How to avoid SQL4302N caused by Java heap exhaustion when running Java routines in parallel.

Troubleshooting

Problem

An application that calls Java routines has been running for a while without an error, but it start failing with SQL4302N on some connections.

A connection receiving SQL4302N continue to fail with the same error, while other connections are unaffected.

Symptom

An application that runs Java routines(Stored Procedures or UDFs) might receive a similar message like below.

----------------------------------------------------------------------
SQL4302N Procedure or user-defined function "<fuction schema>.<udf name> specific
name "SQLXXXXXXXXXXXXXXX" aborted with an exception "Java heap space".
SQLSTATE=38501
----------------------------------------------------------------------

At the same time, the following error will be recorded in db2diag.log.
----------------------------------------------------------------------
2019-04-09-00.19.47.520000-420 I6227F421            LEVEL: Warning
PID     : 5556                 TID : 4796           PROC : db2fmp64.exe
INSTANCE: DB2                  NODE : 000           DB   : XXXX
APPID   : *LOCAL.DB2.190409070610
HOSTNAME: XXXXXX
EDUID   : 4796
FUNCTION: DB2 UDB, BSU Java support, sqlejCallJavaRoutine_dll, probe:370
DATA #1 : String, 35 bytes
Java routine exited with exception.

2019-04-09-00.19.47.520000-420 E6650F492            LEVEL: Warning
PID     : 5556                 TID : 4796           PROC : db2fmp64.exe
INSTANCE: DB2                  NODE : 000           DB   : XXXX
APPID   : *LOCAL.DB2.190409070610
HOSTNAME: XXXXXX
EDUID   : 4796
FUNCTION: DB2 UDB, BSU Java support, sqlejLogExceptionToDiag, probe:1480
MESSAGE : ADM10000W A Java exception has been caught. The Java stack
          traceback has been written to the db2diag log file.

2019-04-09-00.19.47.520000-420 E7144F466            LEVEL: Warning
PID     : 5556                 TID : 4796           PROC : db2fmp64.exe
INSTANCE: DB2                  NODE : 000           DB   : XXXX
APPID   : *LOCAL.DB2.190409070610
HOSTNAME: XXXXXX
EDUID   : 4796
FUNCTION: DB2 UDB, BSU Java support, sqlejLogExceptionToDiag, probe:1488
DATA #1 : String, 82 bytes
java.lang.OutOfMemoryError: Java heap space
        at <library name>.<udf name>(<source file>.java:<line number>)

2019-04-09-00.19.47.520000-420 I7612F496            LEVEL: Warning
PID     : 5556                 TID : 4796           PROC : db2fmp64.exe
INSTANCE: DB2                  NODE : 000           DB   : XXXX
APPID   : *LOCAL.DB2.190409070610
HOSTNAME: XXXXXX
EDUID   : 4796
FUNCTION: DB2 UDB, routine_infrastructure, sqlerJavaCallRoutine, probe:30
MESSAGE : Error from DB2ER CallUDF. RC:
DATA #1 : Hexdump, 4 bytes
0x0000007315DF5520 : 32EF FFFF                                  2...
----------------------------------------------------------------------

Or if we couldn't even allocate Java heap to create a Java thread, you will see the following error.
----------------------------------------------------------------------
2019-02-22-13.02.03.605000+540 I53710303F361        LEVEL: Warning
PID     : 10928                TID : 10932          PROC : db2fmp64.exe
INSTANCE: DB2                  NODE : 000
HOSTNAME: XXXXXXXX
EDUID   : 10932
FUNCTION: DB2 UDB, routine_infrastructure, sqlerMasterThreadListener, probe:300
MESSAGE : Java heap is nearly full; no thread created

2019-02-22-13.02.03.605000+540 E53710666F552        LEVEL: Warning
PID     : 1116                 TID : 5652           PROC : db2syscs.exe
INSTANCE: DB2                  NODE : 000           DB   : XXXX
APPHDL : 0-702                APPID: XXXXXXXX.XXXX.190222040206
AUTHID : XXXXX                HOSTNAME: XXXXXXXX
EDUID   : 5652                 EDUNAME: db2agent (XXXX)
FUNCTION: DB2 UDB, routine_infrastructure, sqlerMasterThreadReq, probe:89
MESSAGE : FMP reported it could not create a new thread
DATA #1 : Process ID, 4 bytes
10928

2019-02-22-13.02.03.605000+540 I53711220F547        LEVEL: Severe
PID     : 1116                 TID : 5652           PROC : db2syscs.exe
INSTANCE: DB2                  NODE : 000           DB   : XXXX
APPHDL : 0-702                APPID: XXXXXXXX.XXXX.190222040206
AUTHID : XXXXX                HOSTNAME: XXXXXXXX
EDUID   : 5652                 EDUNAME: db2agent (XXXX)
FUNCTION: DB2 UDB, routine_infrastructure, sqlerGetFmpThread, probe:6413
RETCODE : ZRC=0xFFFFFBEE=-1042
SQL1042C An unexpected system error occurred.
----------------------------------------------------------------------

Document Location

Worldwide

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Document Information

More support for:
Db2 for Linux, UNIX and Windows

Software version:
All Versions

Operating system(s):
AIX, HP-UX, Linux, Windows

Document number:
1118955

Modified date:
01 May 2025

UID

ibm11118955

IBM Support

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