6 Replies Latest reply: Feb 13, 2013 12:27 AM by brunors RSS

    SessMAx is exceeded then RAC fails

    984973
      My RAC cluster seems to have had the load on one node go through the roof and then eventually die.

      This was the first message I received:

      ORA-24418: Cannot open further sessions

      Some syslog messages started coming in after this and then the node in the cluster failed. What would cause the ORA-24418 error?

      Thank you.
        • 1. Re: SessMAx is exceeded then RAC fails
          Sebastian Solbach -Dba Community-Oracle
          Hi,

          probably not enough memory (or in conjunction with memory not enough processes).
          When a node does not have enough memory (due to SGA size + used PGA) the node will start swapping.
          Swapping is really bad as this will result in node reboot (since clusterware processes will not get the resources anymore they need).

          Reduce the memory consumption of the node (by limiting the sessions or using shared server) or increase memory to circumvent this.

          Regards
          Sebastian
          • 2. Re: SessMAx is exceeded then RAC fails
            TSharma-Oracle
            How do I ask a question on the forums?
            SQL and PL/SQL FAQ


            1) What version you are on?
            2) Is Load Balancing on ?
            3) When you get this error , how many session exists on other node?
            4) Check other resources on the box like Memory and CPU?
            • 3. Re: SessMAx is exceeded then RAC fails
              984973
              Hi TSharma,

              What version of what did you want to know?
              • 4. Re: SessMAx is exceeded then RAC fails
                TSharma-Oracle
                Version of Oracle
                • 5. Re: SessMAx is exceeded then RAC fails
                  onedbguru
                  make sure sessions and processes parameters are properly configured and that you have sufficient memory for those settings.
                  • 6. Re: SessMAx is exceeded then RAC fails
                    brunors
                    jackiebaron wrote:
                    My RAC cluster seems to have had the load on one node go through the roof and then eventually die.

                    This was the first message I received:

                    ORA-24418: Cannot open further sessions

                    Some syslog messages started coming in after this and then the node in the cluster failed. What would cause the ORA-24418 error?

                    Thank you.
                    Hello, you will have to do the follow steps:

                    Check the SGA parameters;+
                    Check the Sessions parameters;+
                    Check the version of your Oracle database;+
                    After that, you will analyze de changes for solve the problem. Follow bellow theses steps:

                    oradba> oerr ora 24418
                    24418, 00000, "Cannot open further sessions."
                    // *Cause:  Sufficient number of sessions are not present in the pool to
                    // execute the call. No new sessions can be opened as the
                    // sessMax parameter supplied in OCISessionPoolCreate has been
                    // reached.
                    // *Action: Call OCISessionPoolCreate in OCI_SPOOL_REINITIALIZE mode and
                    // increase the value of the sessMax parameter.

                    oradba@> sqlplus "/as sysdba"

                    SQL*Plus: Release 11.2.0.3.0 Production on Wed Feb 13 04:19:54 2013

                    Copyright (c) 1982, 2011, Oracle. All rights reserved.


                    Connected to:
                    Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
                    With the Partitioning, OLAP, Data Mining and Real Application Testing options

                    SQL> show parameters sga

                    NAME TYPE VALUE
                    ------------------------------------ ----------- ------------------------------
                    lock_sga boolean FALSE
                    pre_page_sga boolean FALSE
                    sga_max_size big integer 45G
                    sga_target big integer 45G
                    SQL> show parameters sess

                    NAME TYPE VALUE
                    ------------------------------------ ----------- ------------------------------
                    java_max_sessionspace_size integer 0
                    java_soft_sessionspace_limit integer 0
                    license_max_sessions integer 0
                    license_sessions_warning integer 0
                    session_cached_cursors integer 50
                    session_max_open_files integer 10
                    sessions integer 2726
                    shared_server_sessions integer
                    SQL> select from v$version;*

                    BANNER
                    --------------------------------------------------------------------------------
                    Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
                    PL/SQL Release 11.2.0.3.0 - Production
                    CORE 11.2.0.3.0 Production

                    Best regards,
                    Bruno Reis.
                    www.brunors.com

                    Edited by: brunors on 13/02/2013 04:26

                    Edited by: brunors on 13/02/2013 04:26

                    Edited by: brunors on 13/02/2013 04:27