IT31485: CONTENTION ON SQLO_LT_SRVLST_CB__SRVLSTLATCHL LATCH DURING SSL CONNECTIONS

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 program error.

Error description

• During SSL connections, there may be some contentions observed
  which are resulted from SQLO_LT_SRVLST_CB__srvLstLatchl latch
  waits.
  
  This latch is held during the reading for SSL port number entry
  in /etc/services file upon db2 database connection. And for any
  reason, the read I/O is taking long, and there is high
  concurrency in number of connections to the database, then
  longer latch waits on SQLO_LT_SRVLST_CB__srvLstLatchl can be
  observed, causing longer connection times.
  
  This defect will add an enhancement to not read SSL port number
  from /etc/services file upon each connection, but rather load it
  into the memory upon the first connection and be used by
  subsequent connections.
  
  db2pd -latches output collected during the issue, may show the
  following output:
  
  0x0780000000470D68 1183602    84416      sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    165652     sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    155143     sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    91878      sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    185478     sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    286680     sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    425941     sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    269915     sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    125267     sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    128346     sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    78456      sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    261764     sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    289963     sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    85535      sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    111414     sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    175238     sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    194977     sqleu_serverd.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    219593     sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  0x0780000000470D68 1183602    245242     sqleu_server.C
  6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
  

Local fix

• As a temp workaround, SSL port number can be bumped up inside
  /etc/services file to help reads be faster.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users on DB2 v111m4FP5 and earlier                       *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to DB2 v111m4FP6 or apply Local Fix is available     *
  ****************************************************************
  

Problem conclusion

• First Fixed in DB2 v111m4FP6
  

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

• Fixed component name

  DB2 FOR LUW

• Fixed component ID

  DB2FORLUW

Applicable component levels

• RB10 PSY

     UP

• RB50 PSY

     UP