![]() Using log-based CDC in Oracle means that the CDC process uses transaction logs to identify and apply changes to target platforms or tables. Log-based Oracle CDC Using Transaction LogsĪside from the two types of CDC mentioned above, log-based approaches can also be used. Using triggers puts a further load on the Oracle database, increasing the overhead of each operation and potentially leading to performance degradation. ![]() One of the major concerns of using this approach is the performance impacts of using triggers. When an insert, update or delete occurs, the trigger writes the changes into another database table with the timestamps and replication is then carried out from the audit table. Oracle CDC can be set to capture changes by using triggers that are defined on the tables you want to replicate. Incorrect replication may arise as audit dates and timestamps columns may not be recorded accurately by the source application.This happens because the CDC process has to run queries continually on the source Oracle database and tables to check for changes. It puts stress on the system and increases the overhead on the server.This obviously causes restrictions as it is not suitable on many occasions, especially where data in tables is deleted frequently. Records that are deleted cannot be identified since they are no longer in the table.This is a frequently used method for replication that works for a fair amount of use cases but it does have the following disadvantages: These timestamps note the date and time when a record was inserted or updated so that the changes can be replicated to the target. Oracle CDC using TimestampsĬhanged records can be replicated by using audit timestamps. ![]() CDC with Oracle can be achieved by using either timestamps or triggers. ![]() Depending on your use case, each type may present its own pros and cons. Oracle Replication with CDC can be done in a few different ways. What are the Types of Oracle Replication with CDC By only applying changes, you can avoid the consequences of replicating entire databases or tables, the main consequence being that the process can be time-consuming, expensive, and cause performance degradation. This method eliminates the need to always copy or extract an entire database or even entire tables. Using CDC allows only data changes to be replicated to the destination database or data warehouse. ![]() Although real-time CDC is generally the desired end state, this could also be done at specific time intervals set by a user. With Oracle, implementing a CDC process allows for monitoring data that is inserted, updated, and deleted so that these changes can be reflected in the destination. Something not possible before when using a batch-based approach to extracting and loading data into big data platforms. By using CDC, real-time data replication can be achieved and unlock real-time analytics use cases that many of these platforms excel at. Data warehouse destinations may include Snowflake, SQL Server, Azure Synapse, Redshift S3, Kafta, Postgres, or Google BigQuery. Using CDC allows for the easy extraction and transportation of relational data from one or more databases into a data warehouse for analysis. These changes are then replicated to a target database so that the changes are made available to other systems, applications, or individuals. Oracle CDC, or Oracle Change Data Capture, is a technology that efficiently identifies data that has been added, updated, or removed from an Oracle database. ![]()
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