RE: direct path read/write temp waits

Mark,

I am seeing this:

      505 sorts (disk)
0

       505 sorts (rows)
0

       505 sorts (memory)
0

       515 sorts (disk)
0

       515 sorts (rows)
0

       515 sorts (memory)
0

       519 sorts (rows)
0

       519 sorts (disk)
0

       519 sorts (memory)
0

       545 sorts (disk)
0

       545 sorts (memory)
0

       545 sorts (rows)
0

       576 sorts (disk)
0

       576 sorts (rows)
0

       576 sorts (memory)
0

       580 sorts (rows)
0

       580 sorts (memory)
0

       580 sorts (disk)
0

       642 sorts (memory)
1

       642 sorts (disk)
1

       642 sorts (rows)
1269

       655 sorts (rows)
0

       655 sorts (disk)
0

       655 sorts (memory)
0

       668 sorts (rows)
80243

       668 sorts (disk)
3

       668 sorts (memory)
37

       679 sorts (memory)
1

       679 sorts (disk)
1

       679 sorts (rows)
1270

       745 sorts (rows)
0

       745 sorts (memory)
0

       745 sorts (disk)
0

The two sids with the highest number of sorts though (688 and 642) are some other sessions.

thank you

Gene Gurevich
Oracle MySQL Operations - OMO
224-405-4079

                                                                           
             "Bobak, Mark"                                                 
             <Mark.Bobak_at_il.pr                                             
             oquest.com>                                                To 
             Sent by:                  <genegurevich_at_discoverfinancial.com 
             oracle-l-bounce_at_f         >, <oracle-l_at_freelists.org>         
             reelists.org                                               cc 
                                                                           
                                                                   Subject 
             04/25/2007 01:13          RE: direct path read/write temp     
             PM                        waits                               
                                                                           
                                                                           
             Please respond to                                             
             Mark.Bobak_at_il.pro                                             
                 quest.com                                                 
                                                                           
                                                                           

Yeah, the 301 and 302 datafile ids means that you have db_files set to 300. Tempfiles start numbering w/ db_files+1.

As to the sort analysis, what do you get if you do:  select vsn.name, vss.value
   from v$sesstat vss,

        v$statname vsn

  where vsn.name like '%sort%'
    and vss.statistic# = vsn.statistic#
    and vss.sid in(select vs.sid
                     from v$session vs,
                          v$sort_usage vsu
                   where vs.saddr=vsu.session_addr);

-Mark

--

Mark J. Bobak
Senior Oracle Architect
ProQuest/CSA

"There are 10 types of people in the world: Those who understand binary, and those who don't."

-----Original Message-----

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of genegurevich_at_discoverfinancial.com
Sent: Wednesday, April 25, 2007 1:08 PM
To: oracle-l_at_freelists.org
Subject: direct path read/write temp waits

Hi all

I'm trying to find out a way to deal with direct path read/write temp waits. I am loading a table as a select from another table

insert /*+ append */ into table1 (select col1, col2, sum ... from table2 group by ...);

While this is running I see a number of the direct path read/write temp waits in the v$session_waits table I have found a document dealing with this waits on metalink
(http://download-east.oracle.com/docs/cd/B14117_01/server.101/b10752/ins tance_tune.htm)
The file_id that I am seeing are 301 and 302. I only have 55 datafiles in this database so this is definitely a TEMP tablespace. If I read that document correctly, this means that the sorts are too large to fit in memory and some data are written to disk. I have however checked the sessstat table for the sessions listed in the tempseg_usage view and found no data for sorts. I am not sure how to reconcile these two pieces of data.

I am also doing a full scan of one partition in the table2. Both tables are parallelized. My oracle version is 10.2.0.3

thanks for any suggestion

Gene Gurevich

--

http://www.freelists.org/webpage/oracle-l

--

http://www.freelists.org/webpage/oracle-l

--

http://www.freelists.org/webpage/oracle-l Received on Thu Apr 26 2007 - 12:46:30 CDT