From: | Peter Geoghegan <pg(at)bowt(dot)ie> |
---|---|
To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
Cc: | Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru>, Haribabu Kommi <kommi(dot)haribabu(at)gmail(dot)com>, Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Pluggable storage |
Date: | 2017-10-13 17:59:51 |
Message-ID: | CAH2-WzkN1+xYZG5Z-RqNO6q6aL71FFjh8xEa1FAVFTqyFk9kWQ@mail.gmail.com |
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On Thu, Oct 12, 2017 at 2:23 PM, Robert Haas <robertmhaas(at)gmail(dot)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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