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Re: MDEV-10035 DBUG_ASSERT on CREATE VIEW v1 AS SELECT * FROM t1 FOR UPDATE

 

Hi, Oleksandr!

On May 16, Oleksandr Byelkin wrote:
> On 16.05.2016 06:00, Alexander Barkov wrote:
> > Hi Sanja, Sergei,
> >
> > Sanja, you asked me to review a patch for MDEV-10035:
> >
> > revision-id: 4ffe2295e78538dde93df078421726f0c5a7d2a2 
> > (mariadb-10.2.0-29-g4ffe229)
> > parent(s): b79944950e5e5db40cf7ad49061edf5f105512c4
> > committer: Oleksandr Byelkin
> > timestamp: 2016-05-15 15:25:33 +0200
> > message:
> >
> > I earlier also proposed the same idea to disallow FOR UPDATE,
> > and even created a patch disallowing this in the parser
> > syntactically (see attached).
> >
> > But Sergei worried that we should not do it this way and proposed some 
> > other solutions. Please see Sergei's comments in:
> >
> > MDEV-10063 VIEWs and subqueries with FOR UPDATE
> >
> > Sergei, are you still in doubts?

Yes :) Out of all approaches, I think, I'd prefer to issue a warning
like "Clause FOR UPDATE" won't work unless you specify TEMPTABLE
algorithm. Making it an error in the strict mode, as usual.

> Just now this parameter for VIEWs effectively (and silently) ignored. So 
> error IMHO is better.

It will break existing application where users have FOR UPDATE in the
view definition. But, probably, there won't be many?

But also this patch goes directly against the work that Bar is doing
now. This patch adds new manual syntax checks into the code, while Bar
is trying to have the grammar to allow only syntaxically corect queries.

Regards,
Sergei
Chief Architect MariaDB
and security@xxxxxxxxxxx


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