Why aren't master and slave DBs binary identical?

Started by Josh Berkusover 15 years ago4 messages
#1Josh Berkus
josh@agliodbs.com

Hackers,

We've noticed that checksums and file sizes for the master database, and
slave database, even after all transactions have been cleared, are not
identical. Why is that?

--
-- Josh Berkus
PostgreSQL Experts Inc.
http://www.pgexperts.com

#2Andres Freund
andres@anarazel.de
In reply to: Josh Berkus (#1)
Re: Why aren't master and slave DBs binary identical?

Hi,

On Friday 18 June 2010 00:22:00 Josh Berkus wrote:

We've noticed that checksums and file sizes for the master database, and
slave database, even after all transactions have been cleared, are not
identical. Why is that?

Non Wal-Logged action like visibility bits.

Andres

#3Tom Lane
tgl@sss.pgh.pa.us
In reply to: Andres Freund (#2)
Re: Why aren't master and slave DBs binary identical?

Andres Freund <andres@anarazel.de> writes:

On Friday 18 June 2010 00:22:00 Josh Berkus wrote:

We've noticed that checksums and file sizes for the master database, and
slave database, even after all transactions have been cleared, are not
identical. Why is that?

Non Wal-Logged action like visibility bits.

That wouldn't affect file sizes though. Could we have some specifics?

regards, tom lane

#4Andrew Dunstan
andrew@dunslane.net
In reply to: Tom Lane (#3)
Re: Why aren't master and slave DBs binary identical?

Tom Lane wrote:

Andres Freund <andres@anarazel.de> writes:

On Friday 18 June 2010 00:22:00 Josh Berkus wrote:

We've noticed that checksums and file sizes for the master database, and
slave database, even after all transactions have been cleared, are not
identical. Why is that?

Non Wal-Logged action like visibility bits.

That wouldn't affect file sizes though. Could we have some specifics?

I have not noticed different file sizes, only checksums.

cheers

andrew