Unexpected DB2LUW hang while using Vintella Authentication Services plug-in

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There are few  Technote and Document out there  on this already.

But,   wanted to share this  as  some customers still faced this issue lately.

The  symptom is  reported as  sudden hang in  Db2 database.  Nothing progressing.

CPU,  memory and I/O were abnormally idle in the box.

That is an indication that nothing really running  and  stuck some where.

No locking or latching.

A  quick  running  of  "db2pd -stack all"   will dump the db2  thread  stack  files under DIAGPATH directory.

Just  a quick review of  some of the stacks or,    grepping the files with function name "vas_db2_plugin_auth_user" 

might show  the problem quickly.

The stacks will have following kinds of  functions at the top :

 0x09000000007CC738 _global_lock_common + 0x4B8

  0x09000000007F1024 _atfork_prepare + 0x64

  0x0900000000116F20 __fork + 0x40

  0x09000000047DD440 vas_db2_plugin_auth_user + 0x440

  0x09000000047DFE30 vas_db2_plugin_check_password + 0x24C

  0x090000000E096DA8 secValidatePasswordPlugin__FPciT1N22T1T2T1T2T1T2PPvUiT2 + 0xE8

  0x090000000E09709C sqlexValidatePassword__FPciT1N22T1T2T1T2T1T2UiPPvT2 + 0x14C

  0x090000000E0977A4 sqlexSlsSystemAuthenticate__FP14db2UCinterface + 0x238

  0x090000000E098C0C sqlexSlsServerAuthenticate__FP14db2UCinterfacelPUi + 0x1C4

  0x090000000E099770 sqlexEngAuthenticate__FP14db2UCinterface + 0x430

This is due to usage of VAS plugin.

Please refer  :

/support/pages/node/463813

and,

http://rc.quest.com/topics/db2_sys-auth/

Please  do the needful  following those technote/document.

The stacks might vary  depending on the situations.  But, there should a  "vas" and/or  "plugin"  signature in some of the top functions.