IT31808: TRAP MAY HAPPEN WHEN RUNNING DB2EXPLN BY '-CACHE' OPTION WITH WRONG ENVIRONMENT ID

Db2 Version 11.1 Mod 4 Fix Pack 6 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 6 for Linux, UNIX, and Windows

APAR status

• Closed as fixed if next.

Error description

• TRAP may happen when running db2expln by '-cache' option with
  wrong environment ID.
  The stack pattern is like below.
  
  ..
  sqloEDUCodeTrapHandler
  _Z18sqlra_hash_loc_envP8sqlrr_cbP14sqlra_cmpl_envP17sqlra_cached
  _stmtibPP16sqlra_cached_envS7_PiPm
  _Z18sqlra_find_var_envP8sqlrr_cbP17sqlra_anchor_stmtP17sqlra_cac
  hed_stmtP13sqlra_stmt_idjP14sqlra_cmpl_env15sqlra_fill_modebbPiS
  A_PP16sqlra_cached_envSA_Pm
  _Z14sqlra_find_varP8sqlrr_cbP17sqlra_cached_stmt13sqlra_stmt_idj
  jPhjthP14sqlra_cmpl_env15sqlra_fill_modePiiS8_iiiS8_P14SQLP_LOCK
  _INFOPP16sqlra_cached_varS8_bSA_Pb
  sqlra_get_sql_cache_sect
  _Z29sqlerTrustedRtnCallbackRouterjPPv
  sqlCache
  ..
  
  The example reproduction scenario is like below.
  
  - connect to a db
  - issue a dynamic SQL statement
  - issue db2pd -db <dbname> dynamic and in the Dynamic SQL
  Variations find the AnchID/StmtID/EnvID/VarID of a variation in
  the cache.
  
  For example, from this part of the output:
  
  Dynamic SQL Variations:
  Address            AnchID StmtUID    EnvID      VarID
  NumRef     Typ Lockname                   Val Insert Time
  Sect Size  Num Copies
  0x00007FFEFA17C0A0 68     1          1          1          1
  1   010000000100000001008008D6 Y   2020-02-04-10.09.29.589167
  1928       0
  
  There is an entry in the cache with a AnchID/StmtID/EnvID/VarID
  of 68,1,1,1.
  
  Running the following command, db2explan generates the section
  from the cache explained.
  
  db2expln -d <dbname> -cache 68,1,1,1 -o expln.out
  
  Specifying an ID that is not in the cache should result in a
  "Section not found in SQL cache" message in the expln.out file.
  This will happen, for example if the following is specified:
  
  db2expln -d <dbname> -cache 68,20,1,1 -o expln.out
  
  However if one specifies a correct anchor ID and statement ID,
  but the environment ID is not in the cache, the trag may occur.
  
  db2expln -d <dbname> -cache 68,1,33,1 -o expln.out
  

Local fix

• Running 'db2expln' with correct environment ID.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All platform                                                 *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to V11.1 mod4 fixpack 6                              *
  ****************************************************************
  

Problem conclusion

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

Applicable component levels

• RB10 PSN

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