Re: Block-level CRC checks

On Mon, Dec 15, 2008 at 11:29 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> "Jonah H. Harris" <jonah.harris@gmail.com> writes:
>> On Mon, Dec 15, 2008 at 10:13 AM, Bruce Momjian <bruce@momjian.us> wrote:
>>> Feature freeze is not the time to be looking for new ideas.  I suggest
>>> we save this for 8.5.
>
>> Well, we may not need a new idea.
>
> We don't really have an acceptable solution for the conflict with hint
> bit behavior.  The shutdown issue is minor, agreed, but that's not the
> stumbling block.

Agreed on the shutdown issue.  But, didn't this patch address the hint
bit setting as discussed?  After performing a cursory look at the
patch, it appears that hint-bit changes are detected and a WAL entry
is written on buffer flush if hint bits had been changed.  I don't see
anything wrong with this in theory.  Am I missing something?

Now, in the case where hint bits have been updated and a WAL record is
required because the buffer is being flushed, requiring the WAL to be
flushed up to that point may be a killer on performance.  Has anyone
tested it?

-- 
Jonah H. Harris, Senior DBA
myYearbook.com