Query planner making bad decisions

I'm running version 8.1.11 on SLES 10 SP2. I'm trying to improve this
query and unfortunately I cannot change the application. For some
reason the planner is making a bad decision sometimes after an analyze
of table objectcustomfieldvalues.

The query is:
SELECT DISTINCT main.* FROM Tickets main JOIN CustomFields
CustomFields_1 ON ( CustomFields_1.Name = 'QA Origin' ) JOIN
CustomFields CustomFields_3 ON (CustomFields_3.Name = 'QA Group Code' )
JOIN ObjectCustomFieldValues ObjectCustomFieldValues_4 ON
(ObjectCustomFieldValues_4.ObjectId = main.id ) AND (
ObjectCustomFieldValues_4.Disabled = '0' ) AND
(ObjectCustomFieldValues_4.ObjectType = 'RT::Ticket' ) AND (
ObjectCustomFieldValues_4.CustomField = CustomFields_3.id ) JOIN
ObjectCustomFieldValues ObjectCustomFieldValues_2 ON (
ObjectCustomFieldValues_2.Disabled = '0' ) AND
(ObjectCustomFieldValues_2.ObjectId = main.id ) AND (
ObjectCustomFieldValues_2.CustomField = CustomFields_1.id ) AND
(ObjectCustomFieldValues_2.ObjectType = 'RT::Ticket' ) WHERE
(main.Status != 'deleted') AND (main.Queue = '60' AND
ObjectCustomFieldValues_2.Content LIKE '%Patient Sat Survey%' AND
ObjectCustomFieldValues_4.Content LIKE'%MOT%') AND (main.EffectiveId =
main.id) AND (main.Type = 'ticket') ORDER BY main.id ASC;

Here is the query run in 12379.816 ms:

Unique (cost=1560.06..1560.12 rows=1 width=181) (actual
time=12379.573..12379.642 rows=13 loops=1)
-> Sort (cost=1560.06..1560.06 rows=1 width=181) (actual
time=12379.568..12379.586 rows=13 loops=1)
Sort Key: main.id, main.effectiveid, main.queue, main."type",
main.issuestatement, main.resolution, main."owner", main.subject,
main.initialpriority, main.finalpriority, main.priority,
main.timeestimated, main.timeworked, main.status, main.timeleft,
main.told, main.starts, main.started, main.due, main.resolved,
main.lastupdatedby, main.lastupdated, main.creator, main.created,
main.disabled
-> Nested Loop (cost=0.00..1560.05 rows=1 width=181) (actual
time=9081.782..12379.303 rows=13 loops=1)
Join Filter: ("outer".objectid = "inner".id)
-> Nested Loop (cost=0.00..849.90 rows=1 width=8)
(actual time=9059.881..12052.548 rows=13 loops=1)
Join Filter: ("outer".objectid = "inner".objectid)
-> Nested Loop (cost=0.00..424.19 rows=1 width=4)
(actual time=0.274..26.660 rows=1575 loops=1)
-> Index Scan using customfields_pkey on
customfields customfields_1 (cost=0.00..16.41 rows=1 width=4) (actual
time=0.228..0.371 rows=1 loops=1)
Filter: ((name)::text = 'QA Origin'::text)
-> Index Scan using ticketcustomfieldvalues2
on objectcustomfieldvalues objectcustomfieldvalues_2 (cost=0.00..407.76
rows=1 width=8) (actual time=0.039..21.243 rows=1575 loops=1)
Index Cond:
(objectcustomfieldvalues_2.customfield = "outer".id)
Filter: ((disabled = 0) AND
((objecttype)::text = 'RT::Ticket'::text) AND ((content)::text ~~
'%Patient Sat Survey%'::text))
-> Nested Loop (cost=0.00..424.99 rows=58
width=4) (actual time=5.188..7.605 rows=18 loops=1575)
-> Index Scan using customfields_pkey on
customfields customfields_3 (cost=0.00..16.41 rows=1 width=4) (actual
time=0.235..0.419 rows=1 loops=1575)
Filter: ((name)::text = 'QA Group
Code'::text)
-> Index Scan using ticketcustomfieldvalues2
on objectcustomfieldvalues objectcustomfieldvalues_4 (cost=0.00..407.76
rows=65 width=8) (actual time=4.947..7.130 rows=18 loops=1575)
Index Cond:
(objectcustomfieldvalues_4.customfield = "outer".id)
Filter: ((disabled = 0) AND
((objecttype)::text = 'RT::Ticket'::text) AND ((content)::text ~~
'%MOT%'::text))
-> Index Scan using tickets1 on tickets main
(cost=0.00..709.77 rows=30 width=181) (actual time=0.020..17.104
rows=5743 loops=13)
Index Cond: (queue = 60)
Filter: (((status)::text <> 'deleted'::text) AND
(effectiveid = id) AND (("type")::text = 'ticket'::text))
Total runtime: 12379.816 ms
(23 rows)

select attname,n_distinct from pg_stats where tablename='tickets';
attname | n_distinct
-----------------+------------
id | -1
effectiveid | -0.968462
queue | 37
type | 1
issuestatement | 1
resolution | 1
owner | 123
subject | -0.885148
initialpriority | 12
finalpriority | 9
priority | 43
timeestimated | 5
timeworked | 5
status | 6
timeleft | 3
told | -0.128088
starts | 60
started | -0.862352
due | 1270
resolved | -0.94381
lastupdatedby | 366
lastupdated | -0.98511
creator | 1054
created | -0.965858
disabled | 1
(25 rows)

select attname,n_distinct from pg_stats where tablename='customfields';
attname | n_distinct
---------------+------------
id | -1
name | -0.83855
type | 3
description | -0.202636
sortorder | -0.110379
creator | 4
created | -0.739703
lastupdatedby | 4
lastupdated | -0.78089
disabled | 2
lookuptype | 1
repeated | 1
pattern | 1
maxvalues | 2
(14 rows)

select attname,n_distinct from pg_stats where
tablename='objectcustomfieldvalues';
attname | n_distinct
-----------------+------------
id | -1
objectid | 95048
customfield | 543
content | 30209
creator | 115
created | -0.268605
lastupdatedby | 115
lastupdated | -0.26863
objecttype | 1
largecontent | -1
contenttype | 1
contentencoding | 2
sortorder | 1
disabled | 2
(14 rows)

If I now analyze objectcustomfieldvalues the query now takes 51747.341 ms:

Unique (cost=1564.95..1565.02 rows=1 width=181) (actual
time=51747.087..51747.152 rows=13 loops=1)
-> Sort (cost=1564.95..1564.95 rows=1 width=181) (actual
time=51747.083..51747.097 rows=13 loops=1)
Sort Key: main.id, main.effectiveid, main.queue, main."type",
main.issuestatement, main.resolution, main."owner", main.subject,
main.initialpriority, main.finalpriority, main.priority,
main.timeestimated, main.timeworked, main.status, main.timeleft,
main.told, main.starts, main.started, main.due, main.resolved,
main.lastupdatedby, main.lastupdated, main.creator, main.created,
main.disabled
-> Nested Loop (cost=0.00..1564.94 rows=1 width=181) (actual
time=38871.343..51746.920 rows=13 loops=1)
Join Filter: ("inner".objectid = "outer".id)
-> Nested Loop (cost=0.00..1136.77 rows=1 width=185)
(actual time=7.772..39862.238 rows=1548 loops=1)
Join Filter: ("outer".objectid = "inner".id)
-> Nested Loop (cost=0.00..426.63 rows=1 width=4)
(actual time=0.266..27.745 rows=1575 loops=1)
-> Index Scan using customfields_pkey on
customfields customfields_1 (cost=0.00..16.41 rows=1 width=4) (actual
time=0.219..0.404 rows=1 loops=1)
Filter: ((name)::text = 'QA Origin'::text)
-> Index Scan using ticketcustomfieldvalues2
on objectcustomfieldvalues objectcustomfieldvalues_2 (cost=0.00..410.20
rows=1 width=8) (actual time=0.040..22.006 rows=1575 loops=1)
Index Cond:
(objectcustomfieldvalues_2.customfield = "outer".id)
Filter: ((disabled = 0) AND
((objecttype)::text = 'RT::Ticket'::text) AND ((content)::text ~~
'%Patient Sat Survey%'::text))
-> Index Scan using tickets1 on tickets main
(cost=0.00..709.77 rows=30 width=181) (actual time=0.015..17.164
rows=5743 loops=1575)
Index Cond: (queue = 60)
Filter: (((status)::text <> 'deleted'::text)
AND (effectiveid = id) AND (("type")::text = 'ticket'::text))
-> Nested Loop (cost=0.00..427.44 rows=58 width=4)
(actual time=5.207..7.646 rows=18 loops=1548)
-> Index Scan using customfields_pkey on
customfields customfields_3 (cost=0.00..16.41 rows=1 width=4) (actual
time=0.242..0.434 rows=1 loops=1548)
Filter: ((name)::text = 'QA Group Code'::text)
-> Index Scan using ticketcustomfieldvalues2 on
objectcustomfieldvalues objectcustomfieldvalues_4 (cost=0.00..410.20
rows=66 width=8) (actual time=4.958..7.154 rows=18 loops=1548)
Index Cond:
(objectcustomfieldvalues_4.customfield = "outer".id)
Filter: ((disabled = 0) AND
((objecttype)::text = 'RT::Ticket'::text) AND ((content)::text ~~
'%MOT%'::text))
Total runtime: 51747.341 ms
(23 rows)

select attname,n_distinct from pg_stats where
tablename='objectcustomfieldvalues';
attname | n_distinct
-----------------+------------
id | -1
objectid | 95017
customfield | 539
content | 30287
creator | 114
created | -0.268403
lastupdatedby | 114
lastupdated | -0.268809
objecttype | 1
largecontent | -1
contenttype | 1
contentencoding | 2
sortorder | 1
disabled | 2
(14 rows)

Even better yet, if I turn off enable_nestloop the query runs in
3499.970 ms:

Unique (cost=53860.11..53860.18 rows=1 width=181) (actual
time=3499.614..3499.684 rows=13 loops=1)
-> Sort (cost=53860.11..53860.11 rows=1 width=181) (actual
time=3499.608..3499.627 rows=13 loops=1)
Sort Key: main.id, main.effectiveid, main.queue, main."type",
main.issuestatement, main.resolution, main."owner", main.subject,
main.initialpriority, main.finalpriority, main.priority,
main.timeestimated, main.timeworked, main.status, main.timeleft,
main.told, main.starts, main.started, main.due, main.resolved,
main.lastupdatedby, main.lastupdated, main.creator, main.created,
main.disabled
-> Hash Join (cost=27240.41..53860.10 rows=1 width=181)
(actual time=3429.166..3499.538 rows=13 loops=1)
Hash Cond: ("outer".objectid = "inner".id)
-> Merge Join (cost=0.00..26619.39 rows=58 width=4)
(actual time=1666.503..1736.814 rows=18 loops=1)
Merge Cond: ("outer".id = "inner".customfield)
-> Index Scan using customfields_pkey on
customfields customfields_3 (cost=0.00..16.41 rows=1 width=4) (actual
time=0.221..0.410 rows=1 loops=1)
Filter: ((name)::text = 'QA Group Code'::text)
-> Index Scan using ticketcustomfieldvalues2 on
objectcustomfieldvalues objectcustomfieldvalues_4 (cost=0.00..26514.04
rows=35342 width=8) (actual time=98.035..1736.277 rows=44 loops=1)
Filter: ((disabled = 0) AND
((objecttype)::text = 'RT::Ticket'::text) AND ((content)::text ~~
'%MOT%'::text))
-> Hash (cost=27240.40..27240.40 rows=1 width=185)
(actual time=1762.572..1762.572 rows=1548 loops=1)
-> Hash Join (cost=26530.47..27240.40 rows=1
width=185) (actual time=1728.887..1758.147 rows=1548 loops=1)
Hash Cond: ("outer".id = "inner".objectid)
-> Index Scan using tickets1 on tickets
main (cost=0.00..709.77 rows=30 width=181) (actual time=0.024..17.550
rows=5743 loops=1)
Index Cond: (queue = 60)
Filter: (((status)::text <>
'deleted'::text) AND (effectiveid = id) AND (("type")::text =
'ticket'::text))
-> Hash (cost=26530.47..26530.47 rows=1
width=4) (actual time=1728.787..1728.787 rows=1575 loops=1)
-> Merge Join (cost=0.00..26530.47
rows=1 width=4) (actual time=1493.343..1726.020 rows=1575 loops=1)
Merge Cond: ("outer".id =
"inner".customfield)
-> Index Scan using
customfields_pkey on customfields customfields_1 (cost=0.00..16.41
rows=1 width=4) (actual time=0.237..0.429 rows=1 loops=1)
Filter: ((name)::text = 'QA
Origin'::text)
-> Index Scan using
ticketcustomfieldvalues2 on objectcustomfieldvalues
objectcustomfieldvalues_2 (cost=0.00..26514.04 rows=1 width=8) (actual
time=1493.091..1721.155 rows=1575 loops=1)
Filter: ((disabled = 0) AND
((objecttype)::text = 'RT::Ticket'::text) AND ((content)::text ~~
'%Patient Sat Survey%'::text))
Total runtime: 3499.970 ms
(25 rows)

Is there anything I can do to improve this?

~Cory Coager

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