Hi all,
I have a question about "explain" output.
Could someone teach me ?
Let a and b tables such that
create table a ( int4 pkey primary key, .... );
create table b ( int4 key1, int2 key2, ...., primary key (key1,key2) );
Table a has 15905 rows and table b has 25905 rows.
For the following query
select a.pkey, b.key2 from a, b where b.key1 = 1369 and a.pkey = b.key1;
"explain" shows
NOTICE: QUERY PLAN:
Nested Loop (cost=6.19 rows=3 width=10) -> Index Scan using b_pkey on b on b (cost=2.09 rows=2 width=6) -> Index
Scanusing a_pkey on a on a (cost=2.05 rows=15905 width=4)
What does "rows=15905" of InnerPlan mean ?
Is "rows=3" of Nested Loop irrelevant to "rows=15905" ?
Regards.
Hiroshi Inoue
Inoue@tpf.co.jp