Horton

Re: [PATCH 10/16] Introduce the concept that wal has a 'origin' node

Simon Riggs <simon@2ndquadrant.com>

View thread
From: Simon Riggs <simon@2ndQuadrant.com>
To: Kevin Grittner <Kevin.Grittner@wicourts.gov>
Cc: Andres Freund <andres@2ndquadrant.com>, pgsql-hackers@postgresql.org, Robert Haas <robertmhaas@gmail.com>, Daniel Farina <daniel@heroku.com>, Tom Lane <tgl@sss.pgh.pa.us>
Date: 2012-06-19T22:02:06Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Don't waste the last segment of each 4GB logical log file.

  2. Stamp HEAD as 9.3devel.

  3. Wake WALSender to reduce data loss at failover for async commit.

  4. Make the visibility map crash-safe.

On 20 June 2012 04:31, Kevin Grittner <Kevin.Grittner@wicourts.gov> wrote:

> I've done a lot of MM replication,
> and so far have not had to use a topology which allowed loops.

The proposal is to use WAL to generate the logical change stream. That
has been shown in testing to be around x4 faster than having a
separate change stream, which must also be WAL logged (as Jan noted).

If we use WAL in this way, multi-master implies that the data will
*always* be in a loop. So in any configuration we must be able to tell
difference between changes made by one node and another.

-- 
 Simon Riggs                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services