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Kirit Rana asked what the hex number after pt_ in a mutex name in onstat -g lmx output means, on IDS 11.70.FC7. Art Kagel said it is the partnum of the locked partition and gave the decimal conversion. Paul Watson added that pt_ is the partition mutex; convert the hex to decimal to find the table, and oncheck -pT may help. Kirit confirmed this solved it.
Auto-generated by Claude from the posts below — may be imperfect; read the full thread.
Kirit Rana — source: IBM Community (ConnectedCommunity.org) Informix forum
Consider this excerpt from an
onstat -g lmx
output...Locked mutexes:
mid addr name holder lkcnt waiter waittime
-824449722 10509f7f9b8 pt_40efa1 1592045984 0
Does anybody know what the hex number after the
pt_
in the mutex name relates to? I have not been able to find this detail in any manuals.
I found this on the old IIUG forum site...
"
pt__ are locks on the partition. Normally that means that threads are expanding a tablespace.
"
...but I want to be able to identify the object that is at the root of the mutex contention. My understanding is that mutex lock contention happens when session threads are trying to initialise the same structure in memory that is already being referenced by another session and thus are put to sleep.
Any assistance would be appreciated.
Platform...
Linux ******* 2.6.32-754.17.1.el6.x86_64 #1 SMP Thu Jun 20 11:47:12 EDT 2019 x86_64 x86_64 x86_64 GNU/Linux
IBM Informix Dynamic Server Version 11.70.FC7XOB4 -- On-Line -- Up 219 days 13:12:30 -- 799279104 Kbytes
------------------------------Kirit Rana
------------------------------
#Informix
↪ replying to Kirit Rana
Art Kagel — source: IBM Community (ConnectedCommunity.org) Informix forum
Kirit:
It should be the partnum of the partition being locked. Converting the hex to decimal yields partnum =
4255649.
Art
------------------------------
Art S. Kagel, President and Principal Consultant
ASK Database Management Corp.
www.askdbmgt.com
------------------------------
↪ replying to Kirit Rana
Paul Watson — source: IBM Community (ConnectedCommunity.org) Informix forum
Pt_* is the partition mutex, lots of them are not documented as the full name is dynamic. However most are <2char>_<number>. You can normally guess from the 2 char
Convert the numeric part from to hex to decimal and use that to find the table. You might get lucky and oncheck –pT will work
Cheers
Paul
↪ replying to Paul Watson
Kirit Rana — source: IBM Community (ConnectedCommunity.org) Informix forum
Excellent. Got it. Now I can identify the table or index I suspect is the root of the contention and take the investigation further.
Thanks Paul and Art.
------------------------------
Kirit Rana
------------------------------
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