Re: Documenting serializable vs snapshot isolation levels - Mailing list pgsql-hackers

From Robert Haas
Subject Re: Documenting serializable vs snapshot isolation levels
Date
Msg-id 603c8f070812300758v1495fa17g68623e94fd6c6630@mail.gmail.com
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In response to Re: Documenting serializable vs snapshot isolation levels  ("Kevin Grittner" <Kevin.Grittner@wicourts.gov>)
Responses Re: Documenting serializable vs snapshot isolation levels  ("Kevin Grittner" <Kevin.Grittner@wicourts.gov>)
List pgsql-hackers
> The effects are different, I think, in that there isn't a
> serialization failure in some conflict cases where you would get one
> with actual updates.  I found a paper on how to use updates to provide
> serializable transactions in a snapshot database, and I'd have to
> review closely to see how that difference affected the technique.  I
> had been thinking that the WAL generation and bloat issues made the
> technique pretty iffy, but if SELECT FOR UPDATE suffices in place of
> most of the proposed updates, it just might be feasible.

In fact, I think SELECT FOR SHARE is enough.  That will give you
better concurrency, since it will block only updates and not
concurrent read transactions.

...Robert


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