APAR status
Closed as program error.
Error description
It is expected behavior that when an instance of IDS is started with the oninit -s command (or the onmonitor->Mode->Startup equivalent), it will not start the btree scanner thread(s). When converting an IDS instance from 11.70.xC1/2 to 11.70.xC3 or higher, it goes through special conversion code. When this special conversion code is complete, it marks the instance as OnLine and starts the dbScheduler threads but it does not start the btree scanner thread(s). The above scenario in and of itself is not fatal. But because it does not start the btree scanner threads, it also does not initialize the necessary btree scanner structures in shared memory. And because it does not initialize the btree scanner shared memory structures, there are some side effects: 1) Because the btree scanner thread is responsible for removing deleted index keys and keeping indices from becoming severely bloated and therefore less efficient, this can lead to performance problems. 2) A query of the sysmaster:sysshmhdr pseudo table directly references the uninitialized btree cleaner memory structure and will segv and crash the IDS instance (example stack is included later in the description) 3) The onstat -C command will not work, reporting only "Changing data structure forced command termination". After the fact, any of these problems can avoided by starting the instance before conversion with "oninit" or by taking the instance offline after conversion (assuming started with oninit -s) and bringing it back up with "oninit". Simply starting the btree scanner thread(s) with onmode -C start will also crash the IDS instance. dbScheduler has a task called mon_profile which is enabled by default to run every 4 hours. This task does a query of the sysmaster:sysshmhdr pseudo table which will induce the crash. The crash looks something like this: 20:55:10 Assert Failed: Exception Caught. Type: MT_EX_OS, Context: mem 20:55:10 Who: Session(127, informix@, 0, 0x4ddf5088) Thread(141, dbWorker2, 4ddb6e00, 20) File: mtex.c Line: 416 20:55:10 Action: Please notify IBM Informix Technical Support. 20:55:10 Raw hex dump of stack located in /home/informix/tmp/af.4756d8e.rawstk 20:55:10 Stack for thread: 141 dbWorker2 base: 0x000000005063f000 len: 135168 pc: 0x0000000001317a03 tos: 0x0000000001c2a030 state: running vp: 20 afstack afhandler affail_interface mt_ex_throw_sig afsig_handler <signal frame> prshmhdr pstread pst_rsread rsread fmread readseq_single gettupl scan_next insert_next doinsert excommand sq_execute mi_exec ph_execute do_sensor db_sch_worker udrlm_clang_execute_internal udrlm_clang_execute udrlm_exec_routine udr_execute dbsched_start_udr th_init_initgls startup
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: * * users converting from 11.70 * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Update to IDS-11.70.xC9 * ****************************************************************
Problem conclusion
Problem Fixed In IDS-11.70.xC9
Temporary fix
Comments
APAR Information
APAR number
IT00315
Reported component name
INFORMIX SERVER
Reported component ID
5725A3900
Reported release
B70
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2014-03-13
Closed date
2016-12-09
Last modified date
2016-12-09
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
RB70 PSN
UP
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Document Information
Modified date:
09 December 2016