Reading UNDO and displaying it in v$session

From: Milen Kulev <>
Date: Wed, 02 Apr 2008 12:48:24 +0200
Message-ID: <>

Hello Listers,
I have a following dilemma :
I am quering v$session to get information what each session is waiting for. For a specific session I am getting "direct path write temp" (from v$sesion.EVENT) waits event (generary means sorting in temp tablespace). For the same session I am getting

11:56:26 SQL> select ROW_WAIT_OBJ# , ROW_WAIT_FILE#, ROW_WAIT_BLOCK#, ROW_WAIT_ROW# from v$session where sid = 168 ;

------------- -------------- --------------- -------------

            0 14 201328 0

So, I can NOR resolve the objects accessed at thius moment (ROW_WAIT_OBJ# =0) The file corriesponding to ROW_WAIT_FILE#=14 is a datafile belonging to UNDO tablespace !

 select OWNER, SEGMENT_NAME, TABLESPACE_NAME from dba_extents where FILE_ID=14 and 201328 between BLOCK_ID and block_id + blocks -1 ;

------- -----------------

SYS                            _SYSSMU9$                                                                        ORAUNDO

The questions:
1) How to interptet "direct path write temp" wait event in UNDO tablespace? 2) Is there any information (papers, presentation, links) how to interpret the wait event when v$session.ROW_WAIT_OBJ# <=0 ?

I would appreciate any information about this topic.

Best Regards


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-- Received on Wed Apr 02 2008 - 05:48:24 CDT

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