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Posted to dev@ignite.apache.org by Vladimir Ozerov <vo...@gridgain.com> on 2017/11/28 07:33:46 UTC
Re: FOR UPDATE support in SELECT clause
Hi Denis,
"FOR UPDATE" is not supported at the moment. We will add it's support for
transactional case [1]. In non-transactional case it would behave in the
same way as normal SELECT.
[1] https://issues.apache.org/jira/browse/IGNITE-6937
On Thu, Oct 19, 2017 at 3:21 AM, Denis Magda <dm...@apache.org> wrote:
> Vladimir, Alex P.,
>
> In addition to that please review INSERT, UPDATE, DELETE, MERGE commands
> syntax. Are all the parameters (DIRECT, SORTED, etc.) supported by Ignite
> and if, yes, then how? I’m doubt that Ignite fully supports H2 syntax:
> https://apacheignite-sql.readme.io/v2.1/docs/dml
>
> —
> Denis
>
> > On Oct 18, 2017, at 2:02 PM, Denis Magda <dm...@apache.org> wrote:
> >
> > Vladimir, Igniters,
> >
> > I’m editing the new version of our SELECT page [1] that initially
> consisted of the content fully copied from H2.
> >
> > For instance, there we had the following statement that’s not true for
> Ignite: "If FOR UPDATE is specified, the tables are locked for writing.
> When using MVCC, only the selected rows are locked as in an UPDATE
> statement. In this case, aggregate, GROUP BY, DISTINCTqueries or joins are
> not allowed in this case."
> >
> > How do we process FOR UPDATE parameter in Ignite right now? Please do a
> proof-read of the page at all confirming the rest data applies for Ignite.
> >
> > [1] https://apacheignite-sql.readme.io/v2.1/docs/select
> >
> > —
> > Denis
>
>
Re: FOR UPDATE support in SELECT clause
Posted by Vladimir Ozerov <vo...@gridgain.com>.
In this case you lock rows, but there are not subsequent operation which
will use this lock. FOR UPDATE only makes sense as a part of transaction.
On Tue, Nov 28, 2017 at 4:56 PM, Dmitriy Setrakyan <ds...@apache.org>
wrote:
> On Tue, Nov 28, 2017 at 12:34 AM, Vladimir Ozerov <vo...@gridgain.com>
> wrote:
>
> > I do not see any use case for this. Why would you want to do this?
> >
>
> Atomic cache supports locking to my knowledge. The use case would be
> identical in SQL use case - to lock a row. Why not?
>
Re: FOR UPDATE support in SELECT clause
Posted by Dmitriy Setrakyan <ds...@apache.org>.
On Tue, Nov 28, 2017 at 12:34 AM, Vladimir Ozerov <vo...@gridgain.com>
wrote:
> I do not see any use case for this. Why would you want to do this?
>
Atomic cache supports locking to my knowledge. The use case would be
identical in SQL use case - to lock a row. Why not?
Re: FOR UPDATE support in SELECT clause
Posted by Vladimir Ozerov <vo...@gridgain.com>.
I do not see any use case for this. Why would you want to do this?
On Tue, Nov 28, 2017 at 11:18 AM, Dmitriy Setrakyan <ds...@apache.org>
wrote:
> On Mon, Nov 27, 2017 at 11:33 PM, Vladimir Ozerov <vo...@gridgain.com>
> wrote:
>
> > Hi Denis,
> >
> > "FOR UPDATE" is not supported at the moment. We will add it's support for
> > transactional case [1]. In non-transactional case it would behave in the
> > same way as normal SELECT.
> >
>
> Why only for transactional cases? Why can't we lock for non-transactional
> cases as well?
>
Re: FOR UPDATE support in SELECT clause
Posted by Dmitriy Setrakyan <ds...@apache.org>.
On Mon, Nov 27, 2017 at 11:33 PM, Vladimir Ozerov <vo...@gridgain.com>
wrote:
> Hi Denis,
>
> "FOR UPDATE" is not supported at the moment. We will add it's support for
> transactional case [1]. In non-transactional case it would behave in the
> same way as normal SELECT.
>
Why only for transactional cases? Why can't we lock for non-transactional
cases as well?