Re: our checks for read-only queries are not great - Mailing list pgsql-hackers

From Robert Haas
Subject Re: our checks for read-only queries are not great
Date
Msg-id CA+TgmoZRWLmv4jwz6+peq-N-a87ddFouERxGTHGBW-QU_xb2nA@mail.gmail.com
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In response to Re: our checks for read-only queries are not great  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: our checks for read-only queries are not great  (Robert Haas <robertmhaas@gmail.com>)
Re: our checks for read-only queries are not great  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Thu, Jan 9, 2020 at 3:07 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
> > Maybe the SQL standard has something to say about this?
>
> [ pokes around ... ]  Yeah, it does, and I'd say it's pretty clearly
> in agreement with what Peter did, so far as DML ops go.  For instance,
> this bit from SQL99's description of DELETE:
>
>          1) If the access mode of the current SQL-transaction or the access
>             mode of the branch of the current SQL-transaction at the current
>             SQL-connection is read-only, and T is not a temporary table,
>             then an exception condition is raised: invalid transaction state
>             - read-only SQL-transaction.
>
> UPDATE and INSERT say the same.  (I didn't look at later spec versions,
> since Peter's 2003 commit was probably based on SQL99.)

OK. That's good to know.

> You could argue about exactly how to extend that to non-spec
> utility commands, but for the most part allowing them seems
> to make sense if DML is allowed.

But I think we allow them on all tables, not just temp tables, so I
don't think I understand this argument.

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



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