Creating EA-enabled table spaces and index spaces

DFSMS has an extended-addressability function, which is necessary to create data sets that are larger than 4 GB. Therefore, the term for page sets that are enabled for extended addressability is EA-enabled.

About this task

You must use EA-enabled table spaces or index spaces if you specify a DSSIZE that is larger than 4 GB in the CREATE TABLESPACE statement.

Procedure

To create EA-enabled page sets:

  1. Use SMS to manage the data sets that are associated with the EA-enabled page sets.
  2. Associate the data sets with a data class (an SMS construct) that specifies the extended format and extended addressability options.

    To make this association between data sets and the data class, use an automatic class selection (ACS) routine to assign the Db2 data sets to the relevant SMS data class. The ACS routine does the assignment based on the data set name. No performance penalty occurs for having non-EA-enabled Db2 page sets assigned to this data class, too, if you would rather not have two separate data classes for Db2.

    For user-managed data sets, you can use ACS routines or specify the appropriate data class on the DEFINE CLUSTER command when you create the data set.

  3. Create the partitioned or LOB table space with a DSSIZE of 8 GB or greater. The partitioning index for the partitioned table space takes on the EA-enabled attribute from its associated table space.

    After a page set is created, you cannot use the ALTER TABLESPACE statement to change the DSSIZE. You must drop and re-create the table space.

    Also, you cannot change the data sets of the page set to turn off the extended addressability or extended format attributes. If someone modifies the data class to turn off the extended addressability or extended format attributes, Db2 issues an error message the next time that it opens the page set.

Creating partitioned table spaces that are enabled for EA

The following CREATE TABLESPACE statement creates an EA-enabled table space, SALESHX. Assume that a large query application uses this table space to record historical sales data for marketing statistics. The first USING clause establishes the MYSTOGRP storage group and space allocations for all partitions:

CREATE TABLESPACE SALESHX
  IN MYDB
  USING STOGROUP MYSTOGRP
    PRIQTY 4000
    SECQTY 130
    ERASE NO
  DSSIZE 16G
  NUMPARTS 48
    (PARTITION 46
     COMPRESS YES,
    PARTITION 47
     COMPRESS YES,
    PARTITION 48
     COMPRESS YES)
  LOCKSIZE PAGE
  BUFFERPOOL BP1
  CLOSE NO;