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CURRENT_OBJ# -1 in v$active_session_history [message #573807] Thu, 03 January 2013 05:09 Go to next message
tom_watson
Messages: 8
Registered: January 2013
Junior Member
Hi,

I am currently querying v$active_session_history as I want to get a wait count for "db file sequential read" waits per object. However, when I run the query below, the largest number of waits are for CURRENT_OBJ# equal to "-1". Does anyone know what object this refers to (querying dba_objects for -1 returns no rows) and I haven't had any luck googling..

Query
select current_obj#, count(*) cnt
from v$active_session_history
where event = 'db file sequential read'
group by current_obj#

Thanks,
Tom.
Re: CURRENT_OBJ# -1 in v$active_session_history [message #573810 is a reply to message #573807] Thu, 03 January 2013 05:17 Go to previous messageGo to next message
Michel Cadot
Messages: 58860
Registered: March 2007
Location: Nanterre, France, http://...
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Account Moderator
Quote:
the largest number of waits are for CURRENT_OBJ# equal to "-1".


This means the session is not currently waiting.
You have to check SESSION_STATE to see if the session is waiting.

Regards
Michel
Re: CURRENT_OBJ# -1 in v$active_session_history [message #573815 is a reply to message #573810] Thu, 03 January 2013 05:47 Go to previous messageGo to next message
tom_watson
Messages: 8
Registered: January 2013
Junior Member
Hi Michel,

I have specified "and session_state = 'WAITING'" in my query now (below) but am seeing the same result:

Query
select current_obj#, count(*) cnt
from v$active_session_history
where event = 'db file sequential read'
and session_state = 'WAITING'group by current_obj#

Thanks,
Tom.
Re: CURRENT_OBJ# -1 in v$active_session_history [message #573819 is a reply to message #573815] Thu, 03 January 2013 06:20 Go to previous messageGo to next message
Michel Cadot
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Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
You also have to exclude background processes: session_type='FOREGROUND'.

Regards
Michel
Re: CURRENT_OBJ# -1 in v$active_session_history [message #573822 is a reply to message #573819] Thu, 03 January 2013 06:31 Go to previous messageGo to next message
tom_watson
Messages: 8
Registered: January 2013
Junior Member
Hi Michel,

When I run

select current_obj#, count(*) cnt
from v$active_session_history
where event = 'db file sequential read'
and session_state = 'WAITING'
and session_type = 'FOREGROUND'
group by current_obj#


I am still getting counts for CURRENT_OBJ# with a value of -1.

Thanks,
Tom.

[Updated on: Thu, 03 January 2013 06:33]

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Re: CURRENT_OBJ# -1 in v$active_session_history [message #573823 is a reply to message #573822] Thu, 03 January 2013 06:38 Go to previous messageGo to next message
Michel Cadot
Messages: 58860
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
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What are these sessions?

Regards
Michel
Re: CURRENT_OBJ# -1 in v$active_session_history [message #573833 is a reply to message #573823] Thu, 03 January 2013 07:52 Go to previous messageGo to next message
tom_watson
Messages: 8
Registered: January 2013
Junior Member
They are a mix of sessions, some selects, some inserts, across different programs including SQL*Plus....

[Updated on: Thu, 03 January 2013 08:01]

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Re: CURRENT_OBJ# -1 in v$active_session_history [message #573906 is a reply to message #573833] Fri, 04 January 2013 03:01 Go to previous messageGo to next message
tom_watson
Messages: 8
Registered: January 2013
Junior Member
Hi Michel,

Just so you know, I raised an SR for this and it's actually a bug on AIX (13843927). What's more...it's an "unfeasible to fix bug".

Thanks,
Tom.
Re: CURRENT_OBJ# -1 in v$active_session_history [message #573925 is a reply to message #573906] Fri, 04 January 2013 05:41 Go to previous message
Michel Cadot
Messages: 58860
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
Thanks for the feedback, I was clueless, this will help.

Regards
Michel
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