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| author | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2010-02-03 09:47:19 +0000 |
|---|---|---|
| committer | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2010-02-03 09:47:19 +0000 |
| commit | 808969d0e7ac2d2fdbd915c6a6ac9ec68b6f63f9 (patch) | |
| tree | 0215738e25ef02df0eedee365a6a38ca57f7df37 /doc/src | |
| parent | 47c5b8f5588da67a95dca8cb14b2bc1b7f291e15 (diff) | |
| download | postgresql-808969d0e7ac2d2fdbd915c6a6ac9ec68b6f63f9.tar.gz postgresql-808969d0e7ac2d2fdbd915c6a6ac9ec68b6f63f9.zip | |
Add a message type header to the CopyData messages sent from primary
to standby in streaming replication. While we only have one message type
at the moment, adding a message type header makes this easier to extend.
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/protocol.sgml | 61 |
1 files changed, 57 insertions, 4 deletions
diff --git a/doc/src/sgml/protocol.sgml b/doc/src/sgml/protocol.sgml index 54e03998ff9..845e4181307 100644 --- a/doc/src/sgml/protocol.sgml +++ b/doc/src/sgml/protocol.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/protocol.sgml,v 1.77 2010/01/15 09:18:59 heikki Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/protocol.sgml,v 1.78 2010/02/03 09:47:19 heikki Exp $ --> <chapter id="protocol"> <title>Frontend/Backend Protocol</title> @@ -4179,12 +4179,65 @@ The commands accepted in walsender mode are: already been recycled. On success, server responds with a CopyOutResponse message, and backend starts to stream WAL as CopyData messages. + The payload in CopyData message consists of the following format. </para> <para> - The payload in each CopyData message consists of an XLogRecPtr, - indicating the starting point of the WAL in the message, immediately - followed by the WAL data itself. + <variablelist> + <varlistentry> + <term> + XLogData (B) + </term> + <listitem> + <para> + <variablelist> + <varlistentry> + <term> + Byte1('w') + </term> + <listitem> + <para> + Identifies the message as WAL data. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + Int32 + </term> + <listitem> + <para> + The log file number of the LSN, indicating the starting point of + the WAL in the message. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + Int32 + </term> + <listitem> + <para> + The byte offset of the LSN, indicating the starting point of + the WAL in the message. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + Byte<replaceable>n</replaceable> + </term> + <listitem> + <para> + Data that forms part of WAL data stream. + </para> + </listitem> + </varlistentry> + </variablelist> + </para> + </listitem> + </varlistentry> + </variablelist> </para> <para> A single WAL record is never split across two CopyData messages. When |