Skip to Main Content

Oracle Database Discussions

Announcement

For appeals, questions and feedback about Oracle Forums, please email oracle-forums-moderators_us@oracle.com. Technical questions should be asked in the appropriate category. Thank you!

A lot of messages "direct path write temp" and "direct path read temp"

user12103911Aug 10 2012 — edited Aug 16 2012
Hello, all

Please, understand me, what is going on in my system (DB: Oracle database 11.2.0.3, OS: Windows 2008 R2).

In AWR report (1 hour) I see next:
Foreground Wait Events
                                                             Avg                
                                        %Time Total Wait    wait    Waits   % DB
Event                             Waits -outs   Time (s)    (ms)     /txn   time
-------------------------- ------------ ----- ---------- ------- -------- ------
direct path write temp          132,627     0      1,056       8      0.8   21.7
direct path read temp           308,969     0        565       2      2.0   11.6
log file sync                    19,228     0        241      13      0.1    5.0
direct path write                17,698     0        135       8      0.1    2.8
db file sequential read          21,149     0         94       4      0.1    1.9
SQL*Net message from dblin           59     0          5      86      0.0     .1
...
Segments by Direct Physical Reads         DB/Inst: SGRE/sgre  Snaps: 1039-1040
-> Total Direct Physical Reads:         392,273
-> Captured Segments account for   94.7% of Total

           Tablespace                      Subobject  Obj.        Direct        
Owner         Name    Object Name            Name     Type         Reads  %Total
---------- ---------- -------------------- ---------- ----- ------------ -------
** MISSING TEMP       ** TRANSIENT: 437734 MISSING ** UNDEF       38,290    9.76
DBSNMP     TEMP       MGMT_TEMPT_SQL                  TABLE       38,242    9.75
** MISSING TEMP       ** TRANSIENT: 438784 MISSING ** UNDEF       37,790    9.63
** MISSING TEMP       ** TRANSIENT: 437312 MISSING ** UNDEF       37,661    9.60
** MISSING TEMP       ** TRANSIENT: 439257 MISSING ** UNDEF       37,477    9.55
Some selects:
SELECT   S.sid,
         T.blocks * TBS.block_size / 1024 / 1024 mb_used, T.tablespace, T.SEGTYPE
FROM     v$sort_usage T, v$session S, v$sqlarea Q, dba_tablespaces TBS
WHERE    T.session_addr = S.saddr
AND      T.sqladdr = Q.address (+)
AND      T.tablespace = TBS.tablespace_name
AND      S.sid = 732
ORDER BY S.username, S.sid;

SID	MB_USED	TABLESPACE	SEGTYPE
732	2		TEMP		LOB_DATA
732	1		TEMP		INDEX
732	1		TEMP		DATA
732	1		TEMP		INDEX
732	1		TEMP		DATA
732	1		TEMP		INDEX
732	1		TEMP		DATA
732	1		TEMP		INDEX
732	1		TEMP		INDEX
732	1		TEMP		DATA
732	1		TEMP		INDEX
732	1		TEMP		INDEX
732	1		TEMP		DATA
732	1		TEMP		INDEX
732	1		TEMP		INDEX
732	1		TEMP		DATA
732	1		TEMP		INDEX
732	1		TEMP		INDEX
732	1		TEMP		DATA
732	1		TEMP		INDEX
732	1		TEMP		INDEX
732	1		TEMP		DATA
732	1		TEMP		INDEX
732	1		TEMP		INDEX
732	1		TEMP		DATA
732	1		TEMP		INDEX
732	1		TEMP		INDEX
732	1		TEMP		DATA
732	1		TEMP		INDEX
732	1		TEMP		LOB_INDEX
select st.sid, sn.name, st.VALUE
from V$statname sn, v$sesstat st
where st.STATISTIC# = sn.STATISTIC#
and (sn.name like 'sorts%')
and st.sid in (select sid from v$session_wait where event like '%direct path write temp%')
order by st.sid

SID	NAME		VALUE
732	sorts (memory)	591408
732	sorts (rows)	102126
732	sorts (disk)	0
Why I do not see any disk sorts? If TEMP is used for no sort operations, then for which operations?
How I can see that? How can I decrease direct path write temp without tuning SQL?

Additional information:
PGA_AGGREGATE_TARGET is set to big value - 6GB (3GB enough due to advisory recommendation)

Please, help.

Regards, user12103911.
Comments
Locked Post
New comments cannot be posted to this locked post.
Post Details
Locked on Sep 13 2012
Added on Aug 10 2012
21 comments
6,657 views