Info Mart Database Replication [DRAFT]
Contents
About Oracle GoldenGate
Genesys recommends that you use Oracle GoldenGate to achieve database replication for Genesys Info Mart. Oracle GoldenGate was selected as the replication tool because it is able to replicate a subset of database tables, thus saving the bandwidth that is required for data replication.
Note: Genesys has verified the Info Mart replication with Oracle GoldenGate version 11.2.1.0.1.
Tables Excluded from Replication
The Info Mart database in a large environment grows over time to a significant size. A large portion of the Info Mart tables contain raw data that Genesys Info Mart uses for internal processing and that is not suitable for end-user reports. For this reason, Genesys recommends that you limit the set of tables that are replicated to the standby site, replicating only the dimensional model and aggregate tables, and excluding from replication all Temporary tables, as well as certain GIDB, Merge, Staging, and Control tables.
Genesys recommends that you exclude the following tables from Oracle GoldenGate database replication, for performance reasons.
Temporary tables
Exclude all Temporary tables (that is, all tables that have names that start with TMP_*).
GIDB tables
Exclude the majority of GIDB tables.
Aggregate tables
In deployments with RAA/GI2, exclude certain aggregate tables.
Merge tables
Exclude the majority of Merge tables.
Staging tables
Exclude several Staging tables.
Control tables
Exclude certain Control tables.
Potential Data Loss
As discussed above, certain tables, which are mostly internal, are not replicated to the target database. Additionally, extraction of data for any given time period is a one-time operation: Genesys Info Mart does not go back to re-extract data for a time period that has already been extracted. After a site failure, the newly active Genesys Info Mart will not re-extract the data that the failed Genesys Info Mart had previously extracted. This design, which is intended to improve performance, brings a risk of reporting data being lost during Disaster Recovery.
In essence, any data that has not been delivered to the target Info Mart database by the time of the disaster event may be lost.
In the case that some data has not been extracted yet, and an HA IDB was set up at Site 2, any data that has not been extracted previously will be extracted after the Genesys Info Mart at Site 2 is brought into service. When no HA IDB is available at Site 2, all Site 1 data that was not extracted will be lost.
In the case that IDB data was extracted, the data might or might not have been transformed, or if the data was transformed, it might or might not have been replicated to the target database yet. All extracted data that has not been transformed will be lost. Similarly, all extracted data that was transformed but, because of some delays, has not been delivered to the target database by the time the disaster occurred, will be lost.
The time that it takes to replicate the processed data to the target database plays a role in data availability as well. Under certain circumstances, delay in data replication may result in the standby Info Mart database having an earlier high-water mark than the active database has for extracted data. In this case, the Genesys Info Mart that is brought into service at Site 2 can potentially extract from the redundant IDB at Site 2 a subset of data that was previously extracted from the Site 1 IDB.