12) (actual
time=0.000..0.000 rows=1 loops=1)"
" -> Sort (cost=1.03..1.03 rows=2 width=42)
(actual time=0.000..0.000 rows=2 loops=1)"
" Sort Key: rdor.rsdnc_node_id, rdor.owner_id"
" -> Seq Scan on repl_data_owner_rsdnc
rdor (cost=0.00..1.02 rows=2 width=42) (actual time=0.000..0.000
rows=2 loops=1)"
" -> Materialize (cost=128.92..128.93 rows=1
width=42) (actual time=0.000..0.000 rows=0 loops=14862)"
" -> Seq Scan on mrs_replication_out "out"
(cost=0.00..128.92 rows=1 width=42) (actual time=0.000..0.000 rows=0
loops=1)"
" Filter: ((trans_id = 514::numeric)
AND (ent_id = 10000168::numeric))"
" -> Sort (cost=4.52..4.73 rows=84 width=52) (actual
time=0.000..15.000 rows=1 loops=1)"
" Sort Key: red_trans.recv_node_id"
" -> Seq Scan on mrs_transaction red_trans
(cost=0.00..1.84 rows=84 width=52) (actual time=0.000..0.000 rows=1
loops=1)"
" -> Sort (cost=270.96..277.78 rows=2728 width=10) (actual
time=0.000..5255.000 rows=8932063 loops=1)"
" Sort Key: red_out.trans_id"
" -> Seq Scan on mrs_replication_out red_out
(cost=0.00..115.28 rows=2728 width=10) (actual time=0.000..0.000
rows=602 loops=1)"
"Total runtime: 27094.000 ms"

Once again, thanks in advance.

Hugo Ferreira
--
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