Re: How to reproduce serialization failure for a read only transaction.

From: Florian Pflug <fgp(at)phlo(dot)org>
To: Jim Nasby <jim(at)nasby(dot)net>
Cc: AK <alkuzo(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: How to reproduce serialization failure for a read only transaction.
Date: 2014-01-07 17:18:52
Message-ID: 2EF4D8F7-4973-446C-915A-71D2C97E58F9@phlo.org
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On Jan7, 2014, at 00:38 , Jim Nasby <jim(at)nasby(dot)net> wrote:
> This email and the previous one are an awesome bit of information,
> can we add it to the docs somehow? Even if it's just dumping the
> emails into a wiki page and referencing it?

Most of what I wrote there can be found in README-SSE, I think,
under "Apparent Serial Order of Execution", "Heap locking" and
"Index AM implementations".

I guess it'd be nice if we explained these things in the docs
somewhere, though I'm not sure what level of detail would be
appropriate. Maybe a good compromise would be to explain dependency
graphs, but skip over the different kinds of dependencies (ww, rw, wr).
Instead we could say that whenever a transaction *does see* another
transaction's modifications it must appear after that transaction in any
serial schedule, and whenever a transaction *might see* another
transaction's modifications but doesn't due to begin/commit ordering
it must appear before that transaction.

best regards,
Florian Pflug

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