Re: cardinality/rows column in the explain plan
- From: Mindaugas Navickas <mnavickas@xxxxxxxxx>
- To: ryan_gaffuri@xxxxxxxxxxx, oracle-l@xxxxxxxxxxxxx
- Date: Tue, 24 Oct 2006 09:10:09 -0700 (PDT)
"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@xxxxxxxxxxx" <ryan_gaffuri@xxxxxxxxxxx>
To: oracle-l@xxxxxxxxxxxxx
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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