Pipeline Modes

In case of RDBMS Sources, you can select from the following Pipeline Modes to define how Hevo must read your data from the database.

  • Table: In this mode, your tables are read individually at a fixed frequency. Use this mode to fetch data from multiple tables in your database, while maintaining control over the ingestion for every table individually. You can fetch data using different query modes.

  • Custom SQL: Use this mode if you are looking to fetch data in a different structure than how it is stored in your Source tables. Custom SQL mode allows you to fetch data using a custom query at a fixed frequency.

  • BinLog: This mode is applicable for MySQL Sources. In this mode, data is read using MySQL’s BinLog. This mode is useful when you are looking to replicate the complete database, as is, to the Destination. This mode is very efficient in replicating but leaves you with less control and manageability over data ingestion. Read BinLog Replication and BinLog Alerts.

  • Logical Replication: This mode is applicable for the Postgres Source. In this mode, data will be replicated using Postgres Write Ahead Log (WAL) set at a logical level (available on Postgres version 9.4 and above). This mode is useful when you are looking to replicate the complete database as it is. Please note that Hevo will create a new Replication Slot for the Pipeline which may lead to higher disk consumption in your Postgres Database. Read about the instructions to set up the WAL for Logical Replication here.

  • Redo log: This mode is applicable for the Oracle Source. This involves using Oracle Logminer to incrementally ingest the data from oracle redo logs. This is the recommended way to do data replication in Oracle. You can read more about Logminer here. Read about the instructions to set up the Redo Log here

BinLog Replication

After a historical load of the initial state of the MySQL database, the BinLog is continuously streamed. The first time the data is ingested, the table definitions are directly read from the schema and not the BinLog. Post that all of the schema updates are read from the BinLog, for near real-time replication at scale. This approach supports both deletions and table alterations leading to exactly one-to-one replication. It doesn’t require locks or affect the performance of the database. It is also very consistent with the stream processing paradigm allowing near real-time performance.

BinLog Alerts

Where Pipeline mode is BinLog, if the BinLog retention period is set as less than 24 hours, (and Hevo has sufficient permissions to read the BinLog configurations), Hevo displays a one-time warning to increase the retention period. “BinLog retention is set to hours. We recommend having BinLog retention of at least 24 hours to avoid disruption in replication due to spikes.”

Refer to MySQL’s replication reference guide to know about the options available for replication and binary logging. The mysql_rds_set_configuration page provides information on BinLog retention in RDS instances.

Last updated on 19 Oct 2020