IT27475: RTO_SERVER_RESTART DOES NOT TRIGGER CHECKPOINTS AS SHOULD TO KEEP THE ESTIMATED RECOVERY TIME CLOSE TO THE SET

APAR status

• Closed as program error.

Error description

• According to documentation checkpoints should have been
  triggered by RTO to try to accomplish the setting and it shows ~
  9 times the expected during ~ 20 hours and no action.
  
  IBM Informix Dynamic Server Version 12.10.FC9X1 -- On-Line -- Up
  26 days 21:31:34 -- 168610192 Kbytes
  
  AUTO_CKPTS=On   RTO_SERVER_RESTART=120 seconds   Estimated
  recovery time 1171 seconds
  
  
  Critical Sections                          Physical Log
  Logical Log
             Clock                                  Total Flush
  Block #      Ckpt  Wait  Long  # Dirty   Dskflu  Total    Avg
  Total    Avg
  Interval   Time      Trigger    LSN               Time  Time
  Time  Waits  Time  Time  Time  Buffers   /Sec    Pages    /Sec
  Pages    /Sec
  4490       11:47:53 *Backup     141512:0x25afd58  161.8 161.0
  0.0   9      0.1   161.9 161.9 1061848   6597    644340   105
  575458   94
  4491       16:09:13  Plog       141601:0x14c1590  264.5 249.3
  0.0   19     0.0   0.9   1.1   1255739   5038    1168631  75
  1379244  88
  4492       16:09:27 *User       141602:0x21273c4  14.2  10.7
  0.0   23     0.0   14.0  14.2  65677     6164    83386    315
  18534    70
  4493       16:09:45 *User       141602:0x261b06c  8.3   2.6
  0.0   19     0.0   8.4   8.4   7360      2831    7260     330
  1268     57
  4494       16:11:16 *User       141604:0x1f892b8  0.9   0.7
  0.0   16     0.0   0.9   0.9   7067      7067    35447    358
  8100     81
  4495       16:13:13 *User       141605:0x28772a0  0.3   0.2
  0.0   6      0.0   0.3   0.3   2540      2540    39223    332
  10718    90
  4496       16:15:16 *User       141607:0x270d7a8  1.2   1.1
  0.0   8      0.0   1.2   1.2   2665      2429    51661    423
  25430    208
  4497       16:17:17 *User       141608:0x2256908  1.1   0.7
  0.0   15     0.0   1.1   1.1   22812     22812   33729    278
  8905     73
  4498       16:20:20 *User       141611:0x1ddc4f4  0.4   0.2
  0.0   11     0.0   0.3   0.4   4704      4704    75148    410
  38450    210
  4499       16:21:11 *User       141612:0xf225f4   0.4   0.3
  0.0   6      0.0   0.4   0.4   1308      1308    19617    377
  3952     76
  4500       16:23:12 *User       141613:0x285aa2c  0.3   0.2
  0.0   5      0.0   0.3   0.3   2877      2877    44845    370
  10415    86
  4501       21:47:59  Plog       141738:0x2e320cc  194.3 193.9
  0.0   10     0.0   0.0   0.0   1243736   6414    1176608  60
  1932285  100
  4502       21:48:04 *Backup     141739:0x2f591d0  5.1   3.5
  0.0   23     0.0   4.6   5.1   51332     14664   46914    240
  15655    80
  4503       00:36:20  Plog       141817:0x3ae71d4  222.7 218.1
  0.0   18     0.0   0.6   0.7   1293763   5930    1107517  112
  1212327  122
  4504       02:12:30  Plog       141900:0x334db50  301.1 284.4
  0.0   377    0.2   0.1   0.2   1381618   4858    971653   170
  1310955  230
  4505       02:55:01  Plog       141926:0x9b74bc   206.6 206.2
  0.0   130    0.0   0.1   0.1   1207591   5857    1234265  466
  404569   152
  4506       03:25:20  Plog       141948:0x2ba1c18  144.3 144.0
  0.0   81     0.0   0.0   0.0   1283052   8912    1125546  598
  356510   189
  4507       04:02:35  Plog       141966:0x1f87b6c  145.5 145.1
  0.0   27     0.0   0.0   0.0   1208028   8323    1243186  556
  285963   128
  4508       06:23:12  Plog       142018:0x244fa98  249.9 249.3
  0.0   8      0.0   0.0   0.0   1262495   5064    1155555  138
  816029   97
  4509       08:42:12  Plog       142058:0x36c7e6c  185.9 184.2
  0.0   13     0.0   0.0   0.0   1571175   8530    685085   81
  636503   75
  
  Max Plog       Max Llog       Max Dskflush   Avg Dskflush   Avg
  Dirty      Blocked
  pages/sec      pages/sec      Time           pages/sec
  pages/sec      Time
  9802           3362           399            6362           93
  0
  
  The physical log size is smaller than the recommended size for a
  server
  configured with RTO_SERVER_RESTART.  Fast recovery performance
  might not
  be optimal. For best fast recovery performance when
  RTO_SERVER_RESTART
  is enabled, increase the physical log size to at least 167360758
  KB.
  For servers configured with a large buffer pool, this might
  not be necessary. See the Administrator's Guide for more
  information.
  Based on the current workload, the physical log might be too
  small
  to accommodate the time it takes to flush the buffer pool during
  checkpoint processing.  The server might block transactions
  during checkpoints.
  If the server blocks transactions, increase the physical log
  size to
  at least 17016272 KB.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of Informix Server prior to 12.10.xC11.                *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * RTO_SERVER_RESTART DOES NOT TRIGGER CHECKPOINTS AS SHOULD TO *
  * KEEP THE ESTIMATED RECOVERY TIME CLOSE TO THE SET            *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Informix Server 12.10.xC11+.                      *
  ****************************************************************
  

Problem conclusion

• Problem fixed in Informix Server 12.10.xC11+.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  INFORMIX SERVER

• Fixed component ID

  5725A3900

Applicable component levels