Re: Page Checksums + Double Writes

Kevin Grittner <kevin.grittner@wicourts.gov>

From: "Kevin Grittner" <Kevin.Grittner@wicourts.gov>

To: "Jim Nasby" <jim@nasby.net>

Cc: "Simon Riggs" <simon@2ndquadrant.com>, <alvherre@commandprompt.com>,<david@fetter.org>, "Jeff Janes" <jeff.janes@gmail.com>, "Robert Haas" <robertmhaas@gmail.com>, <pgsql-hackers@postgresql.org>, <tgl@sss.pgh.pa.us>

Date: 2012-01-04T20:02:01Z

Lists: pgsql-hackers

Jim Nasby <jim@nasby.net> wrote:

> Here's output from our largest OLTP system... not sure exactly how
> to interpret it, so I'm just providing the raw data. This spans
> almost exactly 1 month.

Those number wind up meaning that 18% of the 256-byte blocks (1024
transactions each) were all commits.  Yikes.  That pretty much
shoots down Robert's idea of summarized CLOG data, I think.

-Kevin