Overcoming Pitfalls of Postgres Logical Decoding

At PeerDB, we are building a fast and simple way to replicate data from Postgres to data warehouses like Snowflake, ClickHouse etc. and queues such as Kafka, Redpanda etc. We implement Postgres Change Data Capture (CDC) to reliably replicate changes from Postgres to other data stores. Postgres Logical Decoding is a building block of Postgres CDC. It enables users to stream changes on Postgres as a sequence of logical operations like INSERTs, UPDATEs, and DELETEs. Logical Decoding has evolved quite a bit in the past few years in Postgres. However, there are a few quirks that users need to overcome. In this blog, we will summarize common issues and learnings from over 20 customers replicating more than 300 TB of data per month with logical decoding. A logical replication slot captures changes in the Postgres Write-Ahead Log (WAL) and streams them in a human-readable format to the client. A common issue with logical decoding is unexpected replication slot growth, which can risk filling up

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• Hieu Tran