Re: Block-level CRC checks

Alvaro Herrera <alvherre@commandprompt.com> writes:

> Alvaro Herrera wrote:
>
>> The "other hint bits" are:
>> 
>> - LP_DEAD as used by the various callers of ItemIdMarkDead.
>> - PD_PAGE_FULL
>> - BTPageOpaque->btpo_flags and btpo_cycleid
>> 
>> All of them are changed with only SetBufferCommitInfoNeedsSave being
>> called afterwards.
>
> I think we could get away with WAL-logging LP_DEAD via ItemIdMarkDead
> similar to what is done to SetHintBits in the posted patch, and cope
> with the rest by marking the page with the invalid checksum; they are
> not so frequent anyway so the reliability loss is low.

If PD_PAGE_FULL is set and that causes the crc to be set to the invalid sum
will we ever get another chance to set it?

--  Gregory Stark EnterpriseDB          http://www.enterprisedb.com Ask me about EnterpriseDB's RemoteDBA services!