Re: Repeatable read and serializable transactions see data committed after tx start - Mailing list pgsql-hackers

From Robert Haas
Subject Re: Repeatable read and serializable transactions see data committed after tx start
Date
Msg-id CA+TgmoZAj2e0irM7DtrtKam751BVvLmJqi8=pSO=59R3-5WwEQ@mail.gmail.com
Whole thread Raw
In response to Re: Repeatable read and serializable transactions see data committed after tx start  (Álvaro Hernández Tortosa <aht@8Kdata.com>)
List pgsql-hackers
On Wed, Nov 5, 2014 at 7:17 PM, Álvaro Hernández Tortosa <aht@8kdata.com> wrote:
>>>      Given a transaction started with "BEGIN.... (REPEATABLE READ |
>>> SERIALIZABLE)", if a concurrent session commits some data before *any*
>>> query
>>> within the first transaction, that committed data is seen by the
>>> transaction. This is not what I'd expect.
>>
>> I think the problem is with your expectation, not the behavior.
>
>     But my expectation is derived from the documentation:
>
> "The Repeatable Read isolation level only sees data committed before the
> transaction began;"

Yes, that's inaccurate.  We should fix it.

(But we should not change the behavior, because I'm pretty sure that
the villagers would show up with pitchforks when various
currently-harmless scenarios caused massive database bloat.)

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



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