Horton

Re: 16-bit page checksums for 9.2

Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>

View thread
From: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
To: Simon Riggs <simon@2ndQuadrant.com>
Cc: Bruce Momjian <bruce@momjian.us>, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2012-02-06T10:44:27Z
Lists: pgsql-hackers 
On 06.02.2012 11:25, Simon Riggs wrote:
> On Mon, Feb 6, 2012 at 10:02 AM, Heikki Linnakangas
> <heikki.linnakangas@enterprisedb.com>  wrote:
>> Good idea. However, the followup idea to that discussion was to not only
>> avoid the I/O needed to mark tuples as frozen, but to avoid xid wraparound
>> altogether, by allowing clog to grow indefinitely. You do want to freeze at
>> some point of course, to truncate the clog, but it would be nice to not have
>> a hard limit. The way to do that is to store an xid "epoch" in the page
>> header, so that Xids are effectively 64-bits wide, even though the xid
>> fields on the tuple header are only 32-bits wide. That does require a new
>> field in the page header.
>
> We wouldn't need to do that would we?

Huh? Do you mean that we wouldn't need to implement that feature?

-- 
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com