|
Problem IC63997
|
Status: Closed |
AGENT HANG MIGHT HAPPEN BETWEEN TWO PROCESSES WHEN THEY ARE PERFORMING DYNAMIC SQL COMPILE. |
| product: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problem description: |
There is a very small time frame that a deadlatch (latch waiting
loop, similar to deadlock) might happen between two agent
processes if they are performing dynamic SQL compile.
The following conditions concurrence will probably lead to
deadlatch.
- the two applications involved must be compiling the same
statement.
- the statement includes a reference to a procedure, function or
method.
- the two agent processes are performing any dynamic SQL compile
(which includes PREPARE or EXECUTE IMMEDIATE).
The deadlatch scenario can be described as follow.
Process A is holding latch SQLO_LT_sqlra_cached_stmt__latch and
waiting latch SQLO_LT_sqlra_cached_env__latch.
While another process B is holding and waiting latch conversely.
This type of deadlatch will cause some applications hang.
The latch holding and waiting information can be obtained in
trap files.
Here is an example for this deadlatch:
pid process name holding latch name
waiting latch name
------- ---------------- --------------------------------
--------------------------------
1111111 db2agent (SAMPL) SQLO_LT_sqlra_cached_stmt__latch
SQLO_LT_sqlra_cached_env__latch
2222222 db2agent (SAMPL) SQLO_LT_sqlra_cached_env__latch
SQLO_LT_sqlra_cached_stmt__latch
Here is a possible stack trace of pid 1111111:
=========================
sqloXlatchConflict
sqloXlatchAIX
sqlra_find_var_var
sqlra_find_var
sqlra_get_var
sqlrr_prepare
sqljs_ddm_prpsqlstt
sqljsParseRdbAccessed
sqljsParse
=========================
Here is a possible stack trace of pid 2222222:
================================
sqloXlatchConflict
sqloXlatchAIX
sqlra_compare_env_routine_auths
sqlra_compare_env_routine_auths
sqlra_hash_loc_env
sqlra_cache_ins_env
sqlra_find_var_env
sqlra_find_var
sqlra_get_var
sqlrr_prepare
sqljs_ddm_prpsqlstt
sqljsParseRdbAccessed
sqljsParse
================================ |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* any *
****************************************************************
* PROBLEM DESCRIPTION: *
* presents as a hang *
****************************************************************
* RECOMMENDATION: *
* upgrade to DB2 for LUW v97 fp1 *
**************************************************************** |
| Local Fix: |
|
| available fix packs: |
DB2 Version 9.7 Fix Pack 1 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 2 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 3a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 4 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 5 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 7 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 9a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 6 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 8 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 9 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 10 for Linux, UNIX, and Windows
|
| Solution |
fixed in DB2 for LUW v97 fp1 |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 22.10.2009
18.02.2010
18.02.2010 |
| Problem solved at the following versions (IBM BugInfos) |
9.7.FP1
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.7.0.1
|
 |
