PH44833: NEW FUNCTION FOR LIMITING THE NUMBER OF UDF RUNNING CONCURRENTLY

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• IF ONE SQL STATEMENT CONTAINS UDFs, EACH UDF NEEDS COMMON
  STORAGE IN ECSA.
  THIS WOULD LEAD TO ECSA SHORTAGE. THIS APAR ADD CAPABILITY TO
  CONTROL THE NUMBER OF CONCURRENTLY RUNNING UDF.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All Db2 12 for z/OS and Db2 13 for z/OS                      *
  * users of external user-defined functions.                    *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * ECSA storage shortage can occur when                         *
  * an SQL statement has too many external                       *
  * UDFs.                                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When Db2 processes each external UDF in the query, ECSA
  storage will be allocated for Db2 control blocks. With a large
  number of UDFs, ECSA storage can be exhausted which can bring
  down Db2.
  If a multi-index-access access path is used,
  each UDF in the query could be accessed multiple times.
  The amount of the ECSA storage required is then multiplied.
  

Problem conclusion

Temporary fix

Comments

• A new zparm, DSN6SPRM.MAX_UDF, is introduced which specifies
  the maximum number of external UDFs which can be active in a
  thread.  If the limit is exceeded, Db2 will issue sqlcode
  -904 with reason code 00E70082
  additional keywords: SQLUDF SQLSTORAGE
  ×**** PE23/03/16 FIX IN ERROR. SEE APAR PH53318  FOR DESCRIPTION
  

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UI83589 UI83590

Modules/Macros

• DSNTINMF DSNXESTR DSNDQWPZ DSNWZIFD DSNWZIFC DSNTIDXA DSNTIVMD
  DSNTIJUZ DSNTINST DSNTIDXC DSNTIWIA DSNTIDXB DSNTIVIA DSNTIWMD
  DSNTIWIE DSNTIVIE DSN@XAZP DSN6SPRM DSNTIPX  DSNTXAZP DSNTIWPC
  DSNDSPRM DSNTIVMN DSNTIWMN DSNTIVAF DSNTIVIN DSNX9WCA DSNTIWMS
  DSNTIVMS DSNTIWAF DSNTIWIN DSNXOD5
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RC10 PSY UI83589

     UP22/12/21 P F212

• RD10 PSY UI83590

     UP22/12/21 P F212

Fix is available

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