Re: Doc patch for Logical Replication Message Formats (PG14)

From: Brar Piening <brar(at)gmx(dot)de>
To: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
Cc: PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: Doc patch for Logical Replication Message Formats (PG14)
Date: 2021-06-21 10:43:26
Message-ID: 6d64f7aa-efb4-a50c-c96b-2c33ba6dcd26@gmx.de
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Amit Kapila wrote:
> On Mon, Jun 21, 2021 at 12:26 PM Brar Piening <brar(at)gmx(dot)de> wrote:
>> Hello Hackers,
>> while amending Npgsql to account for the Logical Streaming Replication
>> Protocol changes in PostgreSQL 14 I stumbled upon two documentation
>> inaccuracies in the Logical Replication Message Formats documentation
>> (https://www.postgresql.org/docs/devel/protocol-logicalrep-message-formats.html)
>> that have been introduced (or rather omitted) with the recent changes to
>> allow pgoutput to send logical decoding messages
>> (https://github.com/postgres/postgres/commit/ac4645c0157fc5fcef0af8ff571512aa284a2cec)
>> and to allow logical replication to transfer data in binary format
>> (https://github.com/postgres/postgres/commit/9de77b5453130242654ff0b30a551c9c862ed661)
>>
>>
>> 1. The content of the logical decoding message in the 'Message' message
>> is prefixed with a length field (Int32) which isn't documented yet.
>> See
>> https://github.com/postgres/postgres/blob/69a58bfe4ab05567a8fab8bdce7f3095ed06b99c/src/backend/replication/logical/proto.c#L388
>> 2. The TupleData may now contain the byte 'b' as indicator for binary
>> data which isn't documented yet. See
>> https://github.com/postgres/postgres/blob/69a58bfe4ab05567a8fab8bdce7f3095ed06b99c/src/include/replication/logicalproto.h#L83
>> and
>> https://github.com/postgres/postgres/blob/69a58bfe4ab05567a8fab8bdce7f3095ed06b99c/src/backend/replication/logical/proto.c#L558.
>>
>> The attached documentation patch fixes both.
>>
> Yeah, I think these should be fixed and your patch looks good to me in
> that regard.
>
After looking at the docs once again I have another minor amendment (new
patch attached).

Attachment Content-Type Size
protocol-logicalrep-message-formats-pg14-fix_v2.patch text/plain 1.2 KB

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