timeout on Bugtask:+Index in subscription lookups

[Andreas Hasenack]

When trying to view this bug:

https://bugs.launchpad.net/ubuntu/+source/shadow/+bug/523896

I get repeated timeouts. Some of the OOPSes:
https://oops.canonical.com/?oopsid=OOPS-4cbdd7d701d18d94e02c14d775a4c779
https://oops.canonical.com/?oopsid=OOPS-8a43a2ec51e6e294639cf74e8ff83155

[Robert Collins (lifeless)]

slow SQL:
                                                                                    QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Unique (cost=159.03..159.04 rows=1 width=763) (actual time=3892.866..3892.888 rows=1 loops=1)
   -> Sort (cost=159.03..159.04 rows=1 width=763) (actual time=3892.864..3892.864 rows=26 loops=1)
         Sort Key: person.name, bugsubscription.person
         Sort Method: quicksort Memory: 38kB
         -> Nested Loop (cost=0.00..159.02 rows=1 width=763) (actual time=709.710..3892.594 rows=26 loops=1)
               -> Nested Loop (cost=0.00..155.07 rows=1 width=32) (actual time=709.665..3892.042 rows=26 loops=1)
                     -> Nested Loop (cost=0.00..105.38 rows=101 width=32) (actual time=0.085..512.618 rows=158602 loops=1)
                           -> Index Scan using teamparticipation_person_idx on teamparticipation (cost=0.00..5.01 rows=2 width=4) (actual time=0.020..0.110 rows=30 loops=1)
                                 Index Cond: (person = 1191103)
                           -> Index Scan using bugsubscription_person_idx on bugsubscription (cost=0.00..49.76 rows=34 width=28) (actual time=0.029..14.230 rows=5287 loops=30)
                                 Index Cond: (person = teamparticipation.team)
                     -> Index Scan using bug_pkey on bug (cost=0.00..0.48 rows=1 width=4) (actual time=0.021..0.021 rows=0 loops=158602)
                           Index Cond: (id = bugsubscription.bug)
                           Filter: ((id = 523896) OR (duplicateof = 523896))
               -> Index Scan using person_pkey on person (cost=0.00..3.93 rows=1 width=735) (actual time=0.014..0.014 rows=1 loops=26)
                     Index Cond: (id = bugsubscription.person)
 Total runtime: 3893.299 ms

[Launchpad QA Bot (lpqabot)]

Fixed in stable r16140 <http://bazaar.launchpad.net/~launchpad-pqm/launchpad/stable/revision/16140>.