Sizing Guidelines
Follow these sizing guidelines to configuring Oracle GoldenGate for PostgreSQL.
Prerequisites
Follow the system and sizing requirements in What is Required? in the Oracle GoldenGate documentation.
General Sizing Guidelines
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For memory and CPU, start with 32 GB of memory and 2 CPUs per Extract, because it’s a multithreaded process and uses a large amount of memory when processing large transactions. Depending on the transaction volume and pattern, scale up the resources appropriately following the guidelines in the Oracle GoldenGate documentation.
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For disk space, start with 2 TB, and vary it based on the volume of data that the Extract captures from the source databases. The Extract uses storage for trail files and temporary disk space for cache files if there’s a big transaction to buffer for processing.
Temporary disk space requirements due to large transactions may fill up the cache and spill over to the transaction-cached data or temporary files. Configure an archive policy and define the retention period of the files so they can be recycled accordingly.
Maintain enough physical memory to handle large transactions. According to the guidelines, have at least 32 GB of memory available for the Extract to use. For a more accurate estimation, collect the statistics from the database server history run and check for the size of the biggest transaction. Oracle GoldenGate provides the send <extract> cachemgr, cachestats command that displays the statistics of the transaction, which is helpful to determine the baseline for estimation.
In general, the sizing, storage, and memory for the Oracle GoldenGate Extract process is highly dependent on the transaction volume and transaction pattern. Collect these statistics from every single database server to estimate, because there’s no standard value. The number of databases that can be supported by a single GoldenGate instance or Extract process depends on the system resources that support multiple Extracts. Configure one Extract for every database.