Re: 16-bit page checksums for 9.2

On Fri, Jan 6, 2012 at 3:47 PM, Simon Riggs <simon@2ndquadrant.com> wrote:
> Since we ignore hints during HS anyway,

No, we don't.  We need to ignore visibility map bits, but we need not
and do not ignore HEAP_XMIN_COMMITTED, HEAP_XMAX_COMMITTED, etc.

> not setting them seems OK if
> checksums defined. Or we can recommend that you don't use checksums on
> a standby. Whichever fits.
>
> Writing pages during recovery doesn't need WAL. If we crash, we replay
> using the already generated WAL.

Which is all fine, except when you start making changes that are not
WAL-logged.  Then, you have the same torn page problem that exists
when you it in normal running.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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