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1 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Tim Abbott
|
4d94d4d6f6 |
[schema] Add case-insensitive index on message subject field.
We need to run the schema migration manually using
"CREATE INDEX CONCURRENTLY upper_subject_idx ON zerver_message ((upper(subject)));"
since we need CONCURRENTLY and I seem to recall that doesn't work with South.
Apparently our existing indexes on subject/topic weren't being used in
our narrowing queries, because we do case-insensitive search.
This substantially improves our database performance around
stream+topic narrows. See before and after query plans below from my
test instance.
humbug=# explain analyze SELECT "zerver_message"."id" FROM "zerver_message" WHERE ("zerver_message"."recipient_id" = 38 AND UPPER(zerver_message.subject) = 'TEST' AND "zerver_message"."id" <= 348495 ) ORDER BY "zerver_message"."id" DESC LIMIT 50;
QUERY PLAN
---------------------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=13510.61..13510.71 rows=41 width=4) (actual time=32.952..32.958 rows=2 loops=1)
-> Sort (cost=13510.61..13510.71 rows=41 width=4) (actual time=32.946..32.947 rows=2 loops=1)
Sort Key: id
Sort Method: quicksort Memory: 25kB
-> Bitmap Heap Scan on zerver_message (cost=237.99..13509.51 rows=41 width=4) (actual time=2.357..32.912 rows=2 loops=1)
Recheck Cond: (recipient_id = 38)
Filter: ((id <= 348495) AND (upper((subject)::text) = 'TEST'::text))
-> Bitmap Index Scan on zephyr_message_recipient_id (cost=0.00..237.98 rows=8221 width=0) (actual time=1.178..1.178 rows=10354 loops=1)
Index Cond: (recipient_id = 38)
Total runtime: 33.049 ms
(10 rows)
humbug=# explain analyze SELECT "zerver_message"."id" FROM "zerver_message" WHERE ("zerver_message"."recipient_id" = 38 AND UPPER(zerver_message.subject) = 'TEST' AND "zerver_message"."id" <= 348495 ) ORDER BY "zerver_message"."id" DESC LIMIT 50;
QUERY PLAN
---------------------------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=435.11..435.22 rows=41 width=4) (actual time=4.998..4.999 rows=2 loops=1)
-> Sort (cost=435.11..435.22 rows=41 width=4) (actual time=4.997..4.997 rows=2 loops=1)
Sort Key: id
Sort Method: quicksort Memory: 25kB
-> Bitmap Heap Scan on zerver_message (cost=275.63..434.02 rows=41 width=4) (actual time=4.981..4.984 rows=2 loops=1)
Recheck Cond: ((upper((subject)::text) = 'TEST'::text) AND (recipient_id = 38))
Filter: (id <= 348495)
-> BitmapAnd (cost=275.63..275.63 rows=41 width=0) (actual time=4.954..4.954 rows=0 loops=1)
-> Bitmap Index Scan on upper_subject_idx (cost=0.00..37.38 rows=1744 width=0) (actual time=2.972..2.972 rows=27457 loops=1)
Index Cond: (upper((subject)::text) = 'TEST'::text)
-> Bitmap Index Scan on zephyr_message_recipient_id (cost=0.00..237.98 rows=8221 width=0) (actual time=0.855..0.855 rows=10354 loops=1)
Index Cond: (recipient_id = 38)
Total runtime: 5.049 ms
(13 rows)
(imported from commit 1f4815ccb0691053ff8d505149482dbc74153fb3)
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