HPE Shadowbase Database Compare and Repair Overview

Stock photo of woman comparing height of two glasses of waterHPE Shadowbase Compare

HPE Shadowbase Compare is a utility that compares two HPE NonStop databases (Enscribe and/or SQL) and reports any discrepancies, which may occur, for example, if either a disaster corrupts one of the databases, or a user misconfigures the application or replication environment. Applications may remain active on both the source and target, even for updating, while the comparison takes place.

Shadowbase Compare validates that a target database matches its source, and may be used to help satisfy regulatory and audit requirements for data verification. Since Shadowbase Compare works while any data replication product is replicating between the databases, it can also be used to validate an online business continuity replication configuration. It is designed for comparing like-to-like environments, such as HPE NonStop to HPE NonStop source/ target (e.g., for Enscribe-to-Enscribe or SQL-to-SQL business continuity). Shadowbase Compare works across TCP/IP and/or Expand connectivity; however, there is limited support for SQL environments if only TCP/IP is available between the systems.

The HPE Shadowbase Compare utility consists of Shadowbase Compare SQL/MP, Shadowbase Compare SQL/MX, and Shadowbase Compare Enscribe. The basic method of comparison is similar for each utility: the contents of the specified target file or table (or subset key range) is read and compared against the contents of the specified source file or table. In some cases, the data to be compared can be compressed to lessen the network load.  The “polarity” of which file or table is the source versus the target can be changed, and a comparison can be re-run if so desired.

Shadowbase Compare produces a summary report of counts of differences as well as optionally a detailed report of the specific differences. One set of files or tables (or key ranges) is compared at a time for each comparison run, although many comparisons can be run in parallel against the same table set, for example using a partition break scheme. For more information, please reference our HPE Shadowbase Compare Solution Brief or contact us.

HPE Shadowbase Repair

HPE Shadowbase Repair is a feature in the HPE Shadowbase Compare for SQL NonStop Utility to assist with correcting or repairing SQL/MP or SQL/MX database discrepancies between two tables. This feature works on any two database tables, provided they are both of the same type (MP or MX). It does not require to be run in a Shadowbase replication architecture, and can be used in any environment where a source and target table need to be verified.

HPE Shadowbase Repair is particularly useful in business continuity data replication environments to provide confidence (or certification) that the source and target data matches, and to repair the discrepancies when it does not. HPE Shadowbase Compare reports the discrepancies between two sets of SQL tables, which would be an error-prone and time-consuming task to correct if even only a handful of differences were found. With HPE Shadowbase Repair, the user can automatically and quickly correct these differences with just a few simple commands. For more information, please reference our HPE Shadowbase Repair Solution Brief or contact us.

With Shadowbase Compare and Repair, the user has full control over selecting which table is considered the source, and which table is considered the target. With Repair, the options for repairing the discrepancies (in order of suggested usage) include:

  • Option 1: Updating the Source Data with a NO-OP Update

This approach is suggested when the source and target databases have the same or different format and while a replication engine is running. Update the source data with a “NO-OP” update, using the values in the source table (i.e., setting the source data to the same values). The replication engine replicates the source update to the target to make the target consistent.

  • Option 2: Updating the Target Data Directly

This approach is suggested when the source and target databases have the same format and when replication is not running. Update the target data directly, using the values in the source table.

  • Option 3: Updating the Target Data with a NO-OP Update

This approach assumes and requires replication properly configured and running in a bi-directional environment. Update the target data with a “NO-OP” update, using the values in the target table. The replication engine will replicate the target update to the source to make the source consistent.

  • Option 4: Updating the Source Data Directly

This approach assumes there is no replication engine running and is symmetrical to “Updating the Target Data Directly.” Update the source data directly, using the values in the target table.

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