Database Compare Technology — Overview

Shadowbase-Database-Compare-Technology - CopyHPE Shadowbase Compare is a suite of utility products that allows you to compare a target Enscribe file or NonStop SQL table to its source, and reports on all discrepancies found between the two. Discrepancies may occur, for example, if the user accidentally purges necessary audit trails. Shadowbase Compare is helpful for validating that a target database matches its source, and for satisfying regulatory requirements for data verification. It is meant for comparing HPE NonStop to HPE NonStop, like-to-like source/target environments where Expand is available between the nodes (for example, for business continuity environments). There is limited support for SQL environments where only TCP/IP is available between the systems.

The Shadowbase Compare suite consists of Shadowbase Compare SQL/MP, Shadowbase Compare SQL/MX, and Shadowbase Compare Enscribe. The basic method of comparison is similar for each product in the suite: the contents of the specified target file or table (or subset key range thereof) 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 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 but the data contents do not, are summarized and optionally reported in various report output modes (summary reports of counts of differences as well as optionally a detailed report of the differences). One set of specific files or tables is compared at a time for each comparison run, although many comparisons can be run in parallel.

Note that, at this time, the entire source record or row is compared against the entire target record or row.  Shadowbase Compare does not compress or condense many records or rows into a checksum and compare just the checksum. This form of comparison is under consideration for a future release.

For each of the Shadowbase Compare products, the source and the target environments need to 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.

Data replication of the source or target file or table can be active at the time of the comparison. Comparisons made when a record or row is being updated will be flagged as potential mismatches. When run in a data replication environment where the source database is actively being updated, Shadowbase Compare has various features to eliminate or reduce “false positives” and to minimize them in the final report.


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