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Updates README and protobuf descriptor

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README.md
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decoderbufs [![License](https://img.shields.io/badge/license-MIT-brightgreen.svg?maxAge=2592000)](https://opensource.org/licenses/MIT)
=========== [![Version](https://img.shields.io/badge/version-0.1.0-brightgreen.svg?maxAge=2592000)]()
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A PostgreSQL logical decoder output plugin to deliver data as Protocol Buffers # Postgres Decoderbufs
# decoderbufs A PostgreSQL logical decoder output plugin to deliver data as [Protocol Buffers](https://developers.google.com/protocol-buffers), adapted for Debezium
Version: 0.1.0 ## Thanks to
- The original [Decoderbufs Project](https://github.com/xstevens/decoderbufs) on which this is based
- [The PostgreSQL Team](https://postgresql.org) for adding [logical decoding](http://www.postgresql.org/docs/9.4/static/logicaldecoding.html) support
**decoderbufs** is a PostgreSQL logical decoder output plugin to deliver data as Protocol Buffers. ## Dependencies
This code depends on the following libraries and requires them for compilation:
**decoderbufs** is released under the MIT license (See LICENSE file). * [PostgreSQL](http://www.postgresql.org) 9.6+
* [Protobuf-c](https://github.com/protobuf-c/protobuf-c) 1.1+ - used for data serialization
* [PostGIS](http://www.postgis.net/) 2.1+ - used for Postgres geometric types support
**Shoutouts:** ## Building
- [The PostgreSQL Team](https://postgresql.org) for adding [logical decoding](http://www.postgresql.org/docs/9.4/static/logicaldecoding.html) support. This is a immensely useful feature.
- [Michael Paquier](https://github.com/michaelpq) for his [decoder_raw](https://github.com/michaelpq/pg_plugins/tree/master/decoder_raw)
project and blog posts as a guide to teach myself how to write a PostgreSQL logical decoder output plugin.
- [Martin Kleppmann](https://github.com/ept) for making me aware that PostgreSQL was working on logical decoding.
- [Magnus Edenhill](https://github.com/edenhill) for letting me know that protobuf-c existed and just in general for writing librdkafka.
### Version Compatability To build you will need to install PostgreSQL (for pg_config), PostgreSQL server development packages, protobuf-c for the
This code is built with the following assumptions. You may get mixed results if you deviate from these versions. Protocol Buffer support and some PostGIS development packages
* [PostgreSQL](http://www.postgresql.org) 9.4+ ### Debian
* [Protocol Buffers](https://developers.google.com/protocol-buffers) 2.6.1
* [protobuf-c](https://github.com/protobuf-c/protobuf-c) 1.1.0
* [PostGIS](http://postgis.net) 2.1.x
### Requirements # Core build utilities
* PostgreSQL apt-get update && apt-get install -f -y software-properties-common build-essential pkg-config git postgresql-server-dev-9.6
* PostGIS
* Protocol Buffers
* protobuf-c
### Building
To build you will need to install PostgreSQL (for pg_config) and PostgreSQL server development packages. On Debian
based distributions you can usually do something like this:
apt-get install -y postgresql postgresql-server-dev-9.4
You will also need to make sure that protobuf-c and it's header files have been installed. See their Github # PostGIS dependency
page for further details. apt-get install -f -y libproj-dev liblwgeom-dev
# Protobuf-c dependency (requires a non-stable Debian repo)
add-apt-repository "deb http://ftp.debian.org/debian testing main contrib" && apt-get update
apt-get install -y libprotobuf-c-dev=1.2.1-1+b1
The above are taken from the Debezium [docker images](https://github.com/debezium/docker-images).
### Other Linux distributions
You just need to make sure the above software packages (_or some flavour thereof_) are installed for your distro.
Note that the last step from the above sequence is only required for Debian to be able to install `libprotobuf-c-dev:1.2.1`
If you have all of the prerequisites installed you should be able to just: If you have all of the prerequisites installed you should be able to just:
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And restart PostgreSQL. And restart PostgreSQL.
### Usage ## Usage
-- can use SQL for demo purposes -- can use SQL for demo purposes
select * from pg_create_logical_replication_slot('decoderbufs_demo', 'decoderbufs'); select * from pg_create_logical_replication_slot('decoderbufs_demo', 'decoderbufs');
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If you're performing an UPDATE/DELETE on your table and you don't see results for those operations from logical decoding, make sure you have set [REPLICA IDENTITY](http://www.postgresql.org/docs/9.4/static/sql-altertable.html#SQL-CREATETABLE-REPLICA-IDENTITY) appropriately for your use case. If you're performing an UPDATE/DELETE on your table and you don't see results for those operations from logical decoding, make sure you have set [REPLICA IDENTITY](http://www.postgresql.org/docs/9.4/static/sql-altertable.html#SQL-CREATETABLE-REPLICA-IDENTITY) appropriately for your use case.
For consuming the binary format, I have implemented a custom PostgreSQL logical replication client that publishes to Apache Kafka. I'm hoping to clean that up a bit and open source the project. The binary format will be consumed by the Debezium Postgres Connector.
### Type Mappings ## Type Mappings
The following table shows how current PostgreSQL type OIDs are mapped to which decoderbuf fields: The following table shows how current PostgreSQL type OIDs are mapped to which decoderbuf fields:
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| PostGIS geometry | datum_point | | PostGIS geometry | datum_point |
| PostGIS geography | datum_point | | PostGIS geography | datum_point |
### Support ## Support
File bug reports, feature requests and questions using
[GitHub Issues](https://github.com/xstevens/decoderbufs/issues)
### Notes
This approach is the one we wanted when we first started kicking around ideas for how to replicate our Postgres DBs in near-realtime. It should provide much better
resiliency in the face of network outages and unplanned downtime than a push mechanism (like using pg_kafka with a trigger) would.
The PostgreSQL docs are pretty good and are definitely worth a read.
**NOT ALL OID TYPES ARE SUPPORTED CURRENTLY**. I really want to iterate this point. There are lots of OIDs in Postgres. Right now I'm translating the ones that I see used a lot, but it is by no means comprehensive. I hope to update this project to support most if not all types at some point.
File bug reports and feature requests using [Debezium's JIRA](https://issues.jboss.org/browse/DBZ) and the
[postgresql-connector](https://issues.jboss.org/browse/DBZ/component/12323543) component

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proto/pg_logicaldec.proto
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package decoderbufs; package decoderbufs;
option java_package="decoderbufs.proto"; option java_package="io.debezium.connector.postgresql.proto";
option java_outer_classname = "PgldProtos"; option java_outer_classname = "PgProto";
option optimize_for = SPEED; option optimize_for = SPEED;
enum Op { enum Op {