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Materializing the relation
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- To: pgsql-general@xxxxxxxxxxxxxx
- Subject: Materializing the relation
- From: "rupesh bajaj" <rupesh.bajaj@xxxxxxxxx>
- Date: Mon, 11 Jun 2007 20:52:48 +0530
- Cc: shruthi.iisc@xxxxxxxxx
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Hi,
What is the meaning of 'materializing' a relation after sequential scan?
explain select * from tb1, tb2 where tb1.c1 = tb2.c2;
QUERY PLAN
----------------------------------------------------------------
Nested Loop (cost=1.03..2.34 rows=3 width=24)
Join Filter: (tb1.c1 = tb2.c1)
-> Seq Scan on tb2 (cost=0.00..1.04 rows=4 width=12)
-> Materialize (cost=1.03..1.06 rows=3 width=12)
-> Seq Scan on tb1 (cost=
0.00..1.03 rows=3 width=12)
In this above plan, what does 'Material' mean?
Thanks,
Rupesh
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