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From Юрий <jury.gerzhedow...@gmail.com>
Subject Re: delete is too slow, sometimes even causes OOM
Date Thu, 19 Nov 2020 13:57:17 GMT
Frank,

Tiket [1] has been resolved. Try to use LAZY flag for your DML query on the
new nightly build.

[1] https://issues.apache.org/jira/browse/IGNITE-9182

пн, 9 нояб. 2020 г. в 19:28, Denis Magda <dmagda@apache.org>:

> Frank,
>
> The ticket doesn't suggest the lazy flag as a workaround. The flag is
> supposed to be used to address the performance issue.
>
> How about a workaround on your application side while you're waiting for
> this improvement?
>
>    - Query all the records for a deletion - "SELECT record_primary_key
>    WHERE delete_condition"
>    - Delete the records using the key-value API -
>    cache.removeAll(all_primary_keys).
>
> -
> Denis
>
>
> On Mon, Nov 9, 2020 at 8:20 AM frank li <frankli22568@gmail.com> wrote:
>
> > I enforced  a lazy flag in DELETE code for tesing, but it is stil running
> > very slow. I mean that "Lazy" flag cannot solve the problem of running
> too
> > slow.
> >
> > On 2020/11/06 09:50:15, Юрий <jury.gerzhedowich@gmail.com> wrote:
> > > Hi Frank!
> > >
> > > There is an old ticket [1] - We will try to prioritize it to finish
> > before
> > > the end of the year it should prevent OOM for most cases.
> > >
> > > [1] https://issues.apache.org/jira/browse/IGNITE-9182
> > >
> > > вт, 3 нояб. 2020 г. в 18:53, frank li <frankli22568@gmail.com>:
> > >
> > > > Current code logic for DELETE is as follows:
> > > > if WHERE clause contains a condition as "key=xxx", it uses fastUpdate
> > > > which remove the related item directly.
> > > >
> > > > else
> > > >     do select for update;
> > > >     for each row, call closure code "RMV" to remove it.
> > > >
> > > > 1. As "executeSelectForDml" get _KEY and _VAL columns for all
> condidate
> > > > rows, it often causes OOM when there are a lot of data  to delete.
> Why
> > do
> > > > we verify "val" during remove operation?
> > > >
> > > > 2. After selection,  why don't we just remove it with cache.remove as
> > > > fastUpdate does?
> > > >
> > > >
> > > >
> > >
> > > --
> > > Живи с улыбкой! :D
> > >
> >
>


-- 
Живи с улыбкой! :D

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