Query puts 7.3.4 on endless loop but 7.4beta5 is fine.

ok this time it constructs a query which puts 7.3.4 on a infinite loop
but 7.4b5 is able to come out of it.

since it may be of interest to the pgsql people i am Ccing it to the
pgsql-performance list i hope its ok.

Pgsql 7.3.4 on an endless loop:

SELECT DISTINCT main.* FROM ((((Tickets main JOIN Groups as Groups_1 ON ( main.id =
Groups_1.Instance)) JOIN Principals as Principals_2 ON ( Groups_1.id = Principals_2.ObjectId))
JOIN CachedGroupMembers as CachedGroupMembers_3 ON ( Principals_2.id =
CachedGroupMembers_3.GroupId)) JOIN Users as Users_4 ON ( CachedGroupMembers_3.MemberId =
Users_4.id)) WHERE ((main.EffectiveId = main.id)) AND ((main.Type = 'ticket')) AND ( ( (
(Users_4.EmailAddress = 'mallah_rajesh(at)yahoo(dot)com')AND(Groups_1.Domain =
'RT::Ticket-Role')AND(Groups_1.Type = 'Requestor')AND(Principals_2.PrincipalType = 'Group') ) )
AND ( (main.Status = 'new')OR(main.Status = 'open') ) ) ORDER BY main.Priority DESC LIMIT 10

But 7.4 beta5 seems to be able to handle it:

SELECT DISTINCT main.* FROM ((((Tickets main JOIN Groups as Groups_1 ON ( main.id =
Groups_1.Instance)) JOIN Principals as Principals_2 ON ( Groups_1.id = Principals_2.ObjectId))
JOIN CachedGroupMembers as CachedGroupMembers_3 ON ( Principals_2.id =
CachedGroupMembers_3.GroupId)) JOIN Users as Users_4 ON ( CachedGroupMembers_3.MemberId =
Users_4.id)) WHERE ((main.EffectiveId = main.id)) AND ((main.Type = 'ticket')) AND ( ( (
(Users_4.EmailAddress = 'mallah_rajesh(at)yahoo(dot)com')AND(Groups_1.Domain =
'RT::Ticket-Role')AND(Groups_1.Type = 'Requestor')AND(Principals_2.PrincipalType = 'Group') ) )
AND ( (main.Status = 'new')OR(main.Status = 'open') ) ) ORDER BY main.Priority DESC LIMIT 10; id | effectiveid | queue | type | issuestatement | resolution | owner | subject
| initialpriority | finalpriority | priority | timeestimated | timeworked | status | timeleft
| told | starts | started | due | resolved |
lastupdatedby | lastupdated | creator | created | disabled------+-------------+-------+--------+----------------+------------+-------+-------------------------+-----------------+---------------+----------+---------------+------------+--------+----------+------+---------------------+---------------------+---------------------+---------------------+---------------+---------------------+---------+---------------------+---------- 13 | 13 | 23 | ticket | 0 | 0 | 31122 | General Discussion
| 0 | 0 | 0 | 0 | 0 | new | 0
| | 1970-01-01 00:00:00 | 1970-01-01 00:00:00 | 1970-01-01 00:00:00 | 1970-01-01 00:00:00
| 31122 | 2001-11-22 04:19:10 | 31122 | 2001-11-22 04:19:07 | 0 6018 | 6018 | 19 | ticket | 0 | 0 | 10 | EYP Prospective
Clients | 0 | 0 | 0 | 0 | 0 | new |
0 | | 1970-01-01 00:00:00 | 1970-01-01 00:00:00 | 2002-09-11 18:29:37 | 1970-01-01
00:00:00 | 31122 | 2002-09-11 18:29:39 | 31122 | 2002-09-11 18:29:37 | 0 6336 | 6336 | 19 | ticket | 0 | 0 | 10 | EYP Prospective
Clients | 0 | 0 | 0 | 0 | 0 | new |
0 | | 1970-01-01 00:00:00 | 1970-01-01 00:00:00 | 2002-09-20 12:31:02 | 1970-01-01
00:00:00 | 31122 | 2002-09-20 12:31:09 | 31122 | 2002-09-20 12:31:02 | 0 6341 | 6341 | 19 | ticket | 0 | 0 | 10 | IP Prospective
Clients | 0 | 0 | 0 | 0 | 0 | new |
0 | | 1970-01-01 00:00:00 | 1970-01-01 00:00:00 | 2002-09-20 14:34:25 | 1970-01-01
00:00:00 | 31122 | 2002-09-20 14:34:26 | 31122 | 2002-09-20 14:34:25 | 0(4 rows)

Time: 900.930 ms

With The explain analyze below:

rt3=# explain analyze SELECT DISTINCT main.* FROM ((((Tickets main JOIN Groups as Groups_1 ON (
main.id = Groups_1.Instance)) JOIN Principals as Principals_2 ON ( Groups_1.id =
Principals_2.ObjectId)) JOIN CachedGroupMembers as CachedGroupMembers_3 ON ( Principals_2.id =
CachedGroupMembers_3.GroupId)) JOIN Users as Users_4 ON ( CachedGroupMembers_3.MemberId =
Users_4.id)) WHERE ((main.EffectiveId = main.id)) AND ((main.Type = 'ticket')) AND ( ( (
(Users_4.EmailAddress = 'mallah_rajesh(at)yahoo(dot)com')AND(Groups_1.Domain =
'RT::Ticket-Role')AND(Groups_1.Type = 'Requestor')AND(Principals_2.PrincipalType = 'Group') ) )
AND ( (main.Status = 'new')OR(main.Status = 'open') ) ) ORDER BY main.Priority DESC LIMIT 10; QUERY
PLAN------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Limit (cost=582.27..582.34 rows=1 width=164) (actual time=854.302..854.433 rows=4 loops=1)
-> Unique (cost=582.27..582.34 rows=1 width=164) (actual time=854.297..854.418 rows=4 loops=1)
-> Sort (cost=582.27..582.28 rows=1 width=164) (actual time=854.294..854.303 rows=8
loops=1) Sort Key: main.priority, main.id, main.effectiveid, main.queue, main."type",
main.issuestatement, main.resolution, main."owner", main.subject,
main.initialpriority, main.finalpriority, 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=476.18..582.26 rows=1 width=164) (actual time=853.025..854.056
rows=8 loops=1) Hash Cond: ("outer".groupid = "inner".id)
-> Nested Loop (cost=0.00..105.97 rows=21 width=4) (actual
time=0.372..1.073 rows=37 loops=1) -> Index Scan using users4 on users users_4 (cost=0.00..3.99 rows=2
width=4) (actual time=0.182..0.188 rows=1 loops=1) Index Cond: ((emailaddress)::text = 'mallah_rajesh(at)yahoo(dot)com'::text)
-> Index Scan using cachedgroupmembers2 on cachedgroupmembers
cachedgroupmembers_3 (cost=0.00..50.81 rows=14 width=8) (actual
time=0.165..0.703 rows=37 loops=1) Index Cond: (cachedgroupmembers_3.memberid = "outer".id)
-> Hash (cost=476.17..476.17 rows=1 width=168) (actual
time=852.267..852.267 rows=0 loops=1) -> Nested Loop (cost=0.00..476.17 rows=1 width=168) (actual
time=0.684..842.401 rows=3209 loops=1) -> Nested Loop (cost=0.00..471.54 rows=1 width=168) (actual
time=0.571..704.492 rows=3209 loops=1) -> Seq Scan on tickets main (cost=0.00..465.62 rows=1
width=164) (actual time=0.212..87.100 rows=3209 loops=1) Filter: ((effectiveid = id) AND (("type")::text =
'ticket'::text) AND (((status)::text = 'new'::text)
OR ((status)::text = 'open'::text))) -> Index Scan using groups1 on groups groups_1
(cost=0.00..5.90 rows=1 width=12) (actual time=0.158..0.168
rows=1 loops=3209) Index Cond: (((groups_1."domain")::text =
'RT::Ticket-Role'::text) AND (("outer".id)::text =
(groups_1.instance)::text) AND
((groups_1."type")::text = 'Requestor'::text)) -> Index Scan using principals2 on principals principals_2
(cost=0.00..4.62 rows=1 width=8) (actual time=0.019..0.022 rows=1
loops=3209) Index Cond: ("outer".id = principals_2.objectid)
Filter: ((principaltype)::text = 'Group'::text)
Total runtime: 855.472 ms
(22 rows)

Time: 895.739 ms
rt3=#

> http://backpan.cpan.org/authors/id/J/JE/JESSE/DBIx-SearchBuilder-0.90.tar.gz
>
>
> On Thu, Oct 30, 2003 at 01:57:31AM +0530, mallah(at)trade-india(dot)com wrote:
>> >
>> >
>> >
>> > On Thu, Oct 30, 2003 at 01:30:26AM +0530, mallah(at)trade-india(dot)com wrote:
>> >>
>> >> Dear Jesse,
>> >>
>> >> I really want to add a Pg specific better query builder
>> >> the generic one is messing with postgresql.
>> >
>> > I've removed the CC to ivan, to my knowledge, he has nothing to do with SB these days
>> > anymore.
>> >
>> >
>> >> i think i have to work in :
>> >> DBIx/SearchBuilder/Handle/Pg.pm
>> >>
>> >> i hope u read my recent emails to pgsql-performance list.
>>
>> Yes.
>>
>>
>>
>> >>
>> > And I hope you read my reply. There _is_ a postgres specific query builder. And there was a
>> > bug in 0.90 that caused a possible endless loop. The bugfix disabled some of the
>> > optimization. If you can tell me that 0.90 improves your performance (as it generated more
>> > correct queries for pg) then we can work on just fixing the little bug.
>>
>> where is .90 ? i dont see it in
>>
>> http://www.fsck.com/pub/rt/devel/
>>
>>
>> regds
>> mallah.
>>
>>
>> >
>> >
>> >
>> >> =================================================================================== # this
>> >> code is all hacky and evil. but people desperately want _something_ and I'm # super tired.
>> >> refactoring gratefully appreciated.
>> >> ===================================================================================
>> >>
>> >> sub _BuildJoins {
>> >> my $self = shift;
>> >> my $sb = shift;
>> >> my %seen_aliases;
>> >>
>> >> $seen_aliases{'main'} = 1;
>> >>
>> >> my $join_clause =$sb->{'table'} . " main " ;
>> >>
>> >> my @keys = ( keys %{ $sb->{'left_joins'} } );
>> >>
>> >> while ( my $join = shift @keys ) {
>> >> if ( $seen_aliases{ $sb->{'left_joins'}{$join}{'depends_on'} } ) {
>> >> $join_clause = "(" . $join_clause;
>> >> $join_clause .= $sb->{'left_joins'}{$join}{'alias_string'} . " ON (";
>> >> $join_clause .=
>> >> join ( ') AND( ', values %{ $sb->{'left_joins'}{$join}{'criteria'} } );
>> >> $join_clause .= ")) ";
>> >>
>> >> $seen_aliases{$join} = 1;
>> >> }
>> >> else {
>> >> push ( @keys, $join );
>> >> }
>> >>
>> >> }
>> >> return (
>> >> join ( ", ", ($join_clause, @{ $sb->{'aliases'} }))) ;
>> >>
>> >> }
>> >>
>> >>
>> >>
>> >>
>> >>
>> >> -----------------------------------------
>> >> Over 1,00,000 exporters are waiting for your order! Click below to get in touch with
>> >> leading Indian exporters listed in the premier
>> >> trade directory Exporters Yellow Pages.
>> >> http://www.trade-india.com/dyn/gdh/eyp/
>> >>
>> >>
>> >
>> > --
>> > jesse reed vincent -- root(at)eruditorum(dot)org -- jesse(at)fsck(dot)com
>> > 70EBAC90: 2A07 FC22 7DB4 42C1 9D71 0108 41A3 3FB3 70EB AC90
>> >
>> > . . . when not in doubt, get in doubt. -- Old Discordian Proveb
>>
>>
>> -----------------------------------------
>> Over 1,00,000 exporters are waiting for your order! Click below to get in touch with leading
>> Indian exporters listed in the premier
>> trade directory Exporters Yellow Pages.
>> http://www.trade-india.com/dyn/gdh/eyp/
>>
>>
>
> --
> jesse reed vincent -- root(at)eruditorum(dot)org -- jesse(at)fsck(dot)com
> 70EBAC90: 2A07 FC22 7DB4 42C1 9D71 0108 41A3 3FB3 70EB AC90
>
> . . . when not in doubt, get in doubt. -- Old Discordian Proveb

-----------------------------------------
Over 1,00,000 exporters are waiting for your order! Click below to get
in touch with leading Indian exporters listed in the premier
trade directory Exporters Yellow Pages.
http://www.trade-india.com/dyn/gdh/eyp/