Maximo Open Forum

Expand all | Collapse all

Maximo database connection pool

  • 1.  Maximo database connection pool

    Posted 02-28-2021 05:58
    Dear All, 

      We are in a situation where the database connection are not getting closed. It remains in v$session table. Our DBA is claiming because it remains inactive and consume memory the performance of the application gradually slow. We need to either kill the session or restart the server.
    As per my understanding Maximo uses it's own db pooling. It doesn't use application server pool. The session are greeting back to pool once the process complete or after garbage collection. 

    So please help me to understand the pool concept in Maximo. Is it normal to see high  no of connection in v$session table. For example for 200 concurrent user's we can see around 600 connections.

    I would love to hear from the experts here. 

    Thanks 
    Alok
    #Administration

    ------------------------------
    Alok Pattnaik
    Praxis Solutions
    ------------------------------


  • 2.  RE: Maximo database connection pool

    Maximo Certified
    Posted 03-04-2021 00:05
    Hi Alok,

    I have seen this issue with Oracle 11g way back with Maximo 6 and 7.1. This a known problem that Maximo environment with Oracle.
    Maximo has its own connection pooling and it clears the session from MAXSESSION table but can't clear them from V$SESSION table which is managed by Oracle. There are a set of properties related to connection pooling which you can find in System Properties application - 



    This is what I also got a response from IBM over discussion related to the explanation of this issue - https://www.ibm.com/support/pages/why-are-my-oracle-sessions-inactive

    You should revisit automation scripts if any available, or reports to ensure that you are not leaving DB connection open.  Also, check the oracle parameters on DB is set per best practices guidelines from IBM. These parameters impact Maximo performance and Oracle session management - 

    CURSOR_SHARING
    FORCE
    NLS_LENGTH_SEMANTICS
    CHAR
    WORKAREA_SIZE_POLICY=AUTO
    PROCESSES=4000
    OPEN_CURSORS=3000
    SESSIONS=4000
    TRANSACTIONS=2425
    SESSION_CACHED_CURSORS=400
    SESSION_MAX_OPEN_FILES=300

    You can read more about connection pooling and tuning - 

    https://www.ibm.com/support/pages/explanation-maximo-application-server-connection-pooling-and-management
    https://www.ibm.com/support/pages/tuning-connection-pool-properties-websphere-application-server

    Hope this helps!

    ------------------------------
    Prashant Sharma
    EAM360
    ------------------------------



  • 3.  RE: Maximo database connection pool

    Posted 03-04-2021 00:17
    Dear Prashant, 

      Many thanks for your time and details explanation. 

    Yes we already set these properties but it seems it is not working as expected. As you said session can't get clear form v$session, it could be the reason.

    Also I will check with our database team about the database parameters. 

    Thanks 
    Alok

    ------------------------------
    Alok Pattnaik
    Praxis Solutions
    ------------------------------



  • 4.  RE: Maximo database connection pool

    Maximo Certified
    Posted 03-04-2021 01:36
    I think opening a PMR with IBM and taking their opinion should also help. These properties are not responsible for clearing sessions so not sure what do you mean by they are not working properly.

    You can talk to DBA  to create a job to clear these sessions and restart db on peridic frequency to solve this issue.

    Thanks
    Prashant


    ------------------------------
    Prashant Sharma
    EAM360
    ------------------------------



  • 5.  RE: Maximo database connection pool

    Posted 03-08-2021 00:21
    Hi Prasant,

      We are still in 7. 5 so not able raise PMR. Currently upgrade going on. I was talking about the property which can be set for closing long run connection. We set these properties but no use.

    Thanks 
    Alok

    ------------------------------
    Alok Pattnaik
    Praxis Solutions
    ------------------------------