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SAP NetWeaver Newbie

Enqueue Server Max Requests and Enqueue Table Size

If you start noticing I/O or memory errors in the dev_enqio_* trace file, the enqueue server is being overloaded.

enque/server/max_requests and enque/server/max_query_requests determine the number of requests that can be processed parallely. These numbers should atleast be equal to the number of work processes or the number of Java threads (in all instance).

enque/table_size determines the size of the enqueue table. If there is a memory error in the trace files, increase enque/table_size.

Sample calculations of the max_*request parameters based on number of WPs/threads and enqueue table size:

For ASCS

Total number of WPs = 1000
Lock Table Size = 500MB

enque/server/max_query_requests = 1000
enque/server/max_requests = 1000 + 500 * 25 = 13500. #The additional 25*500 is for handling replication in HA systems.
enque/table_size = 500000

For SCS

Total number of Java Threads per node = 350
Total number of nodes = 3
Lock Table Size = 32MB

enque/server/max_query_requests = 3 * 4 * 350 = 4200
enque/server/max_requests = 4200 + 32 * 25 = 5000
enque/table_size = 32000

5 comments:

  1. I have a question regarding your formula. How did you come up with those factors to multiply with? Currently i am investigating an ENQ problem (semaphore 26). And my gut feeling tells me we should try your formula to determine the right values.

    Kind regards!

    ReplyDelete
    Replies
    1. These are empirical formulas found in an ocean of documentation I got my hands on. An SAP note might be the original source.

      Delete
  2. Note 920979 - Out of memory in standalone enqueue server

    ReplyDelete
  3. Can we change these parameter dynamically using TH_CHANGE_PARAMETER

    ReplyDelete

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