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Posted to dev@ignite.apache.org by Valentin Kulichenko <va...@gmail.com> on 2016/02/04 06:17:03 UTC
Transformers in SCAN queries
Igniters,
I keep getting requests from our users to add optional transformers to SCAN
queries. This will allow to iterate through cache, but do not transfer
whole key-value pairs across networks (e.g., get only keys). The feature
looks useful and I created a ticket [1].
I am struggling with the design now. The problem is that I wanted to extend
existing ScanQuery object for this, but this seems to be impossible because
it already extends Query<Cache.Entry<K, V>> and thus can iterate only
through entries.
The only option I see now is to create a separate query type, copy-paste
everything from ScanQuery and add *mandatory* transformer. Something like
this:
ScanTransformQuery<K, V, R> extends Query<R> {
IgniteBiPredicate<K, V> filter;
IgniteClosure<Cache.Entry<K, V>, R> transformer;
int part;
...
}
Thoughts? Does anyone has other ideas?
[1] https://issues.apache.org/jira/browse/IGNITE-2546
-Val
Re: Transformers in SCAN queries
Posted by Semyon Boikov <sb...@gridgain.com>.
I think scan query implementation can be more complex than just sending
closures to all nodes. e.g. it should handle topology changes. IMO it is
not good idea to use compute instead of queries.
On Thu, Feb 4, 2016 at 10:55 AM, Dmitriy Setrakyan <ds...@apache.org>
wrote:
> On Wed, Feb 3, 2016 at 10:28 PM, Valentin Kulichenko <
> valentin.kulichenko@gmail.com> wrote:
>
> > Dmitry,
> >
> > The main difference in my view is that you lose pagination when sending
> > results from servers to client. What if one wants to iterate through all
> > entries in cache?
> >
>
> I see. Perhaps we should fix the pagination for compute instead of adding
> transformers for queries?
>
>
> >
> > On Wed, Feb 3, 2016 at 9:47 PM, Dmitriy Setrakyan <dsetrakyan@apache.org
> >
> > wrote:
> >
> > > Valentin,
> > >
> > > Wouldn’t the same effect be achieved by broadcasting a closure to the
> > > cluster and executing scan-query on every node locally?
> > >
> > > D.
> > >
> > > On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko <
> > > valentin.kulichenko@gmail.com> wrote:
> > >
> > > > Igniters,
> > > >
> > > > I keep getting requests from our users to add optional transformers
> to
> > > SCAN
> > > > queries. This will allow to iterate through cache, but do not
> transfer
> > > > whole key-value pairs across networks (e.g., get only keys). The
> > feature
> > > > looks useful and I created a ticket [1].
> > > >
> > > > I am struggling with the design now. The problem is that I wanted to
> > > extend
> > > > existing ScanQuery object for this, but this seems to be impossible
> > > because
> > > > it already extends Query<Cache.Entry<K, V>> and thus can iterate only
> > > > through entries.
> > > >
> > > > The only option I see now is to create a separate query type,
> > copy-paste
> > > > everything from ScanQuery and add *mandatory* transformer. Something
> > like
> > > > this:
> > > >
> > > > ScanTransformQuery<K, V, R> extends Query<R> {
> > > > IgniteBiPredicate<K, V> filter;
> > > > IgniteClosure<Cache.Entry<K, V>, R> transformer;
> > > > int part;
> > > > ...
> > > > }
> > > >
> > > > Thoughts? Does anyone has other ideas?
> > > >
> > > > [1] https://issues.apache.org/jira/browse/IGNITE-2546
> > > >
> > > > -Val
> > > >
> > >
> >
>
Re: Transformers in SCAN queries
Posted by Dmitriy Setrakyan <ds...@apache.org>.
On Wed, Feb 3, 2016 at 10:28 PM, Valentin Kulichenko <
valentin.kulichenko@gmail.com> wrote:
> Dmitry,
>
> The main difference in my view is that you lose pagination when sending
> results from servers to client. What if one wants to iterate through all
> entries in cache?
>
I see. Perhaps we should fix the pagination for compute instead of adding
transformers for queries?
>
> On Wed, Feb 3, 2016 at 9:47 PM, Dmitriy Setrakyan <ds...@apache.org>
> wrote:
>
> > Valentin,
> >
> > Wouldn’t the same effect be achieved by broadcasting a closure to the
> > cluster and executing scan-query on every node locally?
> >
> > D.
> >
> > On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko <
> > valentin.kulichenko@gmail.com> wrote:
> >
> > > Igniters,
> > >
> > > I keep getting requests from our users to add optional transformers to
> > SCAN
> > > queries. This will allow to iterate through cache, but do not transfer
> > > whole key-value pairs across networks (e.g., get only keys). The
> feature
> > > looks useful and I created a ticket [1].
> > >
> > > I am struggling with the design now. The problem is that I wanted to
> > extend
> > > existing ScanQuery object for this, but this seems to be impossible
> > because
> > > it already extends Query<Cache.Entry<K, V>> and thus can iterate only
> > > through entries.
> > >
> > > The only option I see now is to create a separate query type,
> copy-paste
> > > everything from ScanQuery and add *mandatory* transformer. Something
> like
> > > this:
> > >
> > > ScanTransformQuery<K, V, R> extends Query<R> {
> > > IgniteBiPredicate<K, V> filter;
> > > IgniteClosure<Cache.Entry<K, V>, R> transformer;
> > > int part;
> > > ...
> > > }
> > >
> > > Thoughts? Does anyone has other ideas?
> > >
> > > [1] https://issues.apache.org/jira/browse/IGNITE-2546
> > >
> > > -Val
> > >
> >
>
Re: Transformers in SCAN queries
Posted by Dmitriy Setrakyan <ds...@apache.org>.
On Thu, Feb 11, 2016 at 6:18 AM, Andrey Gura <ag...@gridgain.com> wrote:
> Despite of trasformer makes little sense for the SqlFieldsQuery I don't see
> any reason for throwing of UnsupportedOperationException.
> I think it is stange limitation from user standpoint.
>
I think either supporting it or not supporting looks strange for
SqlFieldsQuery. I suggested to throw the exception only to simplify the
development - simply one less thing to worry about.
>
> On Thu, Feb 11, 2016 at 6:01 AM, Valentin Kulichenko <
> valentin.kulichenko@gmail.com> wrote:
>
> > I changed the description in the ticket. If anyone has comments about the
> > implementation details, feel free to add them there.
> >
> > -Val
> >
> > On Wed, Feb 10, 2016 at 2:30 PM, Dmitriy Setrakyan <
> dsetrakyan@apache.org>
> > wrote:
> >
> > > I like the new method on IgniteCache API:
> > >
> > > <R> QueryCursor<R> query(Query<E> qry, Transformer<E, R> transformer);
> > >
> > > I do agree that it makes little sense for the SqlFieldsQuery, but we
> can
> > > simply throw an unsupported exception here. For all other queries it
> does
> > > make sense.
> > >
> > > Val, can you put together all the thoughts expressed in this thread
> into
> > a
> > > ticket?
> > >
> > > D.
> > >
> > > On Thu, Feb 4, 2016 at 4:14 PM, Andrey Gura <ag...@gridgain.com>
> wrote:
> > >
> > > > Val,
> > > >
> > > > From my point of view, special query class that allows transforming
> is
> > > > confusing. Two points about it:
> > > >
> > > > 1. ScanTransformQuery will duplicate ScanQuery code with all
> drawbacks
> > > that
> > > > we have. Moreover, any fix for ScanQuery should be repeated for
> > > > ScanTransformQuery. It will lead to bugs. DRY.
> > > >
> > > > 2. If some users want to do transformations for SqlQuery we will
> > > introduce
> > > > SqlTransformQuery. Right? At this point see previous item.
> > > >
> > > > Transformation logic is some kind of strategy. IMHO, the most
> > convenient
> > > > API should get transformation logic as some function provided by
> user.
> > > >
> > > > On Thu, Feb 4, 2016 at 11:05 PM, Valentin Kulichenko <
> > > > valentin.kulichenko@gmail.com> wrote:
> > > >
> > > > > Agree with Sergi. Mixing SQL with Java code transformers is
> > confusing.
> > > In
> > > > > rare case when it's really required, user can implement a custom
> > > > function.
> > > > >
> > > > > I copy-pasted the API to the ticket [1]. Please provide any
> > additional
> > > > > comments there.
> > > > >
> > > > > [1] https://issues.apache.org/jira/browse/IGNITE-2546
> > > > >
> > > > > -Val
> > > > >
> > > > > On Thu, Feb 4, 2016 at 10:08 AM, Andrey Gura <ag...@gridgain.com>
> > > wrote:
> > > > >
> > > > > > Sergi,
> > > > > >
> > > > > >
> > > > > > > What you are going to transform remotely here?
> > > > > >
> > > > > >
> > > > > > I'm not going. I believe :)
> > > > > >
> > > > > > Just hypothetical use case: You have one SqlFieldsQuery but
> > different
> > > > > > requirements for returned values. For one case you have to return
> > > some
> > > > > > string fields as is and for another case you have to trim string
> to
> > > 32
> > > > > > characters. Of course you still can trim strings locally but
> > > > transformers
> > > > > > allow you do it remotely.
> > > > > >
> > > > > > Anyway, this solution can be usefull for rest query types.
> > > > > >
> > > > > > On Thu, Feb 4, 2016 at 8:54 PM, Sergi Vladykin <
> > > > sergi.vladykin@gmail.com
> > > > > >
> > > > > > wrote:
> > > > > >
> > > > > > > The whole point of Transformer is to do remote transform, how
> > will
> > > > this
> > > > > > > work with SqlFieldsQuery? What you are going to transform
> > remotely
> > > > > here?
> > > > > > I
> > > > > > > believe all the transformations must happen at SQL level here.
> > > > > > >
> > > > > > > Sergi
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 2016-02-04 20:10 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
> > > > > > >
> > > > > > > > SqlQuery, TextQuery and SpiQuery are similar to ScanQuery
> > because
> > > > all
> > > > > > of
> > > > > > > > them also defined as Query<Cache.Entry<>>.
> > > > > > > >
> > > > > > > > It can be usefull to have one query SqlQuery that can return
> > > > > different
> > > > > > > > result that will be produced from cache entry by transformer.
> > > > > > > >
> > > > > > > > Actually only SqlFieldsQuery has different definition. So
> > > > > transformers
> > > > > > > can
> > > > > > > > be applied to any type of query (including SqlFieldsQuery, I
> > > > > believe).
> > > > > > > >
> > > > > > > > On Thu, Feb 4, 2016 at 7:42 PM, Sergi Vladykin <
> > > > > > sergi.vladykin@gmail.com
> > > > > > > >
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > I don't like the idea of having additional method
> > > *query(Query<E>
> > > > > > qry,
> > > > > > > > > Transformer<E, R> transfomer); *because I don't see how
> these
> > > > > > > > transformers
> > > > > > > > > will work for example with SQL, but this API makes you
> think
> > > that
> > > > > > > > > transformers are supported for all the query types.
> > > > > > > > >
> > > > > > > > > Sergi
> > > > > > > > >
> > > > > > > > > 2016-02-04 16:46 GMT+03:00 Andrey Gura <agura@gridgain.com
> >:
> > > > > > > > >
> > > > > > > > > > Val,
> > > > > > > > > >
> > > > > > > > > > can we introduce new method into IgnteCache API?
> > > > > > > > > >
> > > > > > > > > > Now we have method: public <R> QueryCursor<R>
> > query(Query<R>
> > > > > qry);
> > > > > > > > > >
> > > > > > > > > > New method will be something like this: <R>
> QueryCursor<R>
> > > > > > > > query(Query<E>
> > > > > > > > > > qry, Transformer<E, R> transfomer);
> > > > > > > > > >
> > > > > > > > > > It allows provide transformers for all query types and
> > > chnages
> > > > > will
> > > > > > > be
> > > > > > > > > > related only with query cursor functionality.
> > > > > > > > > >
> > > > > > > > > > Will it work?
> > > > > > > > > >
> > > > > > > > > > On Thu, Feb 4, 2016 at 11:13 AM, Andrey Kornev <
> > > > > > > > andrewkornev@hotmail.com
> > > > > > > > > >
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Another perhaps bigger problem with running queries
> > > > (including
> > > > > > scan
> > > > > > > > > > > queries) using closures was discussed at length on the
> > @dev
> > > > not
> > > > > > so
> > > > > > > > long
> > > > > > > > > > > ago. It has to do with partitions migration due to
> > cluster
> > > > > > topology
> > > > > > > > > > changes
> > > > > > > > > > > which may result in the query returning incomplete
> > result.
> > > > And
> > > > > > > while
> > > > > > > > it
> > > > > > > > > > is
> > > > > > > > > > > possible to solve this problem for the scan queries by
> > > using
> > > > > some
> > > > > > > > > clever
> > > > > > > > > > > tricks, all bets are off with the SQL queries.Andrey
> > > > > > > > > > > _____________________________
> > > > > > > > > > > From: Valentin Kulichenko <
> valentin.kulichenko@gmail.com
> > >
> > > > > > > > > > > Sent: Thursday, February 4, 2016 6:29 AM
> > > > > > > > > > > Subject: Re: Transformers in SCAN queries
> > > > > > > > > > > To: <de...@ignite.apache.org>
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Dmitry,
> > > > > > > > > > >
> > > > > > > > > > > The main difference in my view is that you lose
> > pagination
> > > > > when
> > > > > > > > > sending
> > > > > > > > > > > results from servers to client. What if one wants to
> > > iterate
> > > > > > > through
> > > > > > > > > all
> > > > > > > > > > > entries in cache?
> > > > > > > > > > >
> > > > > > > > > > > On Wed, Feb 3, 2016 at 9:47 PM, Dmitriy Setrakyan <
> > > > > > > > > > dsetrakyan@apache.org>
> > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Valentin,
> > > > > > > > > > > >
> > > > > > > > > > > > Wouldn’t the same effect be achieved by
> broadcasting a
> > > > > closure
> > > > > > > to
> > > > > > > > > the
> > > > > > > > > > > > cluster and executing scan-query on every node
> > locally?
> > > > > > > > > > > >
> > > > > > > > > > > > D.
> > > > > > > > > > > >
> > > > > > > > > > > > On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko
> <
> > > > > > > > > > > > valentin.kulichenko@gmail.com> wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Igniters,
> > > > > > > > > > > > >
> > > > > > > > > > > > > I keep getting requests from our users to add
> > optional
> > > > > > > > > transformers
> > > > > > > > > > to
> > > > > > > > > > > > SCAN
> > > > > > > > > > > > > queries. This will allow to iterate through cache,
> > but
> > > > do
> > > > > > not
> > > > > > > > > > transfer
> > > > > > > > > > > > > whole key-value pairs across networks (e.g., get
> > only
> > > > > keys).
> > > > > > > The
> > > > > > > > > > > feature
> > > > > > > > > > > > > looks useful and I created a ticket [1].
> > > > > > > > > > > > >
> > > > > > > > > > > > > I am struggling with the design now. The problem
> is
> > > > that I
> > > > > > > > wanted
> > > > > > > > > to
> > > > > > > > > > > > extend
> > > > > > > > > > > > > existing ScanQuery object for this, but this seems
> > to
> > > be
> > > > > > > > > impossible
> > > > > > > > > > > > because
> > > > > > > > > > > > > it already extends Query<Cache.Entry<K, V>> and
> thus
> > > can
> > > > > > > iterate
> > > > > > > > > > only
> > > > > > > > > > > > > through entries.
> > > > > > > > > > > > >
> > > > > > > > > > > > > The only option I see now is to create a separate
> > > query
> > > > > > type,
> > > > > > > > > > > copy-paste
> > > > > > > > > > > > > everything from ScanQuery and add *mandatory*
> > > > transformer.
> > > > > > > > > Something
> > > > > > > > > > > like
> > > > > > > > > > > > > this:
> > > > > > > > > > > > >
> > > > > > > > > > > > > ScanTransformQuery<K, V, R> extends Query<R> {
> > > > > > > > > > > > > IgniteBiPredicate<K, V> filter;
> > > > > > > > > > > > > IgniteClosure<Cache.Entry<K, V>, R>
> transformer;
> > > > > > > > > > > > > int part;
> > > > > > > > > > > > > ...
> > > > > > > > > > > > > }
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thoughts? Does anyone has other ideas?
> > > > > > > > > > > > >
> > > > > > > > > > > > > [1]
> > > > https://issues.apache.org/jira/browse/IGNITE-2546
> > > > > > > > > > > > >
> > > > > > > > > > > > > -Val
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > --
> > > > > > > > > > Andrey Gura
> > > > > > > > > > GridGain Systems, Inc.
> > > > > > > > > > www.gridgain.com
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > --
> > > > > > > > Andrey Gura
> > > > > > > > GridGain Systems, Inc.
> > > > > > > > www.gridgain.com
> > > > > > > >
> > > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > --
> > > > > > Andrey Gura
> > > > > > GridGain Systems, Inc.
> > > > > > www.gridgain.com
> > > > > >
> > > > >
> > > >
> > > >
> > > >
> > > > --
> > > > Andrey Gura
> > > > GridGain Systems, Inc.
> > > > www.gridgain.com
> > > >
> > >
> >
>
>
>
> --
> Andrey Gura
> GridGain Systems, Inc.
> www.gridgain.com
>
Re: Transformers in SCAN queries
Posted by Andrey Gura <ag...@gridgain.com>.
Despite of trasformer makes little sense for the SqlFieldsQuery I don't see
any reason for throwing of UnsupportedOperationException.
I think it is stange limitation from user standpoint.
On Thu, Feb 11, 2016 at 6:01 AM, Valentin Kulichenko <
valentin.kulichenko@gmail.com> wrote:
> I changed the description in the ticket. If anyone has comments about the
> implementation details, feel free to add them there.
>
> -Val
>
> On Wed, Feb 10, 2016 at 2:30 PM, Dmitriy Setrakyan <ds...@apache.org>
> wrote:
>
> > I like the new method on IgniteCache API:
> >
> > <R> QueryCursor<R> query(Query<E> qry, Transformer<E, R> transformer);
> >
> > I do agree that it makes little sense for the SqlFieldsQuery, but we can
> > simply throw an unsupported exception here. For all other queries it does
> > make sense.
> >
> > Val, can you put together all the thoughts expressed in this thread into
> a
> > ticket?
> >
> > D.
> >
> > On Thu, Feb 4, 2016 at 4:14 PM, Andrey Gura <ag...@gridgain.com> wrote:
> >
> > > Val,
> > >
> > > From my point of view, special query class that allows transforming is
> > > confusing. Two points about it:
> > >
> > > 1. ScanTransformQuery will duplicate ScanQuery code with all drawbacks
> > that
> > > we have. Moreover, any fix for ScanQuery should be repeated for
> > > ScanTransformQuery. It will lead to bugs. DRY.
> > >
> > > 2. If some users want to do transformations for SqlQuery we will
> > introduce
> > > SqlTransformQuery. Right? At this point see previous item.
> > >
> > > Transformation logic is some kind of strategy. IMHO, the most
> convenient
> > > API should get transformation logic as some function provided by user.
> > >
> > > On Thu, Feb 4, 2016 at 11:05 PM, Valentin Kulichenko <
> > > valentin.kulichenko@gmail.com> wrote:
> > >
> > > > Agree with Sergi. Mixing SQL with Java code transformers is
> confusing.
> > In
> > > > rare case when it's really required, user can implement a custom
> > > function.
> > > >
> > > > I copy-pasted the API to the ticket [1]. Please provide any
> additional
> > > > comments there.
> > > >
> > > > [1] https://issues.apache.org/jira/browse/IGNITE-2546
> > > >
> > > > -Val
> > > >
> > > > On Thu, Feb 4, 2016 at 10:08 AM, Andrey Gura <ag...@gridgain.com>
> > wrote:
> > > >
> > > > > Sergi,
> > > > >
> > > > >
> > > > > > What you are going to transform remotely here?
> > > > >
> > > > >
> > > > > I'm not going. I believe :)
> > > > >
> > > > > Just hypothetical use case: You have one SqlFieldsQuery but
> different
> > > > > requirements for returned values. For one case you have to return
> > some
> > > > > string fields as is and for another case you have to trim string to
> > 32
> > > > > characters. Of course you still can trim strings locally but
> > > transformers
> > > > > allow you do it remotely.
> > > > >
> > > > > Anyway, this solution can be usefull for rest query types.
> > > > >
> > > > > On Thu, Feb 4, 2016 at 8:54 PM, Sergi Vladykin <
> > > sergi.vladykin@gmail.com
> > > > >
> > > > > wrote:
> > > > >
> > > > > > The whole point of Transformer is to do remote transform, how
> will
> > > this
> > > > > > work with SqlFieldsQuery? What you are going to transform
> remotely
> > > > here?
> > > > > I
> > > > > > believe all the transformations must happen at SQL level here.
> > > > > >
> > > > > > Sergi
> > > > > >
> > > > > >
> > > > > >
> > > > > > 2016-02-04 20:10 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
> > > > > >
> > > > > > > SqlQuery, TextQuery and SpiQuery are similar to ScanQuery
> because
> > > all
> > > > > of
> > > > > > > them also defined as Query<Cache.Entry<>>.
> > > > > > >
> > > > > > > It can be usefull to have one query SqlQuery that can return
> > > > different
> > > > > > > result that will be produced from cache entry by transformer.
> > > > > > >
> > > > > > > Actually only SqlFieldsQuery has different definition. So
> > > > transformers
> > > > > > can
> > > > > > > be applied to any type of query (including SqlFieldsQuery, I
> > > > believe).
> > > > > > >
> > > > > > > On Thu, Feb 4, 2016 at 7:42 PM, Sergi Vladykin <
> > > > > sergi.vladykin@gmail.com
> > > > > > >
> > > > > > > wrote:
> > > > > > >
> > > > > > > > I don't like the idea of having additional method
> > *query(Query<E>
> > > > > qry,
> > > > > > > > Transformer<E, R> transfomer); *because I don't see how these
> > > > > > > transformers
> > > > > > > > will work for example with SQL, but this API makes you think
> > that
> > > > > > > > transformers are supported for all the query types.
> > > > > > > >
> > > > > > > > Sergi
> > > > > > > >
> > > > > > > > 2016-02-04 16:46 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
> > > > > > > >
> > > > > > > > > Val,
> > > > > > > > >
> > > > > > > > > can we introduce new method into IgnteCache API?
> > > > > > > > >
> > > > > > > > > Now we have method: public <R> QueryCursor<R>
> query(Query<R>
> > > > qry);
> > > > > > > > >
> > > > > > > > > New method will be something like this: <R> QueryCursor<R>
> > > > > > > query(Query<E>
> > > > > > > > > qry, Transformer<E, R> transfomer);
> > > > > > > > >
> > > > > > > > > It allows provide transformers for all query types and
> > chnages
> > > > will
> > > > > > be
> > > > > > > > > related only with query cursor functionality.
> > > > > > > > >
> > > > > > > > > Will it work?
> > > > > > > > >
> > > > > > > > > On Thu, Feb 4, 2016 at 11:13 AM, Andrey Kornev <
> > > > > > > andrewkornev@hotmail.com
> > > > > > > > >
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Another perhaps bigger problem with running queries
> > > (including
> > > > > scan
> > > > > > > > > > queries) using closures was discussed at length on the
> @dev
> > > not
> > > > > so
> > > > > > > long
> > > > > > > > > > ago. It has to do with partitions migration due to
> cluster
> > > > > topology
> > > > > > > > > changes
> > > > > > > > > > which may result in the query returning incomplete
> result.
> > > And
> > > > > > while
> > > > > > > it
> > > > > > > > > is
> > > > > > > > > > possible to solve this problem for the scan queries by
> > using
> > > > some
> > > > > > > > clever
> > > > > > > > > > tricks, all bets are off with the SQL queries.Andrey
> > > > > > > > > > _____________________________
> > > > > > > > > > From: Valentin Kulichenko <valentin.kulichenko@gmail.com
> >
> > > > > > > > > > Sent: Thursday, February 4, 2016 6:29 AM
> > > > > > > > > > Subject: Re: Transformers in SCAN queries
> > > > > > > > > > To: <de...@ignite.apache.org>
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Dmitry,
> > > > > > > > > >
> > > > > > > > > > The main difference in my view is that you lose
> pagination
> > > > when
> > > > > > > > sending
> > > > > > > > > > results from servers to client. What if one wants to
> > iterate
> > > > > > through
> > > > > > > > all
> > > > > > > > > > entries in cache?
> > > > > > > > > >
> > > > > > > > > > On Wed, Feb 3, 2016 at 9:47 PM, Dmitriy Setrakyan <
> > > > > > > > > dsetrakyan@apache.org>
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Valentin,
> > > > > > > > > > >
> > > > > > > > > > > Wouldn’t the same effect be achieved by broadcasting a
> > > > closure
> > > > > > to
> > > > > > > > the
> > > > > > > > > > > cluster and executing scan-query on every node
> locally?
> > > > > > > > > > >
> > > > > > > > > > > D.
> > > > > > > > > > >
> > > > > > > > > > > On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko <
> > > > > > > > > > > valentin.kulichenko@gmail.com> wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Igniters,
> > > > > > > > > > > >
> > > > > > > > > > > > I keep getting requests from our users to add
> optional
> > > > > > > > transformers
> > > > > > > > > to
> > > > > > > > > > > SCAN
> > > > > > > > > > > > queries. This will allow to iterate through cache,
> but
> > > do
> > > > > not
> > > > > > > > > transfer
> > > > > > > > > > > > whole key-value pairs across networks (e.g., get
> only
> > > > keys).
> > > > > > The
> > > > > > > > > > feature
> > > > > > > > > > > > looks useful and I created a ticket [1].
> > > > > > > > > > > >
> > > > > > > > > > > > I am struggling with the design now. The problem is
> > > that I
> > > > > > > wanted
> > > > > > > > to
> > > > > > > > > > > extend
> > > > > > > > > > > > existing ScanQuery object for this, but this seems
> to
> > be
> > > > > > > > impossible
> > > > > > > > > > > because
> > > > > > > > > > > > it already extends Query<Cache.Entry<K, V>> and thus
> > can
> > > > > > iterate
> > > > > > > > > only
> > > > > > > > > > > > through entries.
> > > > > > > > > > > >
> > > > > > > > > > > > The only option I see now is to create a separate
> > query
> > > > > type,
> > > > > > > > > > copy-paste
> > > > > > > > > > > > everything from ScanQuery and add *mandatory*
> > > transformer.
> > > > > > > > Something
> > > > > > > > > > like
> > > > > > > > > > > > this:
> > > > > > > > > > > >
> > > > > > > > > > > > ScanTransformQuery<K, V, R> extends Query<R> {
> > > > > > > > > > > > IgniteBiPredicate<K, V> filter;
> > > > > > > > > > > > IgniteClosure<Cache.Entry<K, V>, R> transformer;
> > > > > > > > > > > > int part;
> > > > > > > > > > > > ...
> > > > > > > > > > > > }
> > > > > > > > > > > >
> > > > > > > > > > > > Thoughts? Does anyone has other ideas?
> > > > > > > > > > > >
> > > > > > > > > > > > [1]
> > > https://issues.apache.org/jira/browse/IGNITE-2546
> > > > > > > > > > > >
> > > > > > > > > > > > -Val
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > --
> > > > > > > > > Andrey Gura
> > > > > > > > > GridGain Systems, Inc.
> > > > > > > > > www.gridgain.com
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > --
> > > > > > > Andrey Gura
> > > > > > > GridGain Systems, Inc.
> > > > > > > www.gridgain.com
> > > > > > >
> > > > > >
> > > > >
> > > > >
> > > > >
> > > > > --
> > > > > Andrey Gura
> > > > > GridGain Systems, Inc.
> > > > > www.gridgain.com
> > > > >
> > > >
> > >
> > >
> > >
> > > --
> > > Andrey Gura
> > > GridGain Systems, Inc.
> > > www.gridgain.com
> > >
> >
>
--
Andrey Gura
GridGain Systems, Inc.
www.gridgain.com
Re: Transformers in SCAN queries
Posted by Valentin Kulichenko <va...@gmail.com>.
I changed the description in the ticket. If anyone has comments about the
implementation details, feel free to add them there.
-Val
On Wed, Feb 10, 2016 at 2:30 PM, Dmitriy Setrakyan <ds...@apache.org>
wrote:
> I like the new method on IgniteCache API:
>
> <R> QueryCursor<R> query(Query<E> qry, Transformer<E, R> transformer);
>
> I do agree that it makes little sense for the SqlFieldsQuery, but we can
> simply throw an unsupported exception here. For all other queries it does
> make sense.
>
> Val, can you put together all the thoughts expressed in this thread into a
> ticket?
>
> D.
>
> On Thu, Feb 4, 2016 at 4:14 PM, Andrey Gura <ag...@gridgain.com> wrote:
>
> > Val,
> >
> > From my point of view, special query class that allows transforming is
> > confusing. Two points about it:
> >
> > 1. ScanTransformQuery will duplicate ScanQuery code with all drawbacks
> that
> > we have. Moreover, any fix for ScanQuery should be repeated for
> > ScanTransformQuery. It will lead to bugs. DRY.
> >
> > 2. If some users want to do transformations for SqlQuery we will
> introduce
> > SqlTransformQuery. Right? At this point see previous item.
> >
> > Transformation logic is some kind of strategy. IMHO, the most convenient
> > API should get transformation logic as some function provided by user.
> >
> > On Thu, Feb 4, 2016 at 11:05 PM, Valentin Kulichenko <
> > valentin.kulichenko@gmail.com> wrote:
> >
> > > Agree with Sergi. Mixing SQL with Java code transformers is confusing.
> In
> > > rare case when it's really required, user can implement a custom
> > function.
> > >
> > > I copy-pasted the API to the ticket [1]. Please provide any additional
> > > comments there.
> > >
> > > [1] https://issues.apache.org/jira/browse/IGNITE-2546
> > >
> > > -Val
> > >
> > > On Thu, Feb 4, 2016 at 10:08 AM, Andrey Gura <ag...@gridgain.com>
> wrote:
> > >
> > > > Sergi,
> > > >
> > > >
> > > > > What you are going to transform remotely here?
> > > >
> > > >
> > > > I'm not going. I believe :)
> > > >
> > > > Just hypothetical use case: You have one SqlFieldsQuery but different
> > > > requirements for returned values. For one case you have to return
> some
> > > > string fields as is and for another case you have to trim string to
> 32
> > > > characters. Of course you still can trim strings locally but
> > transformers
> > > > allow you do it remotely.
> > > >
> > > > Anyway, this solution can be usefull for rest query types.
> > > >
> > > > On Thu, Feb 4, 2016 at 8:54 PM, Sergi Vladykin <
> > sergi.vladykin@gmail.com
> > > >
> > > > wrote:
> > > >
> > > > > The whole point of Transformer is to do remote transform, how will
> > this
> > > > > work with SqlFieldsQuery? What you are going to transform remotely
> > > here?
> > > > I
> > > > > believe all the transformations must happen at SQL level here.
> > > > >
> > > > > Sergi
> > > > >
> > > > >
> > > > >
> > > > > 2016-02-04 20:10 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
> > > > >
> > > > > > SqlQuery, TextQuery and SpiQuery are similar to ScanQuery because
> > all
> > > > of
> > > > > > them also defined as Query<Cache.Entry<>>.
> > > > > >
> > > > > > It can be usefull to have one query SqlQuery that can return
> > > different
> > > > > > result that will be produced from cache entry by transformer.
> > > > > >
> > > > > > Actually only SqlFieldsQuery has different definition. So
> > > transformers
> > > > > can
> > > > > > be applied to any type of query (including SqlFieldsQuery, I
> > > believe).
> > > > > >
> > > > > > On Thu, Feb 4, 2016 at 7:42 PM, Sergi Vladykin <
> > > > sergi.vladykin@gmail.com
> > > > > >
> > > > > > wrote:
> > > > > >
> > > > > > > I don't like the idea of having additional method
> *query(Query<E>
> > > > qry,
> > > > > > > Transformer<E, R> transfomer); *because I don't see how these
> > > > > > transformers
> > > > > > > will work for example with SQL, but this API makes you think
> that
> > > > > > > transformers are supported for all the query types.
> > > > > > >
> > > > > > > Sergi
> > > > > > >
> > > > > > > 2016-02-04 16:46 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
> > > > > > >
> > > > > > > > Val,
> > > > > > > >
> > > > > > > > can we introduce new method into IgnteCache API?
> > > > > > > >
> > > > > > > > Now we have method: public <R> QueryCursor<R> query(Query<R>
> > > qry);
> > > > > > > >
> > > > > > > > New method will be something like this: <R> QueryCursor<R>
> > > > > > query(Query<E>
> > > > > > > > qry, Transformer<E, R> transfomer);
> > > > > > > >
> > > > > > > > It allows provide transformers for all query types and
> chnages
> > > will
> > > > > be
> > > > > > > > related only with query cursor functionality.
> > > > > > > >
> > > > > > > > Will it work?
> > > > > > > >
> > > > > > > > On Thu, Feb 4, 2016 at 11:13 AM, Andrey Kornev <
> > > > > > andrewkornev@hotmail.com
> > > > > > > >
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Another perhaps bigger problem with running queries
> > (including
> > > > scan
> > > > > > > > > queries) using closures was discussed at length on the @dev
> > not
> > > > so
> > > > > > long
> > > > > > > > > ago. It has to do with partitions migration due to cluster
> > > > topology
> > > > > > > > changes
> > > > > > > > > which may result in the query returning incomplete result.
> > And
> > > > > while
> > > > > > it
> > > > > > > > is
> > > > > > > > > possible to solve this problem for the scan queries by
> using
> > > some
> > > > > > > clever
> > > > > > > > > tricks, all bets are off with the SQL queries.Andrey
> > > > > > > > > _____________________________
> > > > > > > > > From: Valentin Kulichenko <va...@gmail.com>
> > > > > > > > > Sent: Thursday, February 4, 2016 6:29 AM
> > > > > > > > > Subject: Re: Transformers in SCAN queries
> > > > > > > > > To: <de...@ignite.apache.org>
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Dmitry,
> > > > > > > > >
> > > > > > > > > The main difference in my view is that you lose pagination
> > > when
> > > > > > > sending
> > > > > > > > > results from servers to client. What if one wants to
> iterate
> > > > > through
> > > > > > > all
> > > > > > > > > entries in cache?
> > > > > > > > >
> > > > > > > > > On Wed, Feb 3, 2016 at 9:47 PM, Dmitriy Setrakyan <
> > > > > > > > dsetrakyan@apache.org>
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Valentin,
> > > > > > > > > >
> > > > > > > > > > Wouldn’t the same effect be achieved by broadcasting a
> > > closure
> > > > > to
> > > > > > > the
> > > > > > > > > > cluster and executing scan-query on every node locally?
> > > > > > > > > >
> > > > > > > > > > D.
> > > > > > > > > >
> > > > > > > > > > On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko <
> > > > > > > > > > valentin.kulichenko@gmail.com> wrote:
> > > > > > > > > >
> > > > > > > > > > > Igniters,
> > > > > > > > > > >
> > > > > > > > > > > I keep getting requests from our users to add optional
> > > > > > > transformers
> > > > > > > > to
> > > > > > > > > > SCAN
> > > > > > > > > > > queries. This will allow to iterate through cache, but
> > do
> > > > not
> > > > > > > > transfer
> > > > > > > > > > > whole key-value pairs across networks (e.g., get only
> > > keys).
> > > > > The
> > > > > > > > > feature
> > > > > > > > > > > looks useful and I created a ticket [1].
> > > > > > > > > > >
> > > > > > > > > > > I am struggling with the design now. The problem is
> > that I
> > > > > > wanted
> > > > > > > to
> > > > > > > > > > extend
> > > > > > > > > > > existing ScanQuery object for this, but this seems to
> be
> > > > > > > impossible
> > > > > > > > > > because
> > > > > > > > > > > it already extends Query<Cache.Entry<K, V>> and thus
> can
> > > > > iterate
> > > > > > > > only
> > > > > > > > > > > through entries.
> > > > > > > > > > >
> > > > > > > > > > > The only option I see now is to create a separate
> query
> > > > type,
> > > > > > > > > copy-paste
> > > > > > > > > > > everything from ScanQuery and add *mandatory*
> > transformer.
> > > > > > > Something
> > > > > > > > > like
> > > > > > > > > > > this:
> > > > > > > > > > >
> > > > > > > > > > > ScanTransformQuery<K, V, R> extends Query<R> {
> > > > > > > > > > > IgniteBiPredicate<K, V> filter;
> > > > > > > > > > > IgniteClosure<Cache.Entry<K, V>, R> transformer;
> > > > > > > > > > > int part;
> > > > > > > > > > > ...
> > > > > > > > > > > }
> > > > > > > > > > >
> > > > > > > > > > > Thoughts? Does anyone has other ideas?
> > > > > > > > > > >
> > > > > > > > > > > [1]
> > https://issues.apache.org/jira/browse/IGNITE-2546
> > > > > > > > > > >
> > > > > > > > > > > -Val
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > --
> > > > > > > > Andrey Gura
> > > > > > > > GridGain Systems, Inc.
> > > > > > > > www.gridgain.com
> > > > > > > >
> > > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > --
> > > > > > Andrey Gura
> > > > > > GridGain Systems, Inc.
> > > > > > www.gridgain.com
> > > > > >
> > > > >
> > > >
> > > >
> > > >
> > > > --
> > > > Andrey Gura
> > > > GridGain Systems, Inc.
> > > > www.gridgain.com
> > > >
> > >
> >
> >
> >
> > --
> > Andrey Gura
> > GridGain Systems, Inc.
> > www.gridgain.com
> >
>
Re: Transformers in SCAN queries
Posted by Dmitriy Setrakyan <ds...@apache.org>.
I like the new method on IgniteCache API:
<R> QueryCursor<R> query(Query<E> qry, Transformer<E, R> transformer);
I do agree that it makes little sense for the SqlFieldsQuery, but we can
simply throw an unsupported exception here. For all other queries it does
make sense.
Val, can you put together all the thoughts expressed in this thread into a
ticket?
D.
On Thu, Feb 4, 2016 at 4:14 PM, Andrey Gura <ag...@gridgain.com> wrote:
> Val,
>
> From my point of view, special query class that allows transforming is
> confusing. Two points about it:
>
> 1. ScanTransformQuery will duplicate ScanQuery code with all drawbacks that
> we have. Moreover, any fix for ScanQuery should be repeated for
> ScanTransformQuery. It will lead to bugs. DRY.
>
> 2. If some users want to do transformations for SqlQuery we will introduce
> SqlTransformQuery. Right? At this point see previous item.
>
> Transformation logic is some kind of strategy. IMHO, the most convenient
> API should get transformation logic as some function provided by user.
>
> On Thu, Feb 4, 2016 at 11:05 PM, Valentin Kulichenko <
> valentin.kulichenko@gmail.com> wrote:
>
> > Agree with Sergi. Mixing SQL with Java code transformers is confusing. In
> > rare case when it's really required, user can implement a custom
> function.
> >
> > I copy-pasted the API to the ticket [1]. Please provide any additional
> > comments there.
> >
> > [1] https://issues.apache.org/jira/browse/IGNITE-2546
> >
> > -Val
> >
> > On Thu, Feb 4, 2016 at 10:08 AM, Andrey Gura <ag...@gridgain.com> wrote:
> >
> > > Sergi,
> > >
> > >
> > > > What you are going to transform remotely here?
> > >
> > >
> > > I'm not going. I believe :)
> > >
> > > Just hypothetical use case: You have one SqlFieldsQuery but different
> > > requirements for returned values. For one case you have to return some
> > > string fields as is and for another case you have to trim string to 32
> > > characters. Of course you still can trim strings locally but
> transformers
> > > allow you do it remotely.
> > >
> > > Anyway, this solution can be usefull for rest query types.
> > >
> > > On Thu, Feb 4, 2016 at 8:54 PM, Sergi Vladykin <
> sergi.vladykin@gmail.com
> > >
> > > wrote:
> > >
> > > > The whole point of Transformer is to do remote transform, how will
> this
> > > > work with SqlFieldsQuery? What you are going to transform remotely
> > here?
> > > I
> > > > believe all the transformations must happen at SQL level here.
> > > >
> > > > Sergi
> > > >
> > > >
> > > >
> > > > 2016-02-04 20:10 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
> > > >
> > > > > SqlQuery, TextQuery and SpiQuery are similar to ScanQuery because
> all
> > > of
> > > > > them also defined as Query<Cache.Entry<>>.
> > > > >
> > > > > It can be usefull to have one query SqlQuery that can return
> > different
> > > > > result that will be produced from cache entry by transformer.
> > > > >
> > > > > Actually only SqlFieldsQuery has different definition. So
> > transformers
> > > > can
> > > > > be applied to any type of query (including SqlFieldsQuery, I
> > believe).
> > > > >
> > > > > On Thu, Feb 4, 2016 at 7:42 PM, Sergi Vladykin <
> > > sergi.vladykin@gmail.com
> > > > >
> > > > > wrote:
> > > > >
> > > > > > I don't like the idea of having additional method *query(Query<E>
> > > qry,
> > > > > > Transformer<E, R> transfomer); *because I don't see how these
> > > > > transformers
> > > > > > will work for example with SQL, but this API makes you think that
> > > > > > transformers are supported for all the query types.
> > > > > >
> > > > > > Sergi
> > > > > >
> > > > > > 2016-02-04 16:46 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
> > > > > >
> > > > > > > Val,
> > > > > > >
> > > > > > > can we introduce new method into IgnteCache API?
> > > > > > >
> > > > > > > Now we have method: public <R> QueryCursor<R> query(Query<R>
> > qry);
> > > > > > >
> > > > > > > New method will be something like this: <R> QueryCursor<R>
> > > > > query(Query<E>
> > > > > > > qry, Transformer<E, R> transfomer);
> > > > > > >
> > > > > > > It allows provide transformers for all query types and chnages
> > will
> > > > be
> > > > > > > related only with query cursor functionality.
> > > > > > >
> > > > > > > Will it work?
> > > > > > >
> > > > > > > On Thu, Feb 4, 2016 at 11:13 AM, Andrey Kornev <
> > > > > andrewkornev@hotmail.com
> > > > > > >
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Another perhaps bigger problem with running queries
> (including
> > > scan
> > > > > > > > queries) using closures was discussed at length on the @dev
> not
> > > so
> > > > > long
> > > > > > > > ago. It has to do with partitions migration due to cluster
> > > topology
> > > > > > > changes
> > > > > > > > which may result in the query returning incomplete result.
> And
> > > > while
> > > > > it
> > > > > > > is
> > > > > > > > possible to solve this problem for the scan queries by using
> > some
> > > > > > clever
> > > > > > > > tricks, all bets are off with the SQL queries.Andrey
> > > > > > > > _____________________________
> > > > > > > > From: Valentin Kulichenko <va...@gmail.com>
> > > > > > > > Sent: Thursday, February 4, 2016 6:29 AM
> > > > > > > > Subject: Re: Transformers in SCAN queries
> > > > > > > > To: <de...@ignite.apache.org>
> > > > > > > >
> > > > > > > >
> > > > > > > > Dmitry,
> > > > > > > >
> > > > > > > > The main difference in my view is that you lose pagination
> > when
> > > > > > sending
> > > > > > > > results from servers to client. What if one wants to iterate
> > > > through
> > > > > > all
> > > > > > > > entries in cache?
> > > > > > > >
> > > > > > > > On Wed, Feb 3, 2016 at 9:47 PM, Dmitriy Setrakyan <
> > > > > > > dsetrakyan@apache.org>
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Valentin,
> > > > > > > > >
> > > > > > > > > Wouldn’t the same effect be achieved by broadcasting a
> > closure
> > > > to
> > > > > > the
> > > > > > > > > cluster and executing scan-query on every node locally?
> > > > > > > > >
> > > > > > > > > D.
> > > > > > > > >
> > > > > > > > > On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko <
> > > > > > > > > valentin.kulichenko@gmail.com> wrote:
> > > > > > > > >
> > > > > > > > > > Igniters,
> > > > > > > > > >
> > > > > > > > > > I keep getting requests from our users to add optional
> > > > > > transformers
> > > > > > > to
> > > > > > > > > SCAN
> > > > > > > > > > queries. This will allow to iterate through cache, but
> do
> > > not
> > > > > > > transfer
> > > > > > > > > > whole key-value pairs across networks (e.g., get only
> > keys).
> > > > The
> > > > > > > > feature
> > > > > > > > > > looks useful and I created a ticket [1].
> > > > > > > > > >
> > > > > > > > > > I am struggling with the design now. The problem is
> that I
> > > > > wanted
> > > > > > to
> > > > > > > > > extend
> > > > > > > > > > existing ScanQuery object for this, but this seems to be
> > > > > > impossible
> > > > > > > > > because
> > > > > > > > > > it already extends Query<Cache.Entry<K, V>> and thus can
> > > > iterate
> > > > > > > only
> > > > > > > > > > through entries.
> > > > > > > > > >
> > > > > > > > > > The only option I see now is to create a separate query
> > > type,
> > > > > > > > copy-paste
> > > > > > > > > > everything from ScanQuery and add *mandatory*
> transformer.
> > > > > > Something
> > > > > > > > like
> > > > > > > > > > this:
> > > > > > > > > >
> > > > > > > > > > ScanTransformQuery<K, V, R> extends Query<R> {
> > > > > > > > > > IgniteBiPredicate<K, V> filter;
> > > > > > > > > > IgniteClosure<Cache.Entry<K, V>, R> transformer;
> > > > > > > > > > int part;
> > > > > > > > > > ...
> > > > > > > > > > }
> > > > > > > > > >
> > > > > > > > > > Thoughts? Does anyone has other ideas?
> > > > > > > > > >
> > > > > > > > > > [1]
> https://issues.apache.org/jira/browse/IGNITE-2546
> > > > > > > > > >
> > > > > > > > > > -Val
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > --
> > > > > > > Andrey Gura
> > > > > > > GridGain Systems, Inc.
> > > > > > > www.gridgain.com
> > > > > > >
> > > > > >
> > > > >
> > > > >
> > > > >
> > > > > --
> > > > > Andrey Gura
> > > > > GridGain Systems, Inc.
> > > > > www.gridgain.com
> > > > >
> > > >
> > >
> > >
> > >
> > > --
> > > Andrey Gura
> > > GridGain Systems, Inc.
> > > www.gridgain.com
> > >
> >
>
>
>
> --
> Andrey Gura
> GridGain Systems, Inc.
> www.gridgain.com
>
Re: Transformers in SCAN queries
Posted by Andrey Gura <ag...@gridgain.com>.
Val,
>From my point of view, special query class that allows transforming is
confusing. Two points about it:
1. ScanTransformQuery will duplicate ScanQuery code with all drawbacks that
we have. Moreover, any fix for ScanQuery should be repeated for
ScanTransformQuery. It will lead to bugs. DRY.
2. If some users want to do transformations for SqlQuery we will introduce
SqlTransformQuery. Right? At this point see previous item.
Transformation logic is some kind of strategy. IMHO, the most convenient
API should get transformation logic as some function provided by user.
On Thu, Feb 4, 2016 at 11:05 PM, Valentin Kulichenko <
valentin.kulichenko@gmail.com> wrote:
> Agree with Sergi. Mixing SQL with Java code transformers is confusing. In
> rare case when it's really required, user can implement a custom function.
>
> I copy-pasted the API to the ticket [1]. Please provide any additional
> comments there.
>
> [1] https://issues.apache.org/jira/browse/IGNITE-2546
>
> -Val
>
> On Thu, Feb 4, 2016 at 10:08 AM, Andrey Gura <ag...@gridgain.com> wrote:
>
> > Sergi,
> >
> >
> > > What you are going to transform remotely here?
> >
> >
> > I'm not going. I believe :)
> >
> > Just hypothetical use case: You have one SqlFieldsQuery but different
> > requirements for returned values. For one case you have to return some
> > string fields as is and for another case you have to trim string to 32
> > characters. Of course you still can trim strings locally but transformers
> > allow you do it remotely.
> >
> > Anyway, this solution can be usefull for rest query types.
> >
> > On Thu, Feb 4, 2016 at 8:54 PM, Sergi Vladykin <sergi.vladykin@gmail.com
> >
> > wrote:
> >
> > > The whole point of Transformer is to do remote transform, how will this
> > > work with SqlFieldsQuery? What you are going to transform remotely
> here?
> > I
> > > believe all the transformations must happen at SQL level here.
> > >
> > > Sergi
> > >
> > >
> > >
> > > 2016-02-04 20:10 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
> > >
> > > > SqlQuery, TextQuery and SpiQuery are similar to ScanQuery because all
> > of
> > > > them also defined as Query<Cache.Entry<>>.
> > > >
> > > > It can be usefull to have one query SqlQuery that can return
> different
> > > > result that will be produced from cache entry by transformer.
> > > >
> > > > Actually only SqlFieldsQuery has different definition. So
> transformers
> > > can
> > > > be applied to any type of query (including SqlFieldsQuery, I
> believe).
> > > >
> > > > On Thu, Feb 4, 2016 at 7:42 PM, Sergi Vladykin <
> > sergi.vladykin@gmail.com
> > > >
> > > > wrote:
> > > >
> > > > > I don't like the idea of having additional method *query(Query<E>
> > qry,
> > > > > Transformer<E, R> transfomer); *because I don't see how these
> > > > transformers
> > > > > will work for example with SQL, but this API makes you think that
> > > > > transformers are supported for all the query types.
> > > > >
> > > > > Sergi
> > > > >
> > > > > 2016-02-04 16:46 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
> > > > >
> > > > > > Val,
> > > > > >
> > > > > > can we introduce new method into IgnteCache API?
> > > > > >
> > > > > > Now we have method: public <R> QueryCursor<R> query(Query<R>
> qry);
> > > > > >
> > > > > > New method will be something like this: <R> QueryCursor<R>
> > > > query(Query<E>
> > > > > > qry, Transformer<E, R> transfomer);
> > > > > >
> > > > > > It allows provide transformers for all query types and chnages
> will
> > > be
> > > > > > related only with query cursor functionality.
> > > > > >
> > > > > > Will it work?
> > > > > >
> > > > > > On Thu, Feb 4, 2016 at 11:13 AM, Andrey Kornev <
> > > > andrewkornev@hotmail.com
> > > > > >
> > > > > > wrote:
> > > > > >
> > > > > > > Another perhaps bigger problem with running queries (including
> > scan
> > > > > > > queries) using closures was discussed at length on the @dev not
> > so
> > > > long
> > > > > > > ago. It has to do with partitions migration due to cluster
> > topology
> > > > > > changes
> > > > > > > which may result in the query returning incomplete result. And
> > > while
> > > > it
> > > > > > is
> > > > > > > possible to solve this problem for the scan queries by using
> some
> > > > > clever
> > > > > > > tricks, all bets are off with the SQL queries.Andrey
> > > > > > > _____________________________
> > > > > > > From: Valentin Kulichenko <va...@gmail.com>
> > > > > > > Sent: Thursday, February 4, 2016 6:29 AM
> > > > > > > Subject: Re: Transformers in SCAN queries
> > > > > > > To: <de...@ignite.apache.org>
> > > > > > >
> > > > > > >
> > > > > > > Dmitry,
> > > > > > >
> > > > > > > The main difference in my view is that you lose pagination
> when
> > > > > sending
> > > > > > > results from servers to client. What if one wants to iterate
> > > through
> > > > > all
> > > > > > > entries in cache?
> > > > > > >
> > > > > > > On Wed, Feb 3, 2016 at 9:47 PM, Dmitriy Setrakyan <
> > > > > > dsetrakyan@apache.org>
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Valentin,
> > > > > > > >
> > > > > > > > Wouldn’t the same effect be achieved by broadcasting a
> closure
> > > to
> > > > > the
> > > > > > > > cluster and executing scan-query on every node locally?
> > > > > > > >
> > > > > > > > D.
> > > > > > > >
> > > > > > > > On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko <
> > > > > > > > valentin.kulichenko@gmail.com> wrote:
> > > > > > > >
> > > > > > > > > Igniters,
> > > > > > > > >
> > > > > > > > > I keep getting requests from our users to add optional
> > > > > transformers
> > > > > > to
> > > > > > > > SCAN
> > > > > > > > > queries. This will allow to iterate through cache, but do
> > not
> > > > > > transfer
> > > > > > > > > whole key-value pairs across networks (e.g., get only
> keys).
> > > The
> > > > > > > feature
> > > > > > > > > looks useful and I created a ticket [1].
> > > > > > > > >
> > > > > > > > > I am struggling with the design now. The problem is that I
> > > > wanted
> > > > > to
> > > > > > > > extend
> > > > > > > > > existing ScanQuery object for this, but this seems to be
> > > > > impossible
> > > > > > > > because
> > > > > > > > > it already extends Query<Cache.Entry<K, V>> and thus can
> > > iterate
> > > > > > only
> > > > > > > > > through entries.
> > > > > > > > >
> > > > > > > > > The only option I see now is to create a separate query
> > type,
> > > > > > > copy-paste
> > > > > > > > > everything from ScanQuery and add *mandatory* transformer.
> > > > > Something
> > > > > > > like
> > > > > > > > > this:
> > > > > > > > >
> > > > > > > > > ScanTransformQuery<K, V, R> extends Query<R> {
> > > > > > > > > IgniteBiPredicate<K, V> filter;
> > > > > > > > > IgniteClosure<Cache.Entry<K, V>, R> transformer;
> > > > > > > > > int part;
> > > > > > > > > ...
> > > > > > > > > }
> > > > > > > > >
> > > > > > > > > Thoughts? Does anyone has other ideas?
> > > > > > > > >
> > > > > > > > > [1] https://issues.apache.org/jira/browse/IGNITE-2546
> > > > > > > > >
> > > > > > > > > -Val
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > --
> > > > > > Andrey Gura
> > > > > > GridGain Systems, Inc.
> > > > > > www.gridgain.com
> > > > > >
> > > > >
> > > >
> > > >
> > > >
> > > > --
> > > > Andrey Gura
> > > > GridGain Systems, Inc.
> > > > www.gridgain.com
> > > >
> > >
> >
> >
> >
> > --
> > Andrey Gura
> > GridGain Systems, Inc.
> > www.gridgain.com
> >
>
--
Andrey Gura
GridGain Systems, Inc.
www.gridgain.com
Re: Transformers in SCAN queries
Posted by Valentin Kulichenko <va...@gmail.com>.
Agree with Sergi. Mixing SQL with Java code transformers is confusing. In
rare case when it's really required, user can implement a custom function.
I copy-pasted the API to the ticket [1]. Please provide any additional
comments there.
[1] https://issues.apache.org/jira/browse/IGNITE-2546
-Val
On Thu, Feb 4, 2016 at 10:08 AM, Andrey Gura <ag...@gridgain.com> wrote:
> Sergi,
>
>
> > What you are going to transform remotely here?
>
>
> I'm not going. I believe :)
>
> Just hypothetical use case: You have one SqlFieldsQuery but different
> requirements for returned values. For one case you have to return some
> string fields as is and for another case you have to trim string to 32
> characters. Of course you still can trim strings locally but transformers
> allow you do it remotely.
>
> Anyway, this solution can be usefull for rest query types.
>
> On Thu, Feb 4, 2016 at 8:54 PM, Sergi Vladykin <se...@gmail.com>
> wrote:
>
> > The whole point of Transformer is to do remote transform, how will this
> > work with SqlFieldsQuery? What you are going to transform remotely here?
> I
> > believe all the transformations must happen at SQL level here.
> >
> > Sergi
> >
> >
> >
> > 2016-02-04 20:10 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
> >
> > > SqlQuery, TextQuery and SpiQuery are similar to ScanQuery because all
> of
> > > them also defined as Query<Cache.Entry<>>.
> > >
> > > It can be usefull to have one query SqlQuery that can return different
> > > result that will be produced from cache entry by transformer.
> > >
> > > Actually only SqlFieldsQuery has different definition. So transformers
> > can
> > > be applied to any type of query (including SqlFieldsQuery, I believe).
> > >
> > > On Thu, Feb 4, 2016 at 7:42 PM, Sergi Vladykin <
> sergi.vladykin@gmail.com
> > >
> > > wrote:
> > >
> > > > I don't like the idea of having additional method *query(Query<E>
> qry,
> > > > Transformer<E, R> transfomer); *because I don't see how these
> > > transformers
> > > > will work for example with SQL, but this API makes you think that
> > > > transformers are supported for all the query types.
> > > >
> > > > Sergi
> > > >
> > > > 2016-02-04 16:46 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
> > > >
> > > > > Val,
> > > > >
> > > > > can we introduce new method into IgnteCache API?
> > > > >
> > > > > Now we have method: public <R> QueryCursor<R> query(Query<R> qry);
> > > > >
> > > > > New method will be something like this: <R> QueryCursor<R>
> > > query(Query<E>
> > > > > qry, Transformer<E, R> transfomer);
> > > > >
> > > > > It allows provide transformers for all query types and chnages will
> > be
> > > > > related only with query cursor functionality.
> > > > >
> > > > > Will it work?
> > > > >
> > > > > On Thu, Feb 4, 2016 at 11:13 AM, Andrey Kornev <
> > > andrewkornev@hotmail.com
> > > > >
> > > > > wrote:
> > > > >
> > > > > > Another perhaps bigger problem with running queries (including
> scan
> > > > > > queries) using closures was discussed at length on the @dev not
> so
> > > long
> > > > > > ago. It has to do with partitions migration due to cluster
> topology
> > > > > changes
> > > > > > which may result in the query returning incomplete result. And
> > while
> > > it
> > > > > is
> > > > > > possible to solve this problem for the scan queries by using some
> > > > clever
> > > > > > tricks, all bets are off with the SQL queries.Andrey
> > > > > > _____________________________
> > > > > > From: Valentin Kulichenko <va...@gmail.com>
> > > > > > Sent: Thursday, February 4, 2016 6:29 AM
> > > > > > Subject: Re: Transformers in SCAN queries
> > > > > > To: <de...@ignite.apache.org>
> > > > > >
> > > > > >
> > > > > > Dmitry,
> > > > > >
> > > > > > The main difference in my view is that you lose pagination when
> > > > sending
> > > > > > results from servers to client. What if one wants to iterate
> > through
> > > > all
> > > > > > entries in cache?
> > > > > >
> > > > > > On Wed, Feb 3, 2016 at 9:47 PM, Dmitriy Setrakyan <
> > > > > dsetrakyan@apache.org>
> > > > > > wrote:
> > > > > >
> > > > > > > Valentin,
> > > > > > >
> > > > > > > Wouldn’t the same effect be achieved by broadcasting a closure
> > to
> > > > the
> > > > > > > cluster and executing scan-query on every node locally?
> > > > > > >
> > > > > > > D.
> > > > > > >
> > > > > > > On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko <
> > > > > > > valentin.kulichenko@gmail.com> wrote:
> > > > > > >
> > > > > > > > Igniters,
> > > > > > > >
> > > > > > > > I keep getting requests from our users to add optional
> > > > transformers
> > > > > to
> > > > > > > SCAN
> > > > > > > > queries. This will allow to iterate through cache, but do
> not
> > > > > transfer
> > > > > > > > whole key-value pairs across networks (e.g., get only keys).
> > The
> > > > > > feature
> > > > > > > > looks useful and I created a ticket [1].
> > > > > > > >
> > > > > > > > I am struggling with the design now. The problem is that I
> > > wanted
> > > > to
> > > > > > > extend
> > > > > > > > existing ScanQuery object for this, but this seems to be
> > > > impossible
> > > > > > > because
> > > > > > > > it already extends Query<Cache.Entry<K, V>> and thus can
> > iterate
> > > > > only
> > > > > > > > through entries.
> > > > > > > >
> > > > > > > > The only option I see now is to create a separate query
> type,
> > > > > > copy-paste
> > > > > > > > everything from ScanQuery and add *mandatory* transformer.
> > > > Something
> > > > > > like
> > > > > > > > this:
> > > > > > > >
> > > > > > > > ScanTransformQuery<K, V, R> extends Query<R> {
> > > > > > > > IgniteBiPredicate<K, V> filter;
> > > > > > > > IgniteClosure<Cache.Entry<K, V>, R> transformer;
> > > > > > > > int part;
> > > > > > > > ...
> > > > > > > > }
> > > > > > > >
> > > > > > > > Thoughts? Does anyone has other ideas?
> > > > > > > >
> > > > > > > > [1] https://issues.apache.org/jira/browse/IGNITE-2546
> > > > > > > >
> > > > > > > > -Val
> > > > > > > >
> > > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > >
> > > > >
> > > > >
> > > > > --
> > > > > Andrey Gura
> > > > > GridGain Systems, Inc.
> > > > > www.gridgain.com
> > > > >
> > > >
> > >
> > >
> > >
> > > --
> > > Andrey Gura
> > > GridGain Systems, Inc.
> > > www.gridgain.com
> > >
> >
>
>
>
> --
> Andrey Gura
> GridGain Systems, Inc.
> www.gridgain.com
>
Re: Transformers in SCAN queries
Posted by Andrey Gura <ag...@gridgain.com>.
Sergi,
> What you are going to transform remotely here?
I'm not going. I believe :)
Just hypothetical use case: You have one SqlFieldsQuery but different
requirements for returned values. For one case you have to return some
string fields as is and for another case you have to trim string to 32
characters. Of course you still can trim strings locally but transformers
allow you do it remotely.
Anyway, this solution can be usefull for rest query types.
On Thu, Feb 4, 2016 at 8:54 PM, Sergi Vladykin <se...@gmail.com>
wrote:
> The whole point of Transformer is to do remote transform, how will this
> work with SqlFieldsQuery? What you are going to transform remotely here? I
> believe all the transformations must happen at SQL level here.
>
> Sergi
>
>
>
> 2016-02-04 20:10 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
>
> > SqlQuery, TextQuery and SpiQuery are similar to ScanQuery because all of
> > them also defined as Query<Cache.Entry<>>.
> >
> > It can be usefull to have one query SqlQuery that can return different
> > result that will be produced from cache entry by transformer.
> >
> > Actually only SqlFieldsQuery has different definition. So transformers
> can
> > be applied to any type of query (including SqlFieldsQuery, I believe).
> >
> > On Thu, Feb 4, 2016 at 7:42 PM, Sergi Vladykin <sergi.vladykin@gmail.com
> >
> > wrote:
> >
> > > I don't like the idea of having additional method *query(Query<E> qry,
> > > Transformer<E, R> transfomer); *because I don't see how these
> > transformers
> > > will work for example with SQL, but this API makes you think that
> > > transformers are supported for all the query types.
> > >
> > > Sergi
> > >
> > > 2016-02-04 16:46 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
> > >
> > > > Val,
> > > >
> > > > can we introduce new method into IgnteCache API?
> > > >
> > > > Now we have method: public <R> QueryCursor<R> query(Query<R> qry);
> > > >
> > > > New method will be something like this: <R> QueryCursor<R>
> > query(Query<E>
> > > > qry, Transformer<E, R> transfomer);
> > > >
> > > > It allows provide transformers for all query types and chnages will
> be
> > > > related only with query cursor functionality.
> > > >
> > > > Will it work?
> > > >
> > > > On Thu, Feb 4, 2016 at 11:13 AM, Andrey Kornev <
> > andrewkornev@hotmail.com
> > > >
> > > > wrote:
> > > >
> > > > > Another perhaps bigger problem with running queries (including scan
> > > > > queries) using closures was discussed at length on the @dev not so
> > long
> > > > > ago. It has to do with partitions migration due to cluster topology
> > > > changes
> > > > > which may result in the query returning incomplete result. And
> while
> > it
> > > > is
> > > > > possible to solve this problem for the scan queries by using some
> > > clever
> > > > > tricks, all bets are off with the SQL queries.Andrey
> > > > > _____________________________
> > > > > From: Valentin Kulichenko <va...@gmail.com>
> > > > > Sent: Thursday, February 4, 2016 6:29 AM
> > > > > Subject: Re: Transformers in SCAN queries
> > > > > To: <de...@ignite.apache.org>
> > > > >
> > > > >
> > > > > Dmitry,
> > > > >
> > > > > The main difference in my view is that you lose pagination when
> > > sending
> > > > > results from servers to client. What if one wants to iterate
> through
> > > all
> > > > > entries in cache?
> > > > >
> > > > > On Wed, Feb 3, 2016 at 9:47 PM, Dmitriy Setrakyan <
> > > > dsetrakyan@apache.org>
> > > > > wrote:
> > > > >
> > > > > > Valentin,
> > > > > >
> > > > > > Wouldn’t the same effect be achieved by broadcasting a closure
> to
> > > the
> > > > > > cluster and executing scan-query on every node locally?
> > > > > >
> > > > > > D.
> > > > > >
> > > > > > On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko <
> > > > > > valentin.kulichenko@gmail.com> wrote:
> > > > > >
> > > > > > > Igniters,
> > > > > > >
> > > > > > > I keep getting requests from our users to add optional
> > > transformers
> > > > to
> > > > > > SCAN
> > > > > > > queries. This will allow to iterate through cache, but do not
> > > > transfer
> > > > > > > whole key-value pairs across networks (e.g., get only keys).
> The
> > > > > feature
> > > > > > > looks useful and I created a ticket [1].
> > > > > > >
> > > > > > > I am struggling with the design now. The problem is that I
> > wanted
> > > to
> > > > > > extend
> > > > > > > existing ScanQuery object for this, but this seems to be
> > > impossible
> > > > > > because
> > > > > > > it already extends Query<Cache.Entry<K, V>> and thus can
> iterate
> > > > only
> > > > > > > through entries.
> > > > > > >
> > > > > > > The only option I see now is to create a separate query type,
> > > > > copy-paste
> > > > > > > everything from ScanQuery and add *mandatory* transformer.
> > > Something
> > > > > like
> > > > > > > this:
> > > > > > >
> > > > > > > ScanTransformQuery<K, V, R> extends Query<R> {
> > > > > > > IgniteBiPredicate<K, V> filter;
> > > > > > > IgniteClosure<Cache.Entry<K, V>, R> transformer;
> > > > > > > int part;
> > > > > > > ...
> > > > > > > }
> > > > > > >
> > > > > > > Thoughts? Does anyone has other ideas?
> > > > > > >
> > > > > > > [1] https://issues.apache.org/jira/browse/IGNITE-2546
> > > > > > >
> > > > > > > -Val
> > > > > > >
> > > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > >
> > > > --
> > > > Andrey Gura
> > > > GridGain Systems, Inc.
> > > > www.gridgain.com
> > > >
> > >
> >
> >
> >
> > --
> > Andrey Gura
> > GridGain Systems, Inc.
> > www.gridgain.com
> >
>
--
Andrey Gura
GridGain Systems, Inc.
www.gridgain.com
Re: Transformers in SCAN queries
Posted by Sergi Vladykin <se...@gmail.com>.
The whole point of Transformer is to do remote transform, how will this
work with SqlFieldsQuery? What you are going to transform remotely here? I
believe all the transformations must happen at SQL level here.
Sergi
2016-02-04 20:10 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
> SqlQuery, TextQuery and SpiQuery are similar to ScanQuery because all of
> them also defined as Query<Cache.Entry<>>.
>
> It can be usefull to have one query SqlQuery that can return different
> result that will be produced from cache entry by transformer.
>
> Actually only SqlFieldsQuery has different definition. So transformers can
> be applied to any type of query (including SqlFieldsQuery, I believe).
>
> On Thu, Feb 4, 2016 at 7:42 PM, Sergi Vladykin <se...@gmail.com>
> wrote:
>
> > I don't like the idea of having additional method *query(Query<E> qry,
> > Transformer<E, R> transfomer); *because I don't see how these
> transformers
> > will work for example with SQL, but this API makes you think that
> > transformers are supported for all the query types.
> >
> > Sergi
> >
> > 2016-02-04 16:46 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
> >
> > > Val,
> > >
> > > can we introduce new method into IgnteCache API?
> > >
> > > Now we have method: public <R> QueryCursor<R> query(Query<R> qry);
> > >
> > > New method will be something like this: <R> QueryCursor<R>
> query(Query<E>
> > > qry, Transformer<E, R> transfomer);
> > >
> > > It allows provide transformers for all query types and chnages will be
> > > related only with query cursor functionality.
> > >
> > > Will it work?
> > >
> > > On Thu, Feb 4, 2016 at 11:13 AM, Andrey Kornev <
> andrewkornev@hotmail.com
> > >
> > > wrote:
> > >
> > > > Another perhaps bigger problem with running queries (including scan
> > > > queries) using closures was discussed at length on the @dev not so
> long
> > > > ago. It has to do with partitions migration due to cluster topology
> > > changes
> > > > which may result in the query returning incomplete result. And while
> it
> > > is
> > > > possible to solve this problem for the scan queries by using some
> > clever
> > > > tricks, all bets are off with the SQL queries.Andrey
> > > > _____________________________
> > > > From: Valentin Kulichenko <va...@gmail.com>
> > > > Sent: Thursday, February 4, 2016 6:29 AM
> > > > Subject: Re: Transformers in SCAN queries
> > > > To: <de...@ignite.apache.org>
> > > >
> > > >
> > > > Dmitry,
> > > >
> > > > The main difference in my view is that you lose pagination when
> > sending
> > > > results from servers to client. What if one wants to iterate through
> > all
> > > > entries in cache?
> > > >
> > > > On Wed, Feb 3, 2016 at 9:47 PM, Dmitriy Setrakyan <
> > > dsetrakyan@apache.org>
> > > > wrote:
> > > >
> > > > > Valentin,
> > > > >
> > > > > Wouldn’t the same effect be achieved by broadcasting a closure to
> > the
> > > > > cluster and executing scan-query on every node locally?
> > > > >
> > > > > D.
> > > > >
> > > > > On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko <
> > > > > valentin.kulichenko@gmail.com> wrote:
> > > > >
> > > > > > Igniters,
> > > > > >
> > > > > > I keep getting requests from our users to add optional
> > transformers
> > > to
> > > > > SCAN
> > > > > > queries. This will allow to iterate through cache, but do not
> > > transfer
> > > > > > whole key-value pairs across networks (e.g., get only keys). The
> > > > feature
> > > > > > looks useful and I created a ticket [1].
> > > > > >
> > > > > > I am struggling with the design now. The problem is that I
> wanted
> > to
> > > > > extend
> > > > > > existing ScanQuery object for this, but this seems to be
> > impossible
> > > > > because
> > > > > > it already extends Query<Cache.Entry<K, V>> and thus can iterate
> > > only
> > > > > > through entries.
> > > > > >
> > > > > > The only option I see now is to create a separate query type,
> > > > copy-paste
> > > > > > everything from ScanQuery and add *mandatory* transformer.
> > Something
> > > > like
> > > > > > this:
> > > > > >
> > > > > > ScanTransformQuery<K, V, R> extends Query<R> {
> > > > > > IgniteBiPredicate<K, V> filter;
> > > > > > IgniteClosure<Cache.Entry<K, V>, R> transformer;
> > > > > > int part;
> > > > > > ...
> > > > > > }
> > > > > >
> > > > > > Thoughts? Does anyone has other ideas?
> > > > > >
> > > > > > [1] https://issues.apache.org/jira/browse/IGNITE-2546
> > > > > >
> > > > > > -Val
> > > > > >
> > > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > >
> > > --
> > > Andrey Gura
> > > GridGain Systems, Inc.
> > > www.gridgain.com
> > >
> >
>
>
>
> --
> Andrey Gura
> GridGain Systems, Inc.
> www.gridgain.com
>
Re: Transformers in SCAN queries
Posted by Andrey Gura <ag...@gridgain.com>.
SqlQuery, TextQuery and SpiQuery are similar to ScanQuery because all of
them also defined as Query<Cache.Entry<>>.
It can be usefull to have one query SqlQuery that can return different
result that will be produced from cache entry by transformer.
Actually only SqlFieldsQuery has different definition. So transformers can
be applied to any type of query (including SqlFieldsQuery, I believe).
On Thu, Feb 4, 2016 at 7:42 PM, Sergi Vladykin <se...@gmail.com>
wrote:
> I don't like the idea of having additional method *query(Query<E> qry,
> Transformer<E, R> transfomer); *because I don't see how these transformers
> will work for example with SQL, but this API makes you think that
> transformers are supported for all the query types.
>
> Sergi
>
> 2016-02-04 16:46 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
>
> > Val,
> >
> > can we introduce new method into IgnteCache API?
> >
> > Now we have method: public <R> QueryCursor<R> query(Query<R> qry);
> >
> > New method will be something like this: <R> QueryCursor<R> query(Query<E>
> > qry, Transformer<E, R> transfomer);
> >
> > It allows provide transformers for all query types and chnages will be
> > related only with query cursor functionality.
> >
> > Will it work?
> >
> > On Thu, Feb 4, 2016 at 11:13 AM, Andrey Kornev <andrewkornev@hotmail.com
> >
> > wrote:
> >
> > > Another perhaps bigger problem with running queries (including scan
> > > queries) using closures was discussed at length on the @dev not so long
> > > ago. It has to do with partitions migration due to cluster topology
> > changes
> > > which may result in the query returning incomplete result. And while it
> > is
> > > possible to solve this problem for the scan queries by using some
> clever
> > > tricks, all bets are off with the SQL queries.Andrey
> > > _____________________________
> > > From: Valentin Kulichenko <va...@gmail.com>
> > > Sent: Thursday, February 4, 2016 6:29 AM
> > > Subject: Re: Transformers in SCAN queries
> > > To: <de...@ignite.apache.org>
> > >
> > >
> > > Dmitry,
> > >
> > > The main difference in my view is that you lose pagination when
> sending
> > > results from servers to client. What if one wants to iterate through
> all
> > > entries in cache?
> > >
> > > On Wed, Feb 3, 2016 at 9:47 PM, Dmitriy Setrakyan <
> > dsetrakyan@apache.org>
> > > wrote:
> > >
> > > > Valentin,
> > > >
> > > > Wouldn’t the same effect be achieved by broadcasting a closure to
> the
> > > > cluster and executing scan-query on every node locally?
> > > >
> > > > D.
> > > >
> > > > On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko <
> > > > valentin.kulichenko@gmail.com> wrote:
> > > >
> > > > > Igniters,
> > > > >
> > > > > I keep getting requests from our users to add optional
> transformers
> > to
> > > > SCAN
> > > > > queries. This will allow to iterate through cache, but do not
> > transfer
> > > > > whole key-value pairs across networks (e.g., get only keys). The
> > > feature
> > > > > looks useful and I created a ticket [1].
> > > > >
> > > > > I am struggling with the design now. The problem is that I wanted
> to
> > > > extend
> > > > > existing ScanQuery object for this, but this seems to be
> impossible
> > > > because
> > > > > it already extends Query<Cache.Entry<K, V>> and thus can iterate
> > only
> > > > > through entries.
> > > > >
> > > > > The only option I see now is to create a separate query type,
> > > copy-paste
> > > > > everything from ScanQuery and add *mandatory* transformer.
> Something
> > > like
> > > > > this:
> > > > >
> > > > > ScanTransformQuery<K, V, R> extends Query<R> {
> > > > > IgniteBiPredicate<K, V> filter;
> > > > > IgniteClosure<Cache.Entry<K, V>, R> transformer;
> > > > > int part;
> > > > > ...
> > > > > }
> > > > >
> > > > > Thoughts? Does anyone has other ideas?
> > > > >
> > > > > [1] https://issues.apache.org/jira/browse/IGNITE-2546
> > > > >
> > > > > -Val
> > > > >
> > > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
> > --
> > Andrey Gura
> > GridGain Systems, Inc.
> > www.gridgain.com
> >
>
--
Andrey Gura
GridGain Systems, Inc.
www.gridgain.com
Re: Transformers in SCAN queries
Posted by Sergi Vladykin <se...@gmail.com>.
I don't like the idea of having additional method *query(Query<E> qry,
Transformer<E, R> transfomer); *because I don't see how these transformers
will work for example with SQL, but this API makes you think that
transformers are supported for all the query types.
Sergi
2016-02-04 16:46 GMT+03:00 Andrey Gura <ag...@gridgain.com>:
> Val,
>
> can we introduce new method into IgnteCache API?
>
> Now we have method: public <R> QueryCursor<R> query(Query<R> qry);
>
> New method will be something like this: <R> QueryCursor<R> query(Query<E>
> qry, Transformer<E, R> transfomer);
>
> It allows provide transformers for all query types and chnages will be
> related only with query cursor functionality.
>
> Will it work?
>
> On Thu, Feb 4, 2016 at 11:13 AM, Andrey Kornev <an...@hotmail.com>
> wrote:
>
> > Another perhaps bigger problem with running queries (including scan
> > queries) using closures was discussed at length on the @dev not so long
> > ago. It has to do with partitions migration due to cluster topology
> changes
> > which may result in the query returning incomplete result. And while it
> is
> > possible to solve this problem for the scan queries by using some clever
> > tricks, all bets are off with the SQL queries.Andrey
> > _____________________________
> > From: Valentin Kulichenko <va...@gmail.com>
> > Sent: Thursday, February 4, 2016 6:29 AM
> > Subject: Re: Transformers in SCAN queries
> > To: <de...@ignite.apache.org>
> >
> >
> > Dmitry,
> >
> > The main difference in my view is that you lose pagination when sending
> > results from servers to client. What if one wants to iterate through all
> > entries in cache?
> >
> > On Wed, Feb 3, 2016 at 9:47 PM, Dmitriy Setrakyan <
> dsetrakyan@apache.org>
> > wrote:
> >
> > > Valentin,
> > >
> > > Wouldn’t the same effect be achieved by broadcasting a closure to the
> > > cluster and executing scan-query on every node locally?
> > >
> > > D.
> > >
> > > On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko <
> > > valentin.kulichenko@gmail.com> wrote:
> > >
> > > > Igniters,
> > > >
> > > > I keep getting requests from our users to add optional transformers
> to
> > > SCAN
> > > > queries. This will allow to iterate through cache, but do not
> transfer
> > > > whole key-value pairs across networks (e.g., get only keys). The
> > feature
> > > > looks useful and I created a ticket [1].
> > > >
> > > > I am struggling with the design now. The problem is that I wanted to
> > > extend
> > > > existing ScanQuery object for this, but this seems to be impossible
> > > because
> > > > it already extends Query<Cache.Entry<K, V>> and thus can iterate
> only
> > > > through entries.
> > > >
> > > > The only option I see now is to create a separate query type,
> > copy-paste
> > > > everything from ScanQuery and add *mandatory* transformer. Something
> > like
> > > > this:
> > > >
> > > > ScanTransformQuery<K, V, R> extends Query<R> {
> > > > IgniteBiPredicate<K, V> filter;
> > > > IgniteClosure<Cache.Entry<K, V>, R> transformer;
> > > > int part;
> > > > ...
> > > > }
> > > >
> > > > Thoughts? Does anyone has other ideas?
> > > >
> > > > [1] https://issues.apache.org/jira/browse/IGNITE-2546
> > > >
> > > > -Val
> > > >
> > >
> >
> >
> >
> >
> >
>
>
>
> --
> Andrey Gura
> GridGain Systems, Inc.
> www.gridgain.com
>
Re: Transformers in SCAN queries
Posted by Andrey Gura <ag...@gridgain.com>.
Val,
can we introduce new method into IgnteCache API?
Now we have method: public <R> QueryCursor<R> query(Query<R> qry);
New method will be something like this: <R> QueryCursor<R> query(Query<E>
qry, Transformer<E, R> transfomer);
It allows provide transformers for all query types and chnages will be
related only with query cursor functionality.
Will it work?
On Thu, Feb 4, 2016 at 11:13 AM, Andrey Kornev <an...@hotmail.com>
wrote:
> Another perhaps bigger problem with running queries (including scan
> queries) using closures was discussed at length on the @dev not so long
> ago. It has to do with partitions migration due to cluster topology changes
> which may result in the query returning incomplete result. And while it is
> possible to solve this problem for the scan queries by using some clever
> tricks, all bets are off with the SQL queries.Andrey
> _____________________________
> From: Valentin Kulichenko <va...@gmail.com>
> Sent: Thursday, February 4, 2016 6:29 AM
> Subject: Re: Transformers in SCAN queries
> To: <de...@ignite.apache.org>
>
>
> Dmitry,
>
> The main difference in my view is that you lose pagination when sending
> results from servers to client. What if one wants to iterate through all
> entries in cache?
>
> On Wed, Feb 3, 2016 at 9:47 PM, Dmitriy Setrakyan <ds...@apache.org>
> wrote:
>
> > Valentin,
> >
> > Wouldn’t the same effect be achieved by broadcasting a closure to the
> > cluster and executing scan-query on every node locally?
> >
> > D.
> >
> > On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko <
> > valentin.kulichenko@gmail.com> wrote:
> >
> > > Igniters,
> > >
> > > I keep getting requests from our users to add optional transformers to
> > SCAN
> > > queries. This will allow to iterate through cache, but do not transfer
> > > whole key-value pairs across networks (e.g., get only keys). The
> feature
> > > looks useful and I created a ticket [1].
> > >
> > > I am struggling with the design now. The problem is that I wanted to
> > extend
> > > existing ScanQuery object for this, but this seems to be impossible
> > because
> > > it already extends Query<Cache.Entry<K, V>> and thus can iterate only
> > > through entries.
> > >
> > > The only option I see now is to create a separate query type,
> copy-paste
> > > everything from ScanQuery and add *mandatory* transformer. Something
> like
> > > this:
> > >
> > > ScanTransformQuery<K, V, R> extends Query<R> {
> > > IgniteBiPredicate<K, V> filter;
> > > IgniteClosure<Cache.Entry<K, V>, R> transformer;
> > > int part;
> > > ...
> > > }
> > >
> > > Thoughts? Does anyone has other ideas?
> > >
> > > [1] https://issues.apache.org/jira/browse/IGNITE-2546
> > >
> > > -Val
> > >
> >
>
>
>
>
>
--
Andrey Gura
GridGain Systems, Inc.
www.gridgain.com
Re: Transformers in SCAN queries
Posted by Andrey Kornev <an...@hotmail.com>.
Another perhaps bigger problem with running queries (including scan queries) using closures was discussed at length on the @dev not so long ago. It has to do with partitions migration due to cluster topology changes which may result in the query returning incomplete result. And while it is possible to solve this problem for the scan queries by using some clever tricks, all bets are off with the SQL queries.Andrey
_____________________________
From: Valentin Kulichenko <va...@gmail.com>
Sent: Thursday, February 4, 2016 6:29 AM
Subject: Re: Transformers in SCAN queries
To: <de...@ignite.apache.org>
Dmitry,
The main difference in my view is that you lose pagination when sending
results from servers to client. What if one wants to iterate through all
entries in cache?
On Wed, Feb 3, 2016 at 9:47 PM, Dmitriy Setrakyan <ds...@apache.org>
wrote:
> Valentin,
>
> Wouldn’t the same effect be achieved by broadcasting a closure to the
> cluster and executing scan-query on every node locally?
>
> D.
>
> On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko <
> valentin.kulichenko@gmail.com> wrote:
>
> > Igniters,
> >
> > I keep getting requests from our users to add optional transformers to
> SCAN
> > queries. This will allow to iterate through cache, but do not transfer
> > whole key-value pairs across networks (e.g., get only keys). The feature
> > looks useful and I created a ticket [1].
> >
> > I am struggling with the design now. The problem is that I wanted to
> extend
> > existing ScanQuery object for this, but this seems to be impossible
> because
> > it already extends Query<Cache.Entry<K, V>> and thus can iterate only
> > through entries.
> >
> > The only option I see now is to create a separate query type, copy-paste
> > everything from ScanQuery and add *mandatory* transformer. Something like
> > this:
> >
> > ScanTransformQuery<K, V, R> extends Query<R> {
> > IgniteBiPredicate<K, V> filter;
> > IgniteClosure<Cache.Entry<K, V>, R> transformer;
> > int part;
> > ...
> > }
> >
> > Thoughts? Does anyone has other ideas?
> >
> > [1] https://issues.apache.org/jira/browse/IGNITE-2546
> >
> > -Val
> >
>
Re: Transformers in SCAN queries
Posted by Valentin Kulichenko <va...@gmail.com>.
Dmitry,
The main difference in my view is that you lose pagination when sending
results from servers to client. What if one wants to iterate through all
entries in cache?
On Wed, Feb 3, 2016 at 9:47 PM, Dmitriy Setrakyan <ds...@apache.org>
wrote:
> Valentin,
>
> Wouldn’t the same effect be achieved by broadcasting a closure to the
> cluster and executing scan-query on every node locally?
>
> D.
>
> On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko <
> valentin.kulichenko@gmail.com> wrote:
>
> > Igniters,
> >
> > I keep getting requests from our users to add optional transformers to
> SCAN
> > queries. This will allow to iterate through cache, but do not transfer
> > whole key-value pairs across networks (e.g., get only keys). The feature
> > looks useful and I created a ticket [1].
> >
> > I am struggling with the design now. The problem is that I wanted to
> extend
> > existing ScanQuery object for this, but this seems to be impossible
> because
> > it already extends Query<Cache.Entry<K, V>> and thus can iterate only
> > through entries.
> >
> > The only option I see now is to create a separate query type, copy-paste
> > everything from ScanQuery and add *mandatory* transformer. Something like
> > this:
> >
> > ScanTransformQuery<K, V, R> extends Query<R> {
> > IgniteBiPredicate<K, V> filter;
> > IgniteClosure<Cache.Entry<K, V>, R> transformer;
> > int part;
> > ...
> > }
> >
> > Thoughts? Does anyone has other ideas?
> >
> > [1] https://issues.apache.org/jira/browse/IGNITE-2546
> >
> > -Val
> >
>
Re: Transformers in SCAN queries
Posted by Dmitriy Setrakyan <ds...@apache.org>.
Valentin,
Wouldn’t the same effect be achieved by broadcasting a closure to the
cluster and executing scan-query on every node locally?
D.
On Wed, Feb 3, 2016 at 9:17 PM, Valentin Kulichenko <
valentin.kulichenko@gmail.com> wrote:
> Igniters,
>
> I keep getting requests from our users to add optional transformers to SCAN
> queries. This will allow to iterate through cache, but do not transfer
> whole key-value pairs across networks (e.g., get only keys). The feature
> looks useful and I created a ticket [1].
>
> I am struggling with the design now. The problem is that I wanted to extend
> existing ScanQuery object for this, but this seems to be impossible because
> it already extends Query<Cache.Entry<K, V>> and thus can iterate only
> through entries.
>
> The only option I see now is to create a separate query type, copy-paste
> everything from ScanQuery and add *mandatory* transformer. Something like
> this:
>
> ScanTransformQuery<K, V, R> extends Query<R> {
> IgniteBiPredicate<K, V> filter;
> IgniteClosure<Cache.Entry<K, V>, R> transformer;
> int part;
> ...
> }
>
> Thoughts? Does anyone has other ideas?
>
> [1] https://issues.apache.org/jira/browse/IGNITE-2546
>
> -Val
>