GoldenGate

Oracle GoldenGate data filtering with WHERE and FILTER parameters the right way

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One of the most trivial tasks for data replication is to define a replica of the table with just a subset of the rows from the source table. For example we would like just to replicate the ACCOUNTS table with some type (one column has some defined value). If you want to replicate that using Oracle GoldenGate and the account type may be modified then this is one of the most difficult tasks to achieve… Let’s find out why.

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Oracle GoldenGate point in time source database recovery

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Even though you would like to secure the database from any disaster with HA, still it might happen that the database gets corrupted and a recovery from backup is needed to recover the database. In a critical scenario you might need to use Point In Time Recovery (PITR).

Let’s focus on a scenario when the source database needs to be recovered from backup to an earlier point in time. How to resync a replication to the target  database  without the need of a  full initial load?

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Oracle GoldenGate Coordinated Replicat – is it a fully transactional replication?

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Oracle GoldenGate till version 11.2 could only work serially. The only way of creating parallel replication and speeding up the apply process was to create multiple Replicat processes. In version 12.1 there was a new option available: the Coordinated Replicat. It is often misunderstood as a way of speeding up transactional replication. But … is this way of replication fully ACID complaint? Let’s find out.

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Oracle GoldenGate Integrated Replicat and NOSCHEDULINGCOLS

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According to the documentation it is not allowed to use NOSCHEDULINGCOLS with ADD TRANDATA when you would use Integrated Replicat. Why would Oracle care for that? Let’s find out what can happen if you don’t apply the rules.

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Oracle GoldenGate remote Classic Extract

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Most people I have spoken to are are absolutely convinced that the Extract process has to be running on the source database host. This thinking comes from all Oracle diagrams where the Extract process is located on the source database host. Till OGG version 11.1.1 this was indeed true. Some have heard that the Extract process can be removed from the source host but it can only done with the Integrated Extract process.

There is however the TRANLOGOPTIONS DBLOGREADER parameter which allows the Classic Extract can be run remotely without any need of accessing the redo/archive logs file system (or ASM).

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How Oracle GoldenGate Replicat handles Foreign Key Constraints

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According to the Oracle database documentation there are two types of constraints: DEFERRED and NOT DEFERRED. The first one can be evaluated at the and of the transaction, and the second one if validated immediately. On the other hand Oracle GoldenGate can handle the replication when the target uses both of them. Let’s find out how this works.

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