Re: Empty Table
- From: "jaromir nemec" <jaromir@xxxxxxxxxxxx>
- To: <jkstill@xxxxxxxxx>
- Date: Tue, 25 Jan 2005 02:09:58 +0100
Hi Jared,
yes, with hint suppressing parallelism everything is OK. The feature deploy
only if you leverage both power features PX and partitioning:) See below.
Regards
Jaromir
Connected to:
Oracle Database 10g Enterprise Edition Release 10.1.0.2.0 - Production
With the Partitioning, OLAP and Data Mining options
SQL> set autotrace on
SQL> select count(*) from TEST where rownum = 1;
COUNT(*)
----------
1
Execution Plan
----------------------------------------------------------
0 SELECT STATEMENT Optimizer=ALL_ROWS (Cost=21562 Card=1)
1 0 SORT (AGGREGATE)
2 1 COUNT (STOPKEY)
3 2 PX COORDINATOR
4 3 PX SEND* (QC (RANDOM)) OF ':TQ10000' (Cost=21562 Car
:Q1000
d=7639515)
5 4 PX BLOCK* (ITERATOR) (Cost=21562 Card=7639515)
:Q1000
6 5 TABLE ACCESS* (FULL) OF 'TEST' (TABLE) (Cost=215
:Q1000
62 Card=7639515)
4 PARALLEL_TO_SERIAL
5 PARALLEL_COMBINED_WITH_CHILD
6 PARALLEL_COMBINED_WITH_PARENT
Statistics
----------------------------------------------------------
31 recursive calls
3 db block gets
100640 consistent gets
100267 physical reads
660 redo size
393 bytes sent via SQL*Net to client
512 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
5 sorts (memory)
0 sorts (disk)
1 rows processed
SQL>
SQL> select /*+ parallel(t,1) */ count(*) from TEST t where rownum = 1;
COUNT(*)
----------
1
Execution Plan
----------------------------------------------------------
0 SELECT STATEMENT Optimizer=ALL_ROWS (Cost=40145 Card=1)
1 0 SORT (AGGREGATE)
2 1 COUNT (STOPKEY)
3 2 PARTITION RANGE (ALL) (Cost=40145 Card=7639515)
4 3 TABLE ACCESS (FULL) OF 'TEST' (TABLE) (Cost=40145 Ca
rd=7639515)
Statistics
----------------------------------------------------------
1 recursive calls
0 db block gets
4 consistent gets
5 physical reads
0 redo size
393 bytes sent via SQL*Net to client
512 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed
SQL>
----- Original Message -----
From: "Jared Still" <jkstill@xxxxxxxxx>
To: "jaromir nemec" <jaromir@xxxxxxxxxxxx>
Cc: <andert@xxxxxxxxx>; <jacintakean@xxxxxxxxx>; <oracle-l@xxxxxxxxxxxxx>
Sent: Tuesday, January 25, 2005 12:05 AM
Subject: Re: Empty Table
Interesting. I hadn't considered that.
So, did you try your query with a NOPARALLEL hint?
Jared
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