unsch_req in Sybase 16

[Former Member]

Hi, what todo when the the databaseserver (Sybase 16 EBF 2344) is using up to 100 % of 2CPU with total of 32cores

multiprogramming-level is off and at 96 (calculating 3*32 cores)

i wachted into the performance counter for unscheduled request. They are frequently over 5 somtimes over 15 (for 2-3 Seconds) So i think the databaseserver is permanently busy...

• Do you think there is a context between the unsheduled requests and the heavy workload of the CPU?
• What can i do to reduce the unscheduled requests/CPU-Workload?

[Vlad]

... and what was the solution / root cause?

[Breck_Carter]

When the server-level UnschReq property is high (e.g., 5), what are the values of these other properties?

server-level ActiveReq

connection-level ReqStatus; e.g., how many are Executing, Idle, Unscheduled, BlockedIO, BlockedContention, BlockedLock

Also have a look at how fast the connection-level ApproximateCPUTime is increasing... there may be a runaway connection stealing all the cycles.

If you jack up MultiProgrammingLevel to, for example, 200 and the UnschReq remains high, then it may be some kind of contention among connections.

CALL sa_server_option ( 'AutoMultiProgrammingLevel',    'NO' );
CALL sa_server_option ( 'MaxMultiProgrammingLevel',     '200' );
CALL sa_server_option ( 'CurrentMultiProgrammingLevel', '200' ); 

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IMO, however, Foxhound will save you a lot of time 🙂

See the White Paper here.

[Former Member]

i always see nice screenshots of foxhound but have some toubles to setup it. So I continued to use the system functions, no so clear and easy but i'll give foxhound a new try.

[VolkerBarth]

I'm sure Breck is willing and able to help to setup his product:)