Re: Freezing is not WAL-logged

Alvaro Herrera wrote:
> Tom Lane wrote:
>> "Heikki Linnakangas" <heikki(at)enterprisedb(dot)com> writes:
>>> I just noticed that freezing a tuple (in vacuumlazy.c) is not
>>> WAL-logged.
>> The theory is that this doesn't matter because the tuple is committed
>> either way ... it's equivalent to a hint-bit update which we don'ton
>> WAL-log either.
>
> Also it'd be hugely expensive to log each freeze operation. The
> alternative would be to log a VACUUM FREEZE, but that has the potential
> to cause enormous recovery runtime.

Freezing isn't very common, and a single WAL record per page would be
enough. I can write the patch.

It does have the potential to increase recovery times, but I don't think
we can just cross our fingers and hope that no crash happens after
freezing some tuples.

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