IT32257: SQLEXEC THREAD CAN GET STUCK SPINNING INDEFINITELY IN PFSC_ADD_OR_UPD() WHILE IN CRITICAL SECTION AND BLOCK CHECKPOINTS

APAR status

• Closed as program error.

Error description

• When the problem occurs, you will often see messages like the
  following in the online.log:
  
  03/21/20 23:08:21  INC REFCOUNT: invalid refcount 55 entry
  0x7000000502d08a0
  03/21/20 23:08:21  DEC REFCOUNT: invalid refcount 56 entry
  0x7000000502d08a0
  03/21/20 23:08:21  pfsc_del_numidx: pfsc 0x502ce028 page 19544
  unexpected ref. count 55
  03/21/20 23:08:21  pfsc_add_or_upd: partn 0x200043 failed to
  remove page 19544 from pg index
  03/21/20 23:08:21  INC REFCOUNT: invalid refcount 55 entry
  0x7000000502d08a0
  03/21/20 23:08:21  pfsc_add_or_upd: partnum 0x200043 existing
  entry found for page no. 18904
  03/21/20 23:08:21  INC REFCOUNT: invalid refcount 56 entry
  0x7000000502d08a0
  03/21/20 23:08:21  DEC REFCOUNT: invalid refcount 57 entry
  0x7000000502d08a0
  03/21/20 23:08:21  pfsc_del_numidx: pfsc 0x502ce028 page 18904
  unexpected ref. count 56
  
  After these messages appear, the running thread will have a
  stack like:
  
  $ procstack 8847648
  8847648: oninit -ivy
  0x000000010089e480  pfsc_add_or_upd() + 0x280
  0x00000001008a1e90  update_pfsc@AF58_20() + 0x50
  0x0000000100c1ee34  delrecord() + 0x1294
  0x0000000100c1db04  rsdelrec() + 0x1e4
  0x0000000100c16a84  isdelrec() + 0x24
  0x00000001008f533c  fmdelrec() + 0x13c
  0x000000010050dc2c  sqisdelrec() + 0x2c
  0x00000001009fe410  aud_sqisdelrec() + 0x50
  0x000000010104d4bc  dodelete() + 0x45c
  0x000000010104b404  chkrowcons() + 0x1524
  0x00000001010540cc  dodmlrow() + 0x82c
  0x0000000101056c38  dodelupd() + 0xa58
  0x0000000100a0614c  aud_dodelupd() + 0xc
  0x00000001009e7db0  excommand() + 0x1030
  0x00000001006cfc84  sq_execute_workhorse() + 0x1e4
  0x00000001006d04ec  sq_execute() + 0x6c
  0x0000000100760b88  sqmain() + 0x1c8
  0x0000000100b52590  listen_verify() + 0x4d0
  0x0000000100b50f64  spawn_thread() + 0x1044
  0x0000000100b4c99c  th_init_initgls() + 0x5c
  0x0000000101a1139c  startup() + 0x1bc
  
  And an onstat -u will show the thread in critical section and
  the onstat banner can show CKPT REQ:
  
  IBM Informix Dynamic Server Version 14.10.FC3 -- On-Line (CKPT
  REQ) -- Up 00:37:06 -- 273264 Kbytes
  Blocked:CKPT
  
  Userthreads
  address          flags   sessid   user     tty      wait
  tout locks nreads   nwrites
  ...
  7000000204cc968  ---PX-- 39       username    1        0
  0    4     130544   101551
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of Informix Server prior to 14.10.xC4.                 *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Update to Informix Server 14.10.xC4.                         *
  ****************************************************************
  Customers can work around this problem by setting the following
  onconfig params:
  
  PFSC_BOOST 0
  PFSC 0
  

Problem conclusion

• Fixed in Informix Server 14.10.xC4.
  

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