nest loop
最近更新时间: 2025-02-18 16:02:00
postgres=# explain select * from t1,t2 where t1.f1=t2.f1 and t2.f2=1;
QUERY PLAN
---------------------------------------------------------------------------------
Remote Fast Query Execution (cost=0.00..0.00 rows=0 width=0)
Node/s: dn001, dn002
-> Nested Loop (cost=0.70..8.75 rows=1 width=45)
-> Index Scan using t2_f2_idx on t2 (cost=0.28..4.30 rows=1 width=8)
Index Cond: (f2 = 1)
-> Index Scan using tf_f1_idx on t1 (cost=0.42..4.44 rows=1 width=37)
Index Cond: (f1 = t2.f1)
(7 rows)
postgres=#注意：
驱动表要小表。