IT08467: SEGV POSSIBLE IN DBS_TOTAL_SPACE WHEN CREATING OBJECT USING AUTOLOCATE FEATURE WHILE CONCURRENTLY ADDING A DBSPACE

APAR status

• Closed as program error.

Error description

• A session attempting to create a table/index that is using the
  autolocate feature can generate a SEGV in dbs_total_space() due
  to a timing problem with a 2nd thread attempting to add a
  dbspace.
  
  Stack trace of the crashing thread would look something like
  this:
  
  afstack
  mt_ex_throw_sig
  afsig_handler
  <signal frame>
  dbs_total_space
  rs_locate_idx
  makedetach
  concreatidx
  dounique
  creatab
  aud_creatab
  excommand
  sq_execute
  sqmain
  spawn_thread
  th_init_initgls
  startup
  
  or
  
  afstack
  mt_ex_throw_sig
  afsig_handler
  <signal frame>
  dbs_total_space
  rs_locate_rrfrag
  st2cb
  tab2cb
  stmt2cb
  p_sp2cb
  parsecmd
  sqcmd
  sq_cmnd
  sq_prepare
  sqmain
  listen_verify
  spawn_thread
  th_init_initgls
  startup
  
  current SQL for AF'ing session:
  
    CREATE COLLECTION "d_35976558867.system.users" TABLE
  system_users (id
      CHAR(128) PRIMARY KEY NOT NULL, data bson, modCount BIGINT,
  flags INT)
      EXTENT SIZE 64 NEXT SIZE 64 LOCK MODE ROW
  
  Session attempting to add dbspace:
  
    execute function task("create dbspace from storagepool",
  "newdbs1", "10
      MB")
  
  *Note it doesn't need to be a session adding a dbspace via the
  admin task, a regular onspaces -c -d would also cause problems.*
  
  top portion of stack for thread attempting to add space:
  
  yield_processor_mvp
  mt_lock_wait
  mt_lock
  rschkadd
  aud_ischkadd
  admin_dbs_create
  admin_create_dbspace_from_storagepool
  do_job_cc
  admin_cc
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users running with AUTOLOCATE set in a DDL-intensive         *
  * environment with spaces being added or dropped               *
  * simultaneously.                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Update to IBM Informix Server 12.10.xC6                      *
  ****************************************************************
  

Problem conclusion

• Problem Fixed In IBM Informix Server 12.10.xC6
  

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

  IFMX ULT WHSE E

• Fixed component ID

  IM0019BOS

Applicable component levels

• RC10 PSN

     UP

• RC10 PSY

     UP