"Rows" indicates how many rows Oracle expects to get from the table based on predicates/join conditions. It might scan all 53000, but return only 1634 rows to upper operation in execution plan.
Mindaugas
----- Original Message ----
From: "ryan_gaffuri_at_comcast.net" <ryan_gaffuri_at_comcast.net>
To: oracle-l_at_freelists.org
Sent: Tuesday, October 24, 2006 11:21:14 AM
Subject: cardinality/rows column in the explain plan
I am looking at an explain plan with set autotrace on.
Table C has 53,000 rows. When I query dba_tables.num_rows it states that there are 53,000 rows. How can I have 'rows' of 1634 on a full table scan? Shouldn't it be all the rows in the table since Oracle is doing a full table scan?
I get teh same number when I look at the cardinality column in the 'explain plan for'. I had though that Oracle got the rows for a full table scan from dba_tables.num_rows? I guess not.
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Received on Tue Oct 24 2006 - 11:10:09 CDT
