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PM98429: DICTIONARY PAGES ACCESSIBILITY ENHANCEMENTS

A fix is available

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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 number

    PM98429

  • Reported component name

    DB2 OS/390 & Z/

  • Reported component ID

    5740XYR00

  • Reported release

    A10

  • Status

    CLOSED UR1

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-10-03

  • Closed date

    2013-10-31

  • Last modified date

    2013-12-02

  • 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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Document information

More support for: DB2 for z/OS

Software version: 10.1

Reference #: PM98429

Modified date: 02 December 2013