On 28.01.2012 15:49, Simon Riggs wrote:
> On Fri, Jan 27, 2012 at 9:07 PM, Dan Scales<scales@vmware.com> wrote:
>
>> Also, I missed this before: don't you want to add the checksum calculation (PageSetVerificationInfo) to mdextend()
(orpreferably smgrextend()) as well? Otherwise, you won't be checksumming a bunch of the new pages.
>
> You don't need to checksum the extend because no data is written at
> that point.
That's not correct. smgrextend writes a block of data just like
smgrwrite does. When a relation is extended by the buffer manager, it
calls smgrextend with an all-zeros block, but not all callers do that.
See rewriteheap.c and nbtsort.c for counter-examples.
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com