Probably because you have a join with no filter. If you don't filter the
results, I'd think the optimizer would lean heavily towards FTS, since
you're bringing back all of the rows anyway. Based on statistics, the
optimizer will determine which table or tables to FTS.
My $.02
Rich
Rich Jesse System/Database Administrator
[EMAIL PROTECTED] Quad/Tech International, Sussex, WI USA
-----Original Message-----
Sent: Tuesday, March 25, 2003 2:24 PM
To: Multiple recipients of list ORACLE-L
Hi:
We have an oracle 8173 running on Solaris 2.8. I am trying to understand why
oracle chooses the Full Table scan in it's explain plan in the floowing
query:
SQL> SET AUTOTRACE TRACEONLY EXPLAIN;
SQL> select TermID from Observationlist, TermObs where ID = ObsID;
Execution Plan
----------------------------------------------------------
0 SELECT STATEMENT Optimizer=CHOOSE (Cost=9477 Card=2633337 By
tes=44766729)
1 0 HASH JOIN (Cost=9477 Card=2633337 Bytes=44766729)
2 1 INDEX (FAST FULL SCAN) OF 'PK_OBSERVATION' (UNIQUE) (Cos
t=834 Card=2513357 Bytes=15080142)
3 1 TABLE ACCESS (FULL) OF 'TERMOBS' (Cost=1126 Card=2633337
Bytes=28966707)
[snip]
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Author: Jesse, Rich
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