RE: Reading UNDO and displaying it in v$session

Hello Brandon,
yes, I am aware of this fact , but my goal was (and is) to write a performance monitoring skript that provides me with the infomation
about sessions details (SID, SPID, WAIT EVENT , Session State, SQL_ID, CHILD_NR tomention a few) and object_id of the the database object beining accesed at the moment. The link below describes actually (this is my understanding, at least) the dependency of ROW_WAIT_ROW# on ROW_WAIT_OBJ#.
Perhaps ROW_WAIT_ROW# is interesting (in combination witn ROW_WAIT_OBJ# and the other ROW_WAIT_*# from V$session) when EVENT='enq: TX - row lock contention' ?  

Best Regards. Milen    

-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Allen, Brandon Sent: Thursday, April 03, 2008 6:33 PM
To: makulev_at_gmx.net; kylelf_at_gmail.com; oracle-l_at_freelists.org Subject: RE: Reading UNDO and displaying it in v$session

Hi Milen,

I believe the purpose of row_wait_obj#, and the other row_wait columns is only to report relevant information when a session is waiting on a blocking lock, i.e. the "enqueue" wait event for a TX (aka Transaction) lock. Here are the column descriptions from the documentation:

 <http://stanford.edu/dept/itss/docs/oracle/10g/server.101/b10755/dynviews_2073.htm> http://stanford.edu/dept/itss/docs/oracle/10g/server.101/b10755/dynviews_2073.htm

Please note the following:

ROW_WAIT_ROW# - Current row being locked. This column is valid only if the session is currently waiting for another transaction to commit and the value of ROW_WAIT_OBJ# is not -1. (emphasis mine)

Regards,
Brandon  

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