Re: [HACKERS] Pluggable storage - Mailing list pgsql-hackers

From Peter Geoghegan
Subject Re: [HACKERS] Pluggable storage
Date
Msg-id CAH2-WzkN1+xYZG5Z-RqNO6q6aL71FFjh8xEa1FAVFTqyFk9kWQ@mail.gmail.com
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In response to Re: [HACKERS] Pluggable storage  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: [HACKERS] Pluggable storage
List pgsql-hackers
On Thu, Oct 12, 2017 at 2:23 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Thu, Oct 12, 2017 at 4:38 PM, Alexander Korotkov
>> However I imply that alternative storage would share our "MVCC model".  So,
>> it
>> should share our transactional model including transactions,
>> subtransactions, snapshots etc.
>> Therefore, if alternative storage is transactional, then in particular it
>> should be able to fetch tuple with
>> given TID according to given snapshot.  However, how it's implemented
>> internally is
>> a black box for us.  Thus, we don't insist that tuple should have different
>> TID after update;
>> we don't insist there is any analogue of HOT; we don't insist alternative
>> storage needs vacuum
>> (or if even it needs vacuum, it might be performed in completely different
>> way) and so on.
>
> Fully agreed.

If we implement that interface, where does that leave EvalPlanQual()?
Do those semantics have to be preserved?

-- 
Peter Geoghegan


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