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2134996 - Poor performance after recycling ASE - SAP ASE

Symptom

  • After rebooting ASE, there is a significant performance degradation.

  • sp_symon output shows high CPU and I/Os usage, with "I/O Busy" being greater than "CPU Busy". For example:


    Engine Busy Utilization        CPU Busy   I/O Busy       Idle

      ------------------------       --------   --------   --------

        Engine 0                        7.7 %     47.3 %     45.0 %

        Engine 1                       11.1 %     43.4 %     45.4 %

        Engine 2                       12.6 %     45.7 %     41.7 %

        Engine 3                        7.2 %     22.9 %     69.9 %

        Engine 4                       12.9 %     31.1 %     56.0 %

        Engine 5                       10.3 %     19.7 %     69.9 %

        Engine 6                        8.0 %     29.3 %     62.7 %

        Engine 7                        6.8 %     45.5 %     47.6 %

        Engine 8                       12.2 %     44.4 %     43.4 %

        Engine 9                        7.1 %     25.9 %     67.0 %

        Engine 10                      10.6 %     26.6 %     62.8 %

        Engine 11                       9.9 %     52.4 %     37.7 %

        Engine 12                       8.7 %     28.9 %     62.4 %

        Engine 13                       9.8 %     33.2 %     57.0 %

        Engine 14                       6.7 %     24.0 %     69.2 %

        Engine 15                      16.2 %     28.6 %     55.3 %

      ------------------------       --------   --------   --------

      Summary           Total         157.9 %    549.1 %    893.0 %

     

     

    Possible 16K buffer pool issue, high turnover of 16K pool.

     

     

     -------------------------------------------------------------------------------

      Cache: default data cache

                                      per sec      per xact       count  % of total

      -------------------------  ------------  ------------  ----------  ----------

        Spinlock Contention               n/a           n/a         n/a       1.4 %

        Utilization                       n/a           n/a         n/a      95.2 %

     

        Cache Searches

          Cache Hits                 155000.0        1623.5    18621400      99.5 %

             Found in Wash              329.3           3.4       39513       0.2 %

          Cache Misses                  802.7           8.4       96321       0.5 %

      -------------------------  ------------  ------------  ----------

        Total Cache Searches         155981.7        1631.9    18717809

     

        Pool Turnover

          2  Kb Pool

              LRU Buffer Grab           169.8           1.8       20381       5.0 %

                Grabbed Dirty             0.0           0.0           0       0.0 %

          16 Kb Pool

              LRU Buffer Grab          2706.8          28.3      324821      95.0 %

                Grabbed Dirty             0.0           0.0           0       0.0 %

      -------------------------  ------------  ------------  ----------

        Total Cache Turnover           2876.7          30.1      345202


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Environment

Any version of SAP Adaptive Server Enterprise (ASE).

Product

SAP Adaptive Server Enterprise 12.5 ; SAP Adaptive Server Enterprise 15.7 ; SAP Adaptive Server Enterprise 16.0

Keywords

large i/o pool, performance, 16K pool, sizing, i/o performance, cache sizing , KBA , BC-SYB-ASE , Sybase ASE Database Platform (non Business Suite) , BC-DB-SYB , SAP Business Suite on Sybase ASE Database Platform , How To

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