Getting started

BMC developed a product line to respond to the needs of DBAs, system administrators, and other Db2 users who require high-performance database administration and utility products. The CHECK PLUS product provides a high-performance tool with a full range of integrity-checking functions.

CHECK PLUS addresses the following types of integrity checking needed to fully support critical Db2 applications. For more information, see Types-of-checking.

  • Checking the structural integrity of the data sets that contain Db2 objects
  • Verifying that indexes and the data to which they refer are consistent
  • Verifying that data in Db2 tables does not violate referential integrity (RI) constraints or table check constraints

CHECK PLUS combines these integrity checking functions, replacing functions provided by the CHECK option of the DSN1COPY stand-alone Db2 utility, and by the IBM Db2 CHECK INDEX and CHECK DATA utilities. It also provides the increased flexibility of allowing you to specify which of the checks should be performed.

Combining functions currently performed by separate utilities gives CHECK PLUS significant performance advantages. For example, you can check the structural integrity of both table space pages and index pages concurrently. CHECK PLUS can also check the integrity of the table space and index pages it reads while checking for data violations.

In addition to performing the standard RI checking functions, CHECK PLUS can check referential constraints that are not defined within the Db2 subsystem and perform column data verifications. This functionality gives you the advantage of checking business rules without paying the performance penalty of processing with referential constraints defined. This functionality is also beneficial for applications that were implemented before Db2 offered RI support.

To provide maximum data availability, CHECK PLUS can use the snapshot-processing feature of the BMC SNAPSHOT UPGRADE FEATURE  (SUF) (also known as XBM) product. This snapshot feature allows you to perform all integrity-checking functions while the data remains available for read and write purposes. 

Tasks that CHECK PLUS performs

CHECK PLUS performs the following integrity checking tasks on Db2 table spaces, tables, and indexes, and offers several functional enhancements over alternative checking methods:

Task

Description

Checking objects of data

  • Provides a comprehensive check of table spaces and indexes to ensure a correct structure and consistency between space maps and data pages
  • Provides checking of column data through both the VERIFY option and support of table check constraints
  • Provides RI checking of related tables, whether the RI is maintained by Db2 or user-written application programs
  • Generates a sequential file containing foreign keys in RI violation that you can use later to correct the tables

  • Provides an SQL batch execution program for deleting rows with foreign key violations

    Important

    For a summary table of the items checked by each level of CHECK PLUS, see Types of checking by command. For detailed information about the specific items checked by each level of CHECK PLUS, see Fields-and-values-checked-in-tables-and-indexes.

Object availability

  • Uses the snapshot functionality of the BMC SUF (also known as XBM) product to optionally perform checking while the data is available for read and write purposes 
  • Runs concurrently with other BMC utilities on Db2 spaces

Resources

Optionally offloads eligible processing to a zIIP

Performance

  • Provides options for narrowing the range of checking to reduce execution time
  • Allows for concurrent execution of checking functions

Statics and reports

  • Issues diagnostic messages that detail the results of checking processes
  • Allows you to customize the severity level of many of the CHECK PLUS diagnostic messages
  • Maintains a table of statistics history on all previous CHECK PLUS activities

This section contains the following topics:

 

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