Logical Decoding Plugins
Logical decoding provides the ability to stream modifications made via SQL to external consumers.
To be able to use logical decoding you need to install a plugin into postgresql to transform the WAL internal representation to a format the client can use.
JSON format plugins
wal2json
https://github.com/eulerto/wal2json
JSON output plugin for changeset extraction
"change": [
{
"kind": "insert",
"schema": "public",
"table": "table_with_pk",
"columnnames": ["a", "b", "c"],
"columntypes": ["int4", "varchar", "timestamp"],
"columnvalues": [1, "Backup and Restore", "2015-08-27 16:46:35.818038"]
}]
decoding-json
This plugin receives the changes from WAL and decodes them to JSON.
{"type":"transaction.begin","xid":"2010561","committed":"2015-04-22 19:23:35.714443+00"}
{"type":"table","name":"abc","change":"INSERT","data":{"a":6,"b":7,"c":42}}
{"type":"table","name":"abc","change":"UPDATE","key":{"a":6,"b":7},"data":{"a":6,"b":7,"c":13}}
decoder_json
Uses libjansson for json generation rather than native postgresql code
jsoncdc
Written in rust
wal2mongo
Translates changesets into a format consumable directly by MongoDB
Protobuf Format Plugins
decoderbufs
decoderbufs is a PostgreSQL logical decoder output plugin to deliver data as Protocol Buffers.
postgres-decoderbufs
A fork of xstevens/decoderbufs for use as a debezium connector
Avro Format Plugins
Bottled Water
Streams into Kafka. No longer supported.
SQL Format Plugins
decoder_raw
This output plugin for logical replication generates raw queries based on the logical changes it finds. Those queries can be consumed as they are by any remote source.
Miscellaneous Plugins
test_decoding
contrib/test_decoding is example code for a logical decoding output plugin. It describes itself as "doesn't do anything especially useful, but can serve as a starting point for developing your own decoder".
People have written code to parse the output from this plugin, but that doesn't make it a good idea:
- https://github.com/davecramer/LogicalDecode - java
- https://github.com/lisael/pylogicaldecoding - python
- https://github.com/kibae/pg-logical-replication - node.js
osm-logical
Toy code for use with openstreetmaps. Looks to be based on test_decoding.
pglogical
pglogical is a logical replication system, implemented as a postgresql extension
transicator
transicator reads from a single logical decoding connection and replicates change out to many (thousands) of intermittently connected clients via a REST API
