| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
 |
 | |||
| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
|
| |||
Home -> Community -> Mailing Lists -> Oracle-L -> RE: DUAL revisited
Just wondering here but has anyone tried doing that select from something
like v$database;
Statistics
0 recursive calls
0 db block gets
0 consistent gets
0 physical reads
0 redo size
187 bytes sent via SQL*Net to client
248 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed
that looks pretty good to me!!
-----Original Message-----
Sent: Friday, August 02, 2002 11:13 AM
To: Multiple recipients of list ORACLE-L
I've been reading the thread on DUAL vs X$DUAL, read the referenced article and tried some testing on our system. I do a simple select from DUAL and I get the same statistics as were in the article, but sometimes I also get 1 memory sort. Does anyone know why this would be? And if this is true, that really makes me want to change over to X$DUAL. Also, what is the consensus about creating a view for DUAL that references X$DUAL? I'm running the Oracle Application and cannot change all of their code to use something other than DUAL, and there is a lot of it.
Here are the statistics on the select. Notice the difference between the first vs repeat of the same seelct.
Connected to:
Oracle8i Enterprise Edition Release 8.1.7.1.1 - Production
With the Partitioning option
JServer Release 8.1.7.1.1 - Production
SQL> set autotrace traceonly
SQL> select 'y' from dual;
Execution Plan
0 SELECT STATEMENT Optimizer=CHOOSE (Cost=2 Card=1) 1 0 TABLE ACCESS (FULL) OF 'DUAL' (Cost=2 Card=1)
Statistics
0 recursive calls
4 db block gets
1 consistent gets
0 physical reads
0 redo size
361 bytes sent via SQL*Net to client
425 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
1 rows processed
0 SELECT STATEMENT Optimizer=CHOOSE (Cost=2 Card=1) 1 0 TABLE ACCESS (FULL) OF 'DUAL' (Cost=2 Card=1)
Statistics
0 recursive calls
4 db block gets
1 consistent gets
0 physical reads
0 redo size
361 bytes sent via SQL*Net to client
425 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed
John Zoltak
North American Mfg Co
4455 East 71st Street
Cleveland Ohio 44105
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: John Zoltak INET: JohnZoltak_at_namfg.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing ListsReceived on Fri Aug 02 2002 - 12:49:19 CDT
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: david hill INET: david.hill_at_lechateau.ca Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
 |
 |