Figure 1 depicts a typical HPE Shadowbase Online Loader and Verification (SOLV) offline loading scenario. An application posts its changes to a source database. SOLV takes a copy of the load data at a point-in-time and performs data and similar other transformations; then the Shadowbase replication engine prepares and applies the data into the target database. In this example, a point-in-time copy of the source database (load data) is taken and applied into a target database environment by SOLV and the Shadowbase replication engine.
This form of loading is referred to as offline because any application changes made to the source database by the application after the load starts (and after the data has been loaded) will not subsequently be replicated into the target database. This form of loading is most suitable when the source database is not actively being updated, or when a point-in-time snapshot of the source database is required.
SOLV allows the entire source file/table (or key ranges) to be specified for the load. Limited source data filtering (e.g., by partition, or data content) is also supported – please see the SOLV solution brief. Additionally, the target database can be empty or contain data when the load starts. To refresh the target data, SOLV will overwrite existing data with incoming data from the source database. If additional data exists in the target database that is neither in the source database nor necessary to current operations, then the user should delete that target data before performing the load or refresh operation. If the additional data is important, of course, it should be saved somewhere else before deletion.
Figure 2 depicts a SOLV example of online loading. An application is actively processing user requests and reading and/or updating the source database. Note that the application has full access to the source database and optionally the target database while the load progresses. The Shadowbase replication engine is responsible for preparing, transforming, and merging the application’s source database changes (DML and DDL activity). These changes are collected with the data being loaded by the Collector process, which runs on the source system’s hardware in the Audit Trail or other database change log, (e.g., DB2’s journal files, or Oracle’s Redo Log). The changes are then applied as a merged stream into the target database. SOLV is loading the source database into the target database via the Shadowbase replication engine’s Consumer process, which runs on the target system. SOLV and the Shadowbase replication engine then keep the target database synchronized with changes made to the source database after the load completes.
SOLV loading utilizes special patented features that allow it to properly merge the data being loaded with the data being replicated. Note however that the SOLV loading can occur without HPE Shadowbase replication being active/in-use. In this case, SOLV acts like a stand-alone data transformation utility, reading and converting the source data format into the target data format, and applying that information into the target environment.
The utility can load audited and non-audited HPE NonStop Enscribe source files and HPE NonStop SQL tables into any target environment and database combination supported by the Shadowbase line of data replication products (e.g., HPE NonStop Enscribe or SQL targets, or Other Server targets such as Oracle, Sybase, SQL Server, DB2, and MySQL).
The Shadowbase ETL utility uses and extends the SOLV loading capabilities to allow for reading and injecting events from flat files into the HPE Shadowbase replication engine for processing, as well as producing flat files of database data or database change events that can then be subsequently processed by an ETL tool.