Re: For SELECT statement (just a reading one, no 'FOR UPDATE'), isCOMMIT or ROLLBACK preferred? - Mailing list pgsql-general

From Luca Ferrari
Subject Re: For SELECT statement (just a reading one, no 'FOR UPDATE'), isCOMMIT or ROLLBACK preferred?
Date
Msg-id CAKoxK+4AQWAvwoXR17tWBBmW3TL7kha5gY35i3dCBOMnnyQpLQ@mail.gmail.com
Whole thread Raw
In response to Re: For SELECT statement (just a reading one, no 'FOR UPDATE'), isCOMMIT or ROLLBACK preferred?  (David Wall <d.wall@computer.org>)
List pgsql-general
On Sun, Aug 25, 2019 at 10:12 PM David Wall <d.wall@computer.org> wrote:
> The main issue is that if
> we do a SELECT and get a ResultSet that has no rows, if we do a commit
> or a rollback, it seems reasonable that these are identical as no
> changes were made.  My inclination is to do a Connection.commit() on the
> connection because it wasn't in error or anything even if no rows were
> found, but wondered if a Connection.rollback() has any difference
> (positive/negative) in such a scenario.

Quite frankly I would redesign your application workflow. Sounds like
you are building a framework to issue queries, and I suggest you to
clearly mark transactions only when needed because, disregarding
performances, it does not make much sense to commit/rollback on a
"data quantity" discrimintation. At least, as far as you described it.

Moreover, as Tom pointed out, there could be a SELECT against a
function (that could return nothing at all) with side effects. How are
you going to discriminate such case?

Luca



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