High CPU Usage of DB2 Process after Upgrade to RTC 4.0.4
Were running RTC 4.0.4 with DB2 10.1 Express-C on RHEL 6.
The server is configured with 4 cores and 8GB RAM.
After the upgrade from 4.0.3 to 4.0.4 we see the db2sysc processs running at nearly 200%.
Linux top-command says:
Prior to 4.0.4 it used only very little cpu.
However, the machine and RTC runs very smooth, no user complaints, we only discovered this issue through our monitoring tool.
Any suggestions on how to solve this?
Thanks,
Daniel
The server is configured with 4 cores and 8GB RAM.
After the upgrade from 4.0.3 to 4.0.4 we see the db2sysc processs running at nearly 200%.
Linux top-command says:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2234 db2inst1 20 0 7540m 890m 581m S 199.9 11.3 127028:57 db2sysc
Prior to 4.0.4 it used only very little cpu.
However, the machine and RTC runs very smooth, no user complaints, we only discovered this issue through our monitoring tool.
Any suggestions on how to solve this?
Thanks,
Daniel
One answer
Ok,
with db2top I found only low activity, but there are some locks on the CCM-Database:
Locks held.......: 7 [0,00%]
Agents waiting...: 0
Appls Connected..: 5
Agent Application Application
Id(State) Name Status
------------ -------------------- -----------------------------------
25479(*) DSSNAP_logMessage UOW Executing
25479(*) DSSNAP_logMessage UOW Executing
25470(c) db2evmt_JAZZ_DEADLOC Connected
25470(c) db2evmt_JAZZ_DEADLOC Connected
25470(c) db2evmt_JAZZ_DEADLOC Connected
25470(c) db2evmt_JAZZ_DEADLOC Connected
25470(c) db2evmt_JAZZ_DEADLOC Connected
Is this normal behavior?
with db2top I found only low activity, but there are some locks on the CCM-Database:
Locks held.......: 7 [0,00%]
Agents waiting...: 0
Appls Connected..: 5
Agent Application Application
Id(State) Name Status
------------ -------------------- -----------------------------------
25479(*) DSSNAP_logMessage UOW Executing
25479(*) DSSNAP_logMessage UOW Executing
25470(c) db2evmt_JAZZ_DEADLOC Connected
25470(c) db2evmt_JAZZ_DEADLOC Connected
25470(c) db2evmt_JAZZ_DEADLOC Connected
25470(c) db2evmt_JAZZ_DEADLOC Connected
25470(c) db2evmt_JAZZ_DEADLOC Connected
Is this normal behavior?
Comments
Daniel,
I've seen the JAZZ_DEADLOC(K). The DSSNAP I've never seen; but it's probably 'normal'. The thing to watch for there is "Agents waiting" > 0 for long periods of time.
Googled and found:
http://www.dbforums.com/db2/1671392-db2sysc-using-more-than-100-cpu.html
See the comments by "Marcus A"
The chase: you may be getting misled by what you see.
Comments
Kevin Ramer
Nov 21 '13, 2:23 p.m.There are a couple db2 utilities that might shed light on this in addition to what you might see in 'top' or iostat. I like db2top. Run as the instance owner
db2top -d DBNAME
where DBNAME is one of the databases.
This can show session activity, table/tablespace activity, locks, etc. I recommend these pages
You may or may not find the 'smoking gun'.
db2diag lets you query the sqllib/db2dump/db2diag.log in many ways.
nmon this one is like top or aix topas and you can run it in the background and collect lots of stats. There's an nmon analyzer Excel worksheet that can import nmon files and draw nice graphs. pGraph (a java tool) can also read the nmon files in case you're unable to use Excel.
Hope this helps