PM98429: DICTIONARY PAGES ACCESSIBILITY ENHANCEMENTS

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• Dictionary Pages accessibility enhancements
  (DCR DM1784)
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: DB2 10 for z/OS (CM and NFM) and DB2 11 for  *
  *                 z/OS users of compressed table spaces and    *
  *                 replication                                  *
  ****************************************************************
  * PROBLEM DESCRIPTION: This APAR implements the following      *
  *                      enhancements:                           *
  *                                                              *
  *                      (1). DB2 10 (CM and NFM) and DB2 11:    *
  *                           Allow IFI 306 (for QRep) to be     *
  *                           able to decompress compressed logs *
  *                           for user table spaces that are in  *
  *                           group buffer pool RECOVER-pending  *
  *                           status (GRECP)                     *
  *                                                              *
  *                      (2). DB2 10 (NFM) and DB2 11:           *
  *                           For the purposes of replication    *
  *                           to a second site via peer-to-peer  *
  *                           remote copy (PPRC), allow          *
  *                           compress-on-insert dictionary      *
  *                           pages (built starting in DB2 10    *
  *                           NFM by SQL INSERT or online LOAD   *
  *                           utility) to be written to DASD     *
  *                           as soon as the pages are built     *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  (1)
  
  Today, QREP Capture sends requests to IFI 306 for decompressed
  DB2 log data. For compressed tables, IFI 306 needs to access
  compression dictionaries to decompress log records before
  returning log data to QREP.
  
  Prior to this APAR, for pagesets or partitions that are in GRECP
  state, DB2 does not allow IFI 306 to access dictionary pages.
  The enhancement in this APAR is to allow access in such case.
  
  The reason is that, once a dictionary is built and written to
  DASD, it will not be updated during SQL mainline operations and
  there should be no updates on dictionary pages. So it would be
  safe for IFI 306 to access compression dictionaries even for
  table spaces that are in GRECP state (provided that the catalog
  or directory objects in databases DSNDB01 and DSNDB06 are not in
  any restrictive state).
  
  (2)
  
  DB2 10 NFM introduced the new compress-on-insert function which
  allows a compression dictionary to be built by SQL insert or by
  online LOAD utility. In a data sharing environment, the
  compress-on-insert dictionary pages are only written to group
  buffer pool after the dictionary is built.
  
  In order to allow compress-on-insert dictionary pages to be
  replicated to a second site via PPRC, in data sharing DB2 needs
  to be enhanced to write out compress-on-insert dictionary pages
  from group buffer pool to DASD immediately.
  

Problem conclusion

Temporary fix

Comments

• DB2 code has been enhanced as follows:
  
  (1) Allow QREP to access compression dictionaries from table
  spaces that are in GRECP state, if the catalog and directory
  objects (in databases DSNDB01 and DSNDB06) are not in any
  restrictive state.
  
  (2) For the purposes of replication to a second site via PPRC,
  in a data sharing system, write out compress-on-insert
  dictionary pages from group buffer pool to DASD immediately.
  
  Additional keywords: IFCID306
  

APAR Information

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

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

  UI12050 UI12051

Modules/Macros

• DSNB1CLM DSNB1OPP DSNIDBCO DSNIDBCQ DSNISMRT DSNIZLDL
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RA10 PSY UI12050

     UP13/11/19 P F311

• RB10 PSY UI12051

     UP13/11/16 P F311

Fix is available

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