PostgreSQL 7.4beta5 vs MySQL 4.0.16 with RT(DBIx::SearchBuilder) - Mailing list pgsql-performance

Dear PostgreSQL gurus,

I really not intend to start a flame war here but i am genuinely
seeking help to retain PostgreSQL as my database for my RT
system.

Few months back i had posted regarding lowering of column names in SQL
being passed to RDBMS by DBIx::SearchBuilder , looks like it was controlled
by a parameter "CASESENSITIVE" changing it to 1 from 0 did help for postgresql
to MySQL it probably does not matter.


But This time its a different situation
The query in Postgresql is taking  6 times more than MySQL

The Query being given gets generated by DBIx::SearchBuilder.
Although i am not sure but i feel modules like DBIx::SearchBuilder which are
supposed to provide RDBMS independent abstraction  are unfortunately
getting test only with MySQL or Oracle otherwise such huge difference in timing
were not possible.



IN MYSQL:
========
mysql>  SELECT DISTINCT main.* FROM Groups main , Principals Principals_1, ACL ACL_2  WHERE
((ACL_2.RightName = 'OwnTicket')OR(ACL_2.RightName = 'SuperUser')) AND  ( (    ACL_2.PrincipalId =
Principals_1.id AND ACL_2.PrincipalType = 'Group' AND (   main.Domain = 'SystemInternal' OR
main.Domain = 'UserDefined' OR main.Domain = 'ACLEquivalence') AND main.id = Principals_1.id) OR (
( (main.Domain = 'RT::Queue-Role' AND main.Instance = 25)  OR ( main.Domain = 'RT::Ticket-Role'
AND main.Instance = 6973)  )  AND main.Type = ACL_2.PrincipalType AND main.id = Principals_1.id) )
AND (ACL_2.ObjectType = 'RT::System'  OR (ACL_2.ObjectType = 'RT::Queue' AND ACL_2.ObjectId = 25)
)  ORDER BY main.Name ASC ;+-------+------------+---------------------------+----------------+-----------+----------+
| id    | Name       | Description               | Domain         | Type      | Instance |
+-------+------------+---------------------------+----------------+-----------+----------+
| 40208 | sales      | Sales team in Delhi       | UserDefined    |           |          |
|     2 | User 1     | ACL equiv. for user 1     | ACLEquivalence | UserEquiv | 1        |
|    11 | User 10    | ACL equiv. for user 10    | ACLEquivalence | UserEquiv | 10       |
|    13 | User 12    | ACL equiv. for user 12    | ACLEquivalence | UserEquiv | 12       |
| 31067 | User 31066 | ACL equiv. for user 31066 | ACLEquivalence | UserEquiv | 31066    |
+-------+------------+---------------------------+----------------+-----------+----------+
5 rows in set (0.94 sec)

mysql>

WHEREAS for PostgreSQL:
rt3=# SELECT version();
 PostgreSQL 7.4beta5 on i686-pc-linux-gnu, compiled by GCC 2.96


rt3=# SELECT DISTINCT main.* FROM Groups main , Principals Principals_1, ACL ACL_2  WHERE
((ACL_2.RightName = 'OwnTicket')OR(ACL_2.RightName = 'SuperUser')) AND  ( (    ACL_2.PrincipalId =
Principals_1.id AND ACL_2.PrincipalType = 'Group' AND (   main.Domain = 'SystemInternal' OR
main.Domain = 'UserDefined' OR main.Domain = 'ACLEquivalence') AND main.id = Principals_1.id) OR (
( (main.Domain = 'RT::Queue-Role' AND main.Instance = 25)  OR ( main.Domain = 'RT::Ticket-Role'
AND main.Instance = 6973)  )  AND main.Type = ACL_2.PrincipalType AND main.id = Principals_1.id) )
AND (ACL_2.ObjectType = 'RT::System'  OR (ACL_2.ObjectType = 'RT::Queue' AND ACL_2.ObjectId = 25)
)  ORDER BY main.Name ASC ;+-------+------------+---------------------------+----------------+-----------+----------+
|  id   |    name    |        description        |     domain     |   type    | instance |
+-------+------------+---------------------------+----------------+-----------+----------+
| 40264 | sales      | Sales team in Delhi       | UserDefined    |           |          |
|     2 | User 1     | ACL equiv. for user 1     | ACLEquivalence | UserEquiv | 1        |
|    11 | User 10    | ACL equiv. for user 10    | ACLEquivalence | UserEquiv | 10       |
|    13 | User 12    | ACL equiv. for user 12    | ACLEquivalence | UserEquiv | 12       |
| 31123 | User 31122 | ACL equiv. for user 31122 | ACLEquivalence | UserEquiv | 31122    |
+-------+------------+---------------------------+----------------+-----------+----------+
(5 rows)
Time: 7281.574 ms
rt3=#

Explain Analyze of Above Query is being given below:

Unique  (cost=4744.06..4744.08 rows=1 width=81) (actual time=6179.789..6179.828 rows=5 loops=1)
   ->  Sort  (cost=4744.06..4744.07 rows=1 width=81) (actual time=6179.785..6179.792 rows=6 loops=1)
         Sort Key: main.name, main.id, main.description, main."domain", main."type", main.instance
         ->  Nested Loop  (cost=1788.68..4744.05 rows=1 width=81) (actual time=584.004..6179.712
         rows=6 loops=1)               Join Filter: (((("inner".principaltype)::text = 'Group'::text) OR
               (("outer"."domain")::text = 'RT::Ticket-Role'::text) OR (("outer"."domain")::text =
               'RT::Queue-Role'::text)) AND ((("inner".principaltype)::text = 'Group'::text) OR
               (("outer".instance)::text = '6973'::text) OR (("outer"."domain")::text =
               'RT::Queue-Role'::text)) AND ((("inner".principaltype)::text = 'Group'::text) OR
               (("outer"."domain")::text = 'RT::Ticket-Role'::text) OR (("outer".instance)::text =
               '25'::text)) AND ((("inner".principaltype)::text = 'Group'::text) OR
               (("outer".instance)::text = '6973'::text) OR (("outer".instance)::text =
               '25'::text)) AND ((("inner".principaltype)::text = 'Group'::text) OR
               (("outer"."type")::text = ("inner".principaltype)::text)) AND
               ((("outer"."domain")::text = 'SystemInternal'::text) OR (("outer"."domain")::text =
               'UserDefined'::text) OR (("outer"."domain")::text = 'ACLEquivalence'::text) OR
               (("outer"."type")::text = ("inner".principaltype)::text)) AND (("inner".principalid
               = "outer".id) OR (("outer"."domain")::text = 'RT::Ticket-Role'::text) OR
               (("outer"."domain")::text = 'RT::Queue-Role'::text)) AND (("inner".principalid =
               "outer".id) OR (("outer".instance)::text = '6973'::text) OR
               (("outer"."domain")::text = 'RT::Queue-Role'::text)) AND (("inner".principalid =
               "outer".id) OR (("outer"."domain")::text = 'RT::Ticket-Role'::text) OR
               (("outer".instance)::text = '25'::text)) AND (("inner".principalid = "outer".id) OR
               (("outer".instance)::text = '6973'::text) OR (("outer".instance)::text =
               '25'::text)) AND (("inner".principalid = "outer".id) OR (("outer"."type")::text =
               ("inner".principaltype)::text)) AND (("outer".id = "outer".id) OR
               (("outer"."type")::text = ("inner".principaltype)::text)) AND (("inner".principalid
               = "outer".id) OR ("outer".id = "outer".id)) AND ((("inner".principaltype)::text =
               'Group'::text) OR ("outer".id = "outer".id)))               ->  Merge Join  (cost=1788.68..4735.71
rows=1width=85) (actual 
               time=583.804..1187.448 rows=20153 loops=1)                     Merge Cond: ("outer".id = "inner".id)
                     Join Filter: ((("inner".id = "outer".id) OR (("inner"."domain")::text =
                     'RT::Ticket-Role'::text) OR (("inner"."domain")::text =
                     'RT::Queue-Role'::text)) AND (("inner".id = "outer".id) OR
                     (("inner".instance)::text = '6973'::text) OR (("inner"."domain")::text =
                     'RT::Queue-Role'::text)) AND (("inner".id = "outer".id) OR
                     (("inner"."domain")::text = 'RT::Ticket-Role'::text) OR
                     (("inner".instance)::text = '25'::text)) AND (("inner".id = "outer".id) OR
                     (("inner".instance)::text = '6973'::text) OR (("inner".instance)::text =
                     '25'::text)) AND ((("inner"."domain")::text = 'SystemInternal'::text) OR
                     (("inner"."domain")::text = 'UserDefined'::text) OR (("inner"."domain")::text
                     = 'ACLEquivalence'::text) OR ("inner".id = "outer".id)))                     ->  Index Scan using
principals_pkeyon principals principals_1  
                     (cost=0.00..2536.49 rows=82221 width=4) (actual time=0.087..169.725
                     rows=64626 loops=1)                     ->  Sort  (cost=1788.68..1797.99 rows=3726 width=81)
(actual
                     time=583.624..625.604 rows=20153 loops=1)                           Sort Key: main.id
                           ->  Index Scan using groups_domain, groups_domain, groups_domain,
                           groups_lower_instance, groups_domain on groups main
                           (cost=0.00..1567.66 rows=3726 width=81) (actual time=0.132..449.240
                           rows=20153 loops=1)                                 Index Cond: ((("domain")::text =
'SystemInternal'::text)OR 
                                 (("domain")::text = 'UserDefined'::text) OR (("domain")::text =
                                 'ACLEquivalence'::text) OR ((instance)::text = '6973'::text) OR
                                 (("domain")::text = 'RT::Queue-Role'::text))                                 Filter:
(((("domain")::text= 'SystemInternal'::text) OR 
                                 (("domain")::text = 'UserDefined'::text) OR (("domain")::text =
                                 'ACLEquivalence'::text) OR (("domain")::text =
                                 'RT::Ticket-Role'::text) OR (("domain")::text =
                                 'RT::Queue-Role'::text)) AND ((("domain")::text =
                                 'SystemInternal'::text) OR (("domain")::text =
                                 'UserDefined'::text) OR (("domain")::text =
                                 'ACLEquivalence'::text) OR (("domain")::text =
                                 'RT::Ticket-Role'::text) OR ((instance)::text = '25'::text)) AND
                                 ((("domain")::text = 'SystemInternal'::text) OR (("domain")::text
                                 = 'UserDefined'::text) OR (("domain")::text =
                                 'ACLEquivalence'::text) OR ((instance)::text = '6973'::text) OR
                                 ((instance)::text = '25'::text)))               ->  Index Scan using acl_objectid,
acl_objecttypeon acl acl_2  (cost=0.00..8.03 
               rows=3 width=13) (actual time=0.032..0.138 rows=6 loops=20153)                     Index Cond:
((objectid= 25) OR ((objecttype)::text = 'RT::System'::text)) 
                     Filter: ((((rightname)::text = 'OwnTicket'::text) OR ((rightname)::text =
                     'SuperUser'::text)) AND (((objecttype)::text = 'RT::Queue'::text) OR
                     ((objecttype)::text = 'RT::System'::text))) Total runtime: 6183.155 ms [ 6 secs approx ]
(18 rows)

Sincerely Looking Forward to a Help
Regds
Mallah








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