我有一個這樣的查詢,它使用call_id上的索引,而如果我在值中添加_,那麼它會從索引搜索更改爲seq搜索。postgres中的特殊字符_
explain analyze
DELETE
FROM completedcalls
WHERE call_id like '[email protected]';
QUERY PLAN
--------------------------------------------------------------------------------------------------------------------------------
Delete on completedcalls (cost=0.00..8.67 rows=1 width=6) (actual time=0.036..0.036 rows=0 loops=1)
-> Index Scan using i_call_id on completedcalls (cost=0.00..8.67 rows=1 width=6) (actual time=0.034..0.034 rows=0 loops=1)
Index Cond: ((call_id)::text = '[email protected]'::text)
Filter: ((call_id)::text ~~ '[email protected]'::text)
Total runtime: 0.069 ms
(5 rows)
本聲明:
explain analyze
DELETE
FROM completedcalls
WHERE call_id like '[email protected]_1';
返回此執行計劃:
QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------
Delete on completedcalls (cost=0.00..39548.64 rows=84 width=6) (actual time=194.313..194.313 rows=0 loops=1)
-> Seq Scan on completedcalls (cost=0.00..39548.64 rows=84 width=6) (actual time=194.310..194.310 rows=0 loops=1)
Filter: ((call_id)::text ~~ '[email protected]_1'::text)
Total runtime: 194.349 ms
(4 rows)
我的問題是如何在查詢逃避這些字符。在Python中使用psycopg2。
爲什麼你首先使用'LIKE'?顯然你不想要一個通配符搜索,而是一個平等條件。所以你應該使用'='而不是'LIKE' –