HPE Shadowbase Database Compare Overview

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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. 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.

Encountered differences are summarized and optionally reported in various report output modes, such as:

  • records or rows in the source but not in the target
  • records or rows in the target but not in the source
  • records or rows in both whose keys match, however the data contents do not

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.

The entire source record or row can be compared against the entire target record or row in order to determine and display all discrepancies down to the byte level. For large tables that have small differences, Shadowbase Compare SQL can compress many rows into a checksum and only compare the checksum, which will reduce overall network traffic and speed the comparison dramatically.

For each of the Shadowbase Compare utilities, the source and the target environments should be exactly the same, or at least very similar to each other. Shadowbase Compare does not compare heterogeneous environments, although this feature is under consideration for a future product release. If heterogeneous comparison technology is of interest to you, please let us know the source and target platforms, databases, and versions.

The source and target file or table can actively replicate data at the time of the comparison. Comparisons made when a record or row is being updated will be flagged as potential mismatches. Shadowbase Compare has various features to eliminate or reduce “false positives” (records or rows that mismatch due to replication latency) in the final report.


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