可能您沒有爲繼承表設置約束,或者您使用參數化查詢。
CREATE TABLE a (id serial PRIMARY KEY, ts timestamp);
CREATE INDEX a_ts ON a (ts);
CREATE TABLE a_2010 (CONSTRAINT data_2011_check CHECK (ts >= '2010-01-01 00:00:00'::timestamp AND ts < '2011-01-01 00:00:00'::timestamp)) INHERITS (a);
CREATE TABLE a_2011 (CONSTRAINT data_2012_check CHECK (ts >= '2011-01-01 00:00:00'::timestamp AND ts < '2012-01-01 00:00:00'::timestamp)) INHERITS (a);
CREATE TABLE a_2012 (CONSTRAINT data_2013_check CHECK (ts >= '2012-01-01 00:00:00'::timestamp AND ts < '2013-01-01 00:00:00'::timestamp)) INHERITS (a);
CREATE TABLE a_2013 (CONSTRAINT data_2014_check CHECK (ts >= '2013-01-01 00:00:00'::timestamp AND ts < '2014-01-01 00:00:00'::timestamp)) INHERITS (a);
CREATE INDEX a_ts_2010 ON a_2010 (ts);
CREATE INDEX a_ts_2011 ON a_2011 (ts);
CREATE INDEX a_ts_2012 ON a_2012 (ts);
CREATE INDEX a_ts_2013 ON a_2013 (ts);
之後,你可以看到postgresql檢查通過約束繼承表。約束必須不重疊。
EXPLAIN ANALYZE SELECT * FROM a WHERE ts = '2011-02-01 00:00:00';
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------
Append (cost=0.00..14.79 rows=11 width=12) (actual time=0.006..0.006 rows=0 loops=1)
-> Seq Scan on a (cost=0.00..0.00 rows=1 width=12) (actual time=0.003..0.003 rows=0 loops=1)
Filter: (ts = '2011-02-01 00:00:00'::timestamp without time zone)
-> Bitmap Heap Scan on a_2011 (cost=4.23..14.79 rows=10 width=12) (actual time=0.003..0.003 rows=0 loops=1)
Recheck Cond: (ts = '2011-02-01 00:00:00'::timestamp without time zone)
-> Bitmap Index Scan on a_ts_2011 (cost=0.00..4.23 rows=10 width=0) (actual time=0.003..0.003 rows=0 loops=1)
Index Cond: (ts = '2011-02-01 00:00:00'::timestamp without time zone)
Planning time: 1.148 ms
Execution time: 0.046 ms
(9 rows)