我在同一张桌子上使用连接一次获得50行，但需要20秒才能获得50行。
Select Distinct ON (S1.service) S1.account,S1.stid,S1.receiver,S1.identifier,
S1.binfo,S2.dlr_mask,S2.time,S1.msgdata,S1.msg_cost
from sql_sent_sms S1
left join sql_sent_sms S2
on S1.service = S2.service
where S2.time Between :senttime and :endtime
and S1.userid=:userid
Order By S1.service");
我在time , service ,userid参数上创建了索引。
但它没有多大帮助。
我还应该做些什么来加快速度。
这是分析查询的结果
EXPLAIN ANALYZE Select Distinct ON (S1.service) S1.account,S1.stid,S1.receiver,S1.identifier,S1.binfo,S2.dlr_mask,S2.time,S1.msgdata,S1.msg_cost
from sql_sent_sms S1
left join sql_sent_sms S2
on S1.service = S2.service
where S2.time Between '1459759193' and '1459849193'
and S1.userid='10412144'
Order By S1.service , S2.dlr_mask asc limit 50;
QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=56635220.85..56938614.70 rows=50 width=308) (actual time=1.177..1.177 rows=0 loops=1)
-> Unique (cost=56635220.85..57035700.74 rows=66 width=308) (actual time=1.176..1.176 rows=0 loops=1)
-> Sort (cost=56635220.85..56835460.79 rows=80095977 width=308) (actual time=1.176..1.176 rows=0 loops=1)
Sort Key: s1.service, s2.dlr_mask
Sort Method: quicksort Memory: 25kB
-> Nested Loop (cost=1.24..127912.78 rows=80095977 width=308) (actual time=1.166..1.166 rows=0 loops=1)
-> Index Scan using idx_sentmsgbydate on sql_sent_sms s1 (cost=0.43..21247.62 rows=5765 width=292) (actual time=0.035..0.091 rows=34 loops=1)
Index Cond: ((userid)::text = '10412144'::text)
-> Index Only Scan using idx_sentmsgandstauts on sql_sent_sms s2 (cost=0.81..18.45 rows=5 width=126) (actual time=0.030..0.030 rows=0 loops=34)
Index Cond: ((service = (s1.service)::text) AND ("time" >= 1459759193::bigint) AND ("time" <= 1459849193::bigint))
Heap Fetches: 0
Planning time: 2.471 ms
Execution time: 1.269 ms
(13 rows)