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From Alex Plehanov <plehanov.a...@gmail.com>
Subject Re: Thin client: transactions support
Date Tue, 30 Apr 2019 10:24:28 GMT
Hello, Igniters!

I've update IEP [1] and implement PoC according to new approach (multiple
concurrent transactions per connection).
But to move forward another feature need to be implemented: suspend/resume
for pessimistic transactions (IGNITE-5714 [2]). Implementation of
suspend/resume is ready now and ticket in 'Patch available' status. Can any
transactions expert help with review of IGNITE-5714?

[1]:
https://cwiki.apache.org/confluence/display/IGNITE/IEP-34+Thin+client%3A+transactions+support
[2]: https://issues.apache.org/jira/browse/IGNITE-5714

чт, 4 апр. 2019 г. в 11:32, Alex Plehanov <plehanov.alex@gmail.com>:

> Vladimir,
>
> Ok, then I will rewrite IEP in the near future.
>
> чт, 4 апр. 2019 г. в 11:14, Vladimir Ozerov <vozerov@gridgain.com>:
>
>> Hi Alex,
>>
>> I think we should be able to handle many transactions through a single
>> connection. This will make our protocol and client implementations much
>> more efficient, and simplicity from developer's perspective is not our
>> goal. Consider normal nodes. We have server nodes and client nodes. You
>> may
>> span whatever number of transactions you need, but all of them are
>> coordinated through a single connection. The same should be applicable to
>> thin clients. Protocol is already designed to handle this, as we pass
>> unique operation ID in order to distinguish one operation from another. It
>> is true, though, that we will have to introduce a kind of "session"
>> concept, and pass additional identifier along with cache operations, but
>> this doesn't sound like a problem to me.
>>
>> And provided that currently server-side transactions are bound to threads
>> artificially, I would say that the first step in implementation of
>> transactions on thin clients should be decoupling server-side transactions
>> from threads. Without this we will have very inefficient implementation,
>> when every new client transaction have to spawn a new thread. This is slow
>> and introduces high memory pressure on a cluster node. We already work
>> this
>> way for MVCC transactions which are spawned from JDBC driver, and believe
>> me, we do not want to replicated this bad practice to other clients :-)
>>
>> Vladimir.
>>
>> On Thu, Apr 4, 2019 at 10:08 AM Alex Plehanov <plehanov.alex@gmail.com>
>> wrote:
>>
>> > Guys, so, do we need multiple concurrent transactions per connection?
>> >
>> > There are pros and cons for each approach. Difference between
>> approaches:
>> >
>> > One transaction at a time per connection:
>> >  - This approach is used in RDBMS world and users got used to it
>> >  - To use transactions concurrently users need to use different
>> connections
>> > and get these connections via something like a connection pool
>> >  - Easy to implement (in fact, PoC is already done)
>> >
>> > Multiple concurrent transactions per connection:
>> >  - At least for java thin client, we can implement transaction per
>> thread
>> > approach as implemented now for the thick client (perhaps other thin
>> > clients can implement the same abstraction)
>> >  - There is also protocol change for all cache operations needed (to
>> bind
>> > cache operation to the transaction)
>> >  - Significant changes to all implemented clients are needed
>> >  - Implementation on the server side is more complex
>> >
>> > What do you think?
>> >
>> >
>> > вт, 2 апр. 2019 г. в 16:29, Alex Plehanov <plehanov.alex@gmail.com>:
>> >
>> > > Ilya,
>> > >
>> > > > We should be able to multiplex several transactions using a single
>> > > Client connection.
>> > > In this case, we should significantly change cache operations syntax
>> (for
>> > > each implemented client), to bind each operation to the transaction.
>> > >
>> > > > I want to also ask if "Number of entries participating in
>> transaction
>> > > (may be approximate). 0 - default value." is needed.
>> > > I've tried to minimize API changes between thick and thin client to
>> > > simplify move from one to another. It's the only reason. But I agree
>> with
>> > > you, the parameter is not very useful.
>> > >
>> > >
>> > > вт, 2 апр. 2019 г. в 14:48, Ilya Kasnacheev <
>> ilya.kasnacheev@gmail.com>:
>> > >
>> > >> Hello!
>> > >>
>> > >> Pavel, I agree with you thorougly. We should be able to multiplex
>> > several
>> > >> transactions using a single Client connection. This means adding
>> > >> Transaction id parameter to every affected cache operation / SQL
>> > statement
>> > >> (if applicable) to make sure we do cache operations on relevant
>> > >> transaction.
>> > >>
>> > >> This is how other things work in Ignite, such as communication. We do
>> > not
>> > >> open dozens of connections, we multiplex operations asynchronously
>> > through
>> > >> a single connection.
>> > >>
>> > >> I think that trying to pool Ignite connections will be highly
>> > >> inconvenient,
>> > >> since there is no existing infrastructure for such pooling (like
>> there
>> > >> exists for JDBC).
>> > >>
>> > >> I want to also ask if "Number of entries participating in transaction
>> > (may
>> > >> be approximate). 0 - default value." is needed. Does it actually do
>> > >> anything in our tx protocol? Users of existing APIs are already
>> confused
>> > >> by
>> > >> this parameter, if we could get rid of it in thin client protocol it
>> > would
>> > >> be nice clean-up.
>> > >>
>> > >> Regards,
>> > >> --
>> > >> Ilya Kasnacheev
>> > >>
>> > >>
>> > >> вт, 2 апр. 2019 г. в 09:55, Pavel Tupitsyn <ptupitsyn@apache.org>:
>> > >>
>> > >> > Alex,
>> > >> >
>> > >> > > now we can only support one active transaction per connection
>> > >> >
>> > >> > I totally understand server-side and protocol limitations that are
>> > >> causing
>> > >> > this.
>> > >> > But I have no idea how to support this in .NET Thin Client, for
>> > example.
>> > >> >
>> > >> > It is thread-safe and can handle multiple async operations in
>> > parallel.
>> > >> > But with TX support we have to somehow switch to single-threaded
>> mode
>> > to
>> > >> > avoid unexpected effects.
>> > >> >
>> > >> > Any ideas?
>> > >> >
>> > >> >
>> > >> > On Mon, Apr 1, 2019 at 6:38 PM Alex Plehanov <
>> plehanov.alex@gmail.com
>> > >
>> > >> > wrote:
>> > >> >
>> > >> > > Dmitriy, thank you!
>> > >> > >
>> > >> > > Guys, I've created the IEP [1] on wiki, please have a look.
>> > >> > >
>> > >> > > [1]
>> > >> > >
>> > >> > >
>> > >> >
>> > >>
>> >
>> https://cwiki.apache.org/confluence/display/IGNITE/IEP-34+Thin+client%3A+transactions+support
>> > >> > >
>> > >> > >
>> > >> > > чт, 28 мар. 2019 г. в 14:33, Dmitriy Pavlov <dpavlov@apache.org
>> >:
>> > >> > >
>> > >> > > > Hi,
>> > >> > > >
>> > >> > > > I've added permissions to account plehanov.alex
>> > >> > > >
>> > >> > > > Recently Infra integrated Apache LDAP with confluence, so it is
>> > >> > possible
>> > >> > > to
>> > >> > > > login using Apache credentials. Probably we can ask infra if
>> extra
>> > >> > > > permissions to edit pages should be added for committers.
>> > >> > > >
>> > >> > > > Sincerely,
>> > >> > > > Dmitriy Pavlov
>> > >> > > >
>> > >> > > > ср, 27 мар. 2019 г. в 13:37, Alex Plehanov <
>> > plehanov.alex@gmail.com
>> > >> >:
>> > >> > > >
>> > >> > > > > Vladimir,
>> > >> > > > >
>> > >> > > > > About current tx: ok, then we don't need tx() method in the
>> > >> interface
>> > >> > > at
>> > >> > > > > all (the same cached transaction info user can store by
>> > himself).
>> > >> > > > >
>> > >> > > > > About decoupling transactions from threads on the server
>> side:
>> > for
>> > >> > now,
>> > >> > > > we
>> > >> > > > > can start with thread-per-connection approach (we only can
>> > support
>> > >> > one
>> > >> > > > > active transaction per connection, see below, so we need one
>> > >> > additional
>> > >> > > > > dedicated thread for each connection with active
>> transaction),
>> > and
>> > >> > > later
>> > >> > > > > change server-side internals to process client transactions
>> in
>> > any
>> > >> > > server
>> > >> > > > > thread (not dedicated to this connection). This change will
>> not
>> > >> > affect
>> > >> > > > the
>> > >> > > > > thin client protocol, it only affects the server side.
>> > >> > > > > In any case, we can't support concurrent transactions per
>> > >> connection
>> > >> > on
>> > >> > > > > the client side without fundamental changes to the current
>> > >> protocol
>> > >> > > > (cache
>> > >> > > > > operation doesn't bound to transaction or thread and the
>> server
>> > >> > doesn't
>> > >> > > > > know which thread on the client side do this cache
>> operation).
>> > In
>> > >> my
>> > >> > > > > opinion, if a user wants to use concurrent transactions, he
>> must
>> > >> use
>> > >> > > > > different connections from a connection pool.
>> > >> > > > >
>> > >> > > > > About semantics of suspend/resume on the client-side: it's
>> > >> absolutely
>> > >> > > > > different than server-side semantics (we don't need to do
>> > >> > > suspend/resume
>> > >> > > > to
>> > >> > > > > pass transaction between threads on the client-side), but
>> can't
>> > be
>> > >> > > > > implemented efficiently without implemented suspend/resume on
>> > >> > > > server-side.
>> > >> > > > >
>> > >> > > > > Can anyone give me permissions to create IEP on Apache wiki?
>> > >> > > > >
>> > >> > > > > ср, 27 мар. 2019 г. в 11:59, Vladimir Ozerov <
>> > >> vozerov@gridgain.com>:
>> > >> > > > >
>> > >> > > > > > Hi Alex,
>> > >> > > > > >
>> > >> > > > > > My comments was only about the protocol. Getting current
>> info
>> > >> about
>> > >> > > > > > transaction should be handled by the client itself. It is
>> not
>> > >> > > protocl's
>> > >> > > > > > concern. Same about other APIs and behavior in case another
>> > >> > > transaction
>> > >> > > > > is
>> > >> > > > > > attempted from the same thread.
>> > >> > > > > >
>> > >> > > > > > Putting protocol aside, transaction support is complicated
>> > >> matter.
>> > >> > I
>> > >> > > > > would
>> > >> > > > > > propose to route through IEP and wide community
>> discussion. We
>> > >> need
>> > >> > > to
>> > >> > > > > > review API and semantics very carefully, taking
>> SUSPEND/RESUME
>> > >> in
>> > >> > > > count.
>> > >> > > > > > Also I do not see how we support client transactions
>> > efficiently
>> > >> > > > without
>> > >> > > > > > decoupling transactions from threads on the server side
>> first.
>> > >> > > Because
>> > >> > > > > > without it you will need a dedicated server thread for
>> every
>> > >> > client's
>> > >> > > > > > transaction which is slow and may even crash the server.
>> > >> > > > > >
>> > >> > > > > > Vladimir.
>> > >> > > > > >
>> > >> > > > > > On Wed, Mar 27, 2019 at 11:44 AM Alex Plehanov <
>> > >> > > > plehanov.alex@gmail.com>
>> > >> > > > > > wrote:
>> > >> > > > > >
>> > >> > > > > > > Vladimir, what if we want to get current transaction info
>> > >> (tx()
>> > >> > > > > method)?
>> > >> > > > > > >
>> > >> > > > > > > Does close() method mapped to TX_END(rollback)?
>> > >> > > > > > >
>> > >> > > > > > > For example, this code:
>> > >> > > > > > >
>> > >> > > > > > > try(tx = txStart()) {
>> > >> > > > > > >     tx.commit();
>> > >> > > > > > > }
>> > >> > > > > > >
>> > >> > > > > > > Will produce:
>> > >> > > > > > > TX_START
>> > >> > > > > > > TX_END(commit)
>> > >> > > > > > > TX_END(rollback)
>> > >> > > > > > >
>> > >> > > > > > > Am I understand you right?
>> > >> > > > > > >
>> > >> > > > > > > About xid. There is yet another proposal. Use some unique
>> > per
>> > >> > > > > connection
>> > >> > > > > > id
>> > >> > > > > > > (integer, simple counter) for identifying the
>> transaction on
>> > >> > > > > > > commit/rollback message. The client gets this id from the
>> > >> server
>> > >> > > with
>> > >> > > > > > > transaction info and sends it back to the server when
>> trying
>> > >> to
>> > >> > > > > > > commit/rollback transaction. This id is not shown to
>> users.
>> > >> But
>> > >> > > also
>> > >> > > > we
>> > >> > > > > > can
>> > >> > > > > > > pass from server to client real transaction id (xid) with
>> > >> > > transaction
>> > >> > > > > > info
>> > >> > > > > > > for diagnostic purposes.
>> > >> > > > > > >
>> > >> > > > > > > And one more question: what should we do if the client
>> > starts
>> > >> a
>> > >> > new
>> > >> > > > > > > transaction without ending the old one? Should we end the
>> > old
>> > >> > > > > transaction
>> > >> > > > > > > implicitly (rollback) or throw an exception to the
>> client?
>> > In
>> > >> my
>> > >> > > > > opinion,
>> > >> > > > > > > the first option is better. For example, if we got a
>> > >> previously
>> > >> > > used
>> > >> > > > > > > connection from the connection pool, we should not worry
>> > about
>> > >> > any
>> > >> > > > > > > uncompleted transaction started by the previous user of
>> this
>> > >> > > > > connection.
>> > >> > > > > > >
>> > >> > > > > > > ср, 27 мар. 2019 г. в 11:02, Vladimir Ozerov <
>> > >> > vozerov@gridgain.com
>> > >> > > >:
>> > >> > > > > > >
>> > >> > > > > > > > As far as SUSPEND/RESUME/SAVEPOINT - we do not support
>> > them
>> > >> > yet,
>> > >> > > > and
>> > >> > > > > > > adding
>> > >> > > > > > > > them in future should not conflict with simple
>> START/END
>> > >> > > > > > infrastructure.
>> > >> > > > > > > >
>> > >> > > > > > > > On Wed, Mar 27, 2019 at 11:00 AM Vladimir Ozerov <
>> > >> > > > > vozerov@gridgain.com
>> > >> > > > > > >
>> > >> > > > > > > > wrote:
>> > >> > > > > > > >
>> > >> > > > > > > > > Hi Alex,
>> > >> > > > > > > > >
>> > >> > > > > > > > > I am not sure we need 5 commands. Wouldn't it be
>> enough
>> > to
>> > >> > have
>> > >> > > > > only
>> > >> > > > > > > two?
>> > >> > > > > > > > >
>> > >> > > > > > > > > START - accepts optional parameters, returns
>> transaction
>> > >> info
>> > >> > > > > > > > > END - provides commit flag, returns void
>> > >> > > > > > > > >
>> > >> > > > > > > > > Vladimir.
>> > >> > > > > > > > >
>> > >> > > > > > > > > On Wed, Mar 27, 2019 at 8:26 AM Alex Plehanov <
>> > >> > > > > > plehanov.alex@gmail.com
>> > >> > > > > > > >
>> > >> > > > > > > > > wrote:
>> > >> > > > > > > > >
>> > >> > > > > > > > >> Sergey, yes, the close is something like silent
>> > rollback.
>> > >> > But
>> > >> > > we
>> > >> > > > > can
>> > >> > > > > > > > >> also implement this on the client side, just using
>> > >> rollback
>> > >> > > and
>> > >> > > > > > > ignoring
>> > >> > > > > > > > >> errors in the response.
>> > >> > > > > > > > >>
>> > >> > > > > > > > >> ср, 27 мар. 2019 г. в 00:04, Sergey Kozlov <
>> > >> > > > skozlov@gridgain.com
>> > >> > > > > >:
>> > >> > > > > > > > >>
>> > >> > > > > > > > >> > Nikolay
>> > >> > > > > > > > >> >
>> > >> > > > > > > > >> > Am I correctly understand you points:
>> > >> > > > > > > > >> >
>> > >> > > > > > > > >> >    - close: rollback
>> > >> > > > > > > > >> >    - commit, close: do nothing
>> > >> > > > > > > > >> >    - rollback, close: do what? (I suppose nothing)
>> > >> > > > > > > > >> >
>> > >> > > > > > > > >> > Also you assume that after commit/rollback we may
>> > need
>> > >> to
>> > >> > > free
>> > >> > > > > > some
>> > >> > > > > > > > >> > resources on server node(s)or just do on client
>> > started
>> > >> > TX?
>> > >> > > > > > > > >> >
>> > >> > > > > > > > >> >
>> > >> > > > > > > > >> >
>> > >> > > > > > > > >> > On Tue, Mar 26, 2019 at 10:41 PM Alex Plehanov <
>> > >> > > > > > > > plehanov.alex@gmail.com
>> > >> > > > > > > > >> >
>> > >> > > > > > > > >> > wrote:
>> > >> > > > > > > > >> >
>> > >> > > > > > > > >> > > Sergey, we have the close() method in the thick
>> > >> client,
>> > >> > > it's
>> > >> > > > > > > > behavior
>> > >> > > > > > > > >> is
>> > >> > > > > > > > >> > > slightly different than rollback() method (it
>> > should
>> > >> > > > rollback
>> > >> > > > > if
>> > >> > > > > > > the
>> > >> > > > > > > > >> > > transaction is not committed and do nothing if
>> the
>> > >> > > > transaction
>> > >> > > > > > is
>> > >> > > > > > > > >> already
>> > >> > > > > > > > >> > > committed). I think we should support
>> > >> try-with-resource
>> > >> > > > > > semantics
>> > >> > > > > > > in
>> > >> > > > > > > > >> the
>> > >> > > > > > > > >> > > thin client and OP_TX_CLOSE will be useful here.
>> > >> > > > > > > > >> > >
>> > >> > > > > > > > >> > > Nikolay, suspend/resume didn't work yet for
>> > >> pessimistic
>> > >> > > > > > > > transactions.
>> > >> > > > > > > > >> > Also,
>> > >> > > > > > > > >> > > the main goal of suspend/resume operations is to
>> > >> support
>> > >> > > > > > > transaction
>> > >> > > > > > > > >> > > passing between threads. In the thin client, the
>> > >> > > transaction
>> > >> > > > > is
>> > >> > > > > > > > bound
>> > >> > > > > > > > >> to
>> > >> > > > > > > > >> > > the client connection, not client thread. I
>> think
>> > >> > passing
>> > >> > > a
>> > >> > > > > > > > >> transaction
>> > >> > > > > > > > >> > > between different client connections is not a
>> very
>> > >> > useful
>> > >> > > > > case.
>> > >> > > > > > > > >> > >
>> > >> > > > > > > > >> > > вт, 26 мар. 2019 г. в 22:17, Nikolay Izhikov <
>> > >> > > > > > nizhikov@apache.org
>> > >> > > > > > > >:
>> > >> > > > > > > > >> > >
>> > >> > > > > > > > >> > > > Hello, Alex.
>> > >> > > > > > > > >> > > >
>> > >> > > > > > > > >> > > > We also have suspend and resume operations.
>> > >> > > > > > > > >> > > > I think we should support them
>> > >> > > > > > > > >> > > >
>> > >> > > > > > > > >> > > > вт, 26 марта 2019 г., 22:07 Sergey Kozlov <
>> > >> > > > > > skozlov@gridgain.com
>> > >> > > > > > > >:
>> > >> > > > > > > > >> > > >
>> > >> > > > > > > > >> > > > > Hi
>> > >> > > > > > > > >> > > > >
>> > >> > > > > > > > >> > > > > Looks like I missed something but why we
>> need
>> > >> > > > OP_TX_CLOSE
>> > >> > > > > > > > >> operation?
>> > >> > > > > > > > >> > > > >
>> > >> > > > > > > > >> > > > > Also I suggest to reserve a code for
>> SAVEPOINT
>> > >> > > operation
>> > >> > > > > > which
>> > >> > > > > > > > >> very
>> > >> > > > > > > > >> > > > useful
>> > >> > > > > > > > >> > > > > to understand where transaction has been
>> rolled
>> > >> back
>> > >> > > > > > > > >> > > > >
>> > >> > > > > > > > >> > > > > On Tue, Mar 26, 2019 at 6:07 PM Alex
>> Plehanov <
>> > >> > > > > > > > >> > plehanov.alex@gmail.com
>> > >> > > > > > > > >> > > >
>> > >> > > > > > > > >> > > > > wrote:
>> > >> > > > > > > > >> > > > >
>> > >> > > > > > > > >> > > > > > Hello Igniters!
>> > >> > > > > > > > >> > > > > >
>> > >> > > > > > > > >> > > > > > I want to pick up the ticket IGNITE-7369
>> and
>> > >> add
>> > >> > > > > > > transactions
>> > >> > > > > > > > >> > support
>> > >> > > > > > > > >> > > > to
>> > >> > > > > > > > >> > > > > > our thin client implementation.
>> > >> > > > > > > > >> > > > > > I've looked at our current implementation
>> and
>> > >> have
>> > >> > > > some
>> > >> > > > > > > > >> proposals
>> > >> > > > > > > > >> > to
>> > >> > > > > > > > >> > > > > > support transactions:
>> > >> > > > > > > > >> > > > > >
>> > >> > > > > > > > >> > > > > > Add new operations to thin client
>> protocol:
>> > >> > > > > > > > >> > > > > >
>> > >> > > > > > > > >> > > > > >     OP_TX_GET, 4000, Get current
>> transaction
>> > >> for
>> > >> > > > client
>> > >> > > > > > > > >> connection
>> > >> > > > > > > > >> > > > > >     OP_TX_START, 4001, Start a new
>> > transaction
>> > >> > > > > > > > >> > > > > >     OP_TX_COMMIT, 4002, Commit transaction
>> > >> > > > > > > > >> > > > > >     OP_TX_ROLLBACK, 4003, Rollback
>> > transaction
>> > >> > > > > > > > >> > > > > >     OP_TX_CLOSE, 4004, Close transaction
>> > >> > > > > > > > >> > > > > >
>> > >> > > > > > > > >> > > > > > From the client side (java) new interfaces
>> > >> will be
>> > >> > > > > added:
>> > >> > > > > > > > >> > > > > >
>> > >> > > > > > > > >> > > > > > public interface ClientTransactions {
>> > >> > > > > > > > >> > > > > >     public ClientTransaction txStart();
>> > >> > > > > > > > >> > > > > >     public ClientTransaction
>> > >> > > > > > txStart(TransactionConcurrency
>> > >> > > > > > > > >> > > > concurrency,
>> > >> > > > > > > > >> > > > > > TransactionIsolation isolation);
>> > >> > > > > > > > >> > > > > >     public ClientTransaction
>> > >> > > > > > txStart(TransactionConcurrency
>> > >> > > > > > > > >> > > > concurrency,
>> > >> > > > > > > > >> > > > > > TransactionIsolation isolation, long
>> timeout,
>> > >> int
>> > >> > > > > txSize);
>> > >> > > > > > > > >> > > > > >     public ClientTransaction tx(); // Get
>> > >> current
>> > >> > > > > > connection
>> > >> > > > > > > > >> > > > transaction
>> > >> > > > > > > > >> > > > > >     public ClientTransactions
>> > withLabel(String
>> > >> > lb);
>> > >> > > > > > > > >> > > > > > }
>> > >> > > > > > > > >> > > > > >
>> > >> > > > > > > > >> > > > > > public interface ClientTransaction extends
>> > >> > > > > AutoCloseable {
>> > >> > > > > > > > >> > > > > >     public IgniteUuid xid(); // Do we need
>> > it?
>> > >> > > > > > > > >> > > > > >     public TransactionIsolation
>> isolation();
>> > >> > > > > > > > >> > > > > >     public TransactionConcurrency
>> > >> concurrency();
>> > >> > > > > > > > >> > > > > >     public long timeout();
>> > >> > > > > > > > >> > > > > >     public String label();
>> > >> > > > > > > > >> > > > > >
>> > >> > > > > > > > >> > > > > >     public void commit();
>> > >> > > > > > > > >> > > > > >     public void rollback();
>> > >> > > > > > > > >> > > > > >     public void close();
>> > >> > > > > > > > >> > > > > > }
>> > >> > > > > > > > >> > > > > >
>> > >> > > > > > > > >> > > > > > From the server side, I think as a first
>> step
>> > >> > (while
>> > >> > > > > > > > >> transactions
>> > >> > > > > > > > >> > > > > > suspend/resume is not fully implemented)
>> we
>> > can
>> > >> > use
>> > >> > > > the
>> > >> > > > > > same
>> > >> > > > > > > > >> > approach
>> > >> > > > > > > > >> > > > as
>> > >> > > > > > > > >> > > > > > for JDBC: add a new worker to each
>> > >> > > > ClientRequestHandler
>> > >> > > > > > and
>> > >> > > > > > > > >> process
>> > >> > > > > > > > >> > > > > > requests by this worker if the
>> transaction is
>> > >> > > started
>> > >> > > > > > > > >> explicitly.
>> > >> > > > > > > > >> > > > > > ClientRequestHandler is bound to client
>> > >> > connection,
>> > >> > > so
>> > >> > > > > > there
>> > >> > > > > > > > >> will
>> > >> > > > > > > > >> > be
>> > >> > > > > > > > >> > > > 1:1
>> > >> > > > > > > > >> > > > > > relation between client connection and
>> > thread,
>> > >> > which
>> > >> > > > > > process
>> > >> > > > > > > > >> > > operations
>> > >> > > > > > > > >> > > > > in
>> > >> > > > > > > > >> > > > > > a transaction.
>> > >> > > > > > > > >> > > > > >
>> > >> > > > > > > > >> > > > > > Also, there is a couple of issues I want
>> to
>> > >> > discuss:
>> > >> > > > > > > > >> > > > > >
>> > >> > > > > > > > >> > > > > > We have overloaded method txStart with a
>> > >> different
>> > >> > > set
>> > >> > > > > of
>> > >> > > > > > > > >> > arguments.
>> > >> > > > > > > > >> > > > Some
>> > >> > > > > > > > >> > > > > > of the arguments may be missing. To pass
>> > >> arguments
>> > >> > > > with
>> > >> > > > > > > > >> OP_TX_START
>> > >> > > > > > > > >> > > > > > operation we have the next options:
>> > >> > > > > > > > >> > > > > >  * Serialize full set of arguments and use
>> > some
>> > >> > > value
>> > >> > > > > for
>> > >> > > > > > > > >> missing
>> > >> > > > > > > > >> > > > > > arguments. For example -1 for int/long
>> types
>> > >> and
>> > >> > > null
>> > >> > > > > for
>> > >> > > > > > > > string
>> > >> > > > > > > > >> > > type.
>> > >> > > > > > > > >> > > > We
>> > >> > > > > > > > >> > > > > > can't use 0 for int/long types since 0
>> it's a
>> > >> > valid
>> > >> > > > > value
>> > >> > > > > > > for
>> > >> > > > > > > > >> > > > > concurrency,
>> > >> > > > > > > > >> > > > > > isolation and timeout arguments.
>> > >> > > > > > > > >> > > > > >  * Serialize arguments as a collection of
>> > >> > > > property-value
>> > >> > > > > > > pairs
>> > >> > > > > > > > >> > (like
>> > >> > > > > > > > >> > > > it's
>> > >> > > > > > > > >> > > > > > implemented now for CacheConfiguration).
>> In
>> > >> this
>> > >> > > case
>> > >> > > > > only
>> > >> > > > > > > > >> > explicitly
>> > >> > > > > > > > >> > > > > > provided arguments will be serialized.
>> > >> > > > > > > > >> > > > > > Which way is better? The simplest
>> solution is
>> > >> to
>> > >> > use
>> > >> > > > the
>> > >> > > > > > > first
>> > >> > > > > > > > >> > option
>> > >> > > > > > > > >> > > > > and I
>> > >> > > > > > > > >> > > > > > want to use it if there were no
>> objections.
>> > >> > > > > > > > >> > > > > >
>> > >> > > > > > > > >> > > > > > Do we need transaction id (xid) on the
>> client
>> > >> > side?
>> > >> > > > > > > > >> > > > > > If yes, we can pass xid along with
>> > >> OP_TX_COMMIT,
>> > >> > > > > > > > OP_TX_ROLLBACK,
>> > >> > > > > > > > >> > > > > > OP_TX_CLOSE operations back to the server
>> and
>> > >> do
>> > >> > > > > > additional
>> > >> > > > > > > > >> check
>> > >> > > > > > > > >> > on
>> > >> > > > > > > > >> > > > the
>> > >> > > > > > > > >> > > > > > server side (current transaction id for
>> > >> connection
>> > >> > > ==
>> > >> > > > > > > > >> transaction
>> > >> > > > > > > > >> > id
>> > >> > > > > > > > >> > > > > passed
>> > >> > > > > > > > >> > > > > > from client side). This, perhaps, will
>> > protect
>> > >> > > clients
>> > >> > > > > > > against
>> > >> > > > > > > > >> some
>> > >> > > > > > > > >> > > > > errors
>> > >> > > > > > > > >> > > > > > (for example when client try to commit
>> > outdated
>> > >> > > > > > > transaction).
>> > >> > > > > > > > >> But
>> > >> > > > > > > > >> > > > > > currently, we don't have data type
>> IgniteUuid
>> > >> in
>> > >> > > thin
>> > >> > > > > > client
>> > >> > > > > > > > >> > > protocol.
>> > >> > > > > > > > >> > > > Do
>> > >> > > > > > > > >> > > > > > we need to add it too?
>> > >> > > > > > > > >> > > > > > Also, we can pass xid as a string just to
>> > >> inform
>> > >> > the
>> > >> > > > > > client
>> > >> > > > > > > > and
>> > >> > > > > > > > >> do
>> > >> > > > > > > > >> > > not
>> > >> > > > > > > > >> > > > > pass
>> > >> > > > > > > > >> > > > > > it back to the server with commit/rollback
>> > >> > > operation.
>> > >> > > > > > > > >> > > > > > Or not to pass xid at all (.NET thick
>> client
>> > >> works
>> > >> > > > this
>> > >> > > > > > way
>> > >> > > > > > > as
>> > >> > > > > > > > >> far
>> > >> > > > > > > > >> > > as I
>> > >> > > > > > > > >> > > > > > know).
>> > >> > > > > > > > >> > > > > >
>> > >> > > > > > > > >> > > > > > What do you think?
>> > >> > > > > > > > >> > > > > >
>> > >> > > > > > > > >> > > > > > ср, 7 мар. 2018 г. в 16:22, Vladimir
>> Ozerov <
>> > >> > > > > > > > >> vozerov@gridgain.com
>> > >> > > > > > > > >> > >:
>> > >> > > > > > > > >> > > > > >
>> > >> > > > > > > > >> > > > > > > We already have transactions support in
>> > JDBC
>> > >> > > driver
>> > >> > > > in
>> > >> > > > > > TX
>> > >> > > > > > > > SQL
>> > >> > > > > > > > >> > > branch
>> > >> > > > > > > > >> > > > > > > (ignite-4191). Currently it is
>> implemented
>> > >> > through
>> > >> > > > > > > separate
>> > >> > > > > > > > >> > thread,
>> > >> > > > > > > > >> > > > > which
>> > >> > > > > > > > >> > > > > > > is not that efficient. Ideally we need
>> to
>> > >> finish
>> > >> > > > > > > decoupling
>> > >> > > > > > > > >> > > > > transactions
>> > >> > > > > > > > >> > > > > > > from threads. But alternatively we can
>> > change
>> > >> > the
>> > >> > > > > logic
>> > >> > > > > > on
>> > >> > > > > > > > >> how we
>> > >> > > > > > > > >> > > > > assign
>> > >> > > > > > > > >> > > > > > > thread ID to specific transaction and
>> > >> > > "impersonate"
>> > >> > > > > thin
>> > >> > > > > > > > >> client
>> > >> > > > > > > > >> > > > worker
>> > >> > > > > > > > >> > > > > > > threads when serving requests from
>> multiple
>> > >> > users.
>> > >> > > > > > > > >> > > > > > >
>> > >> > > > > > > > >> > > > > > >
>> > >> > > > > > > > >> > > > > > >
>> > >> > > > > > > > >> > > > > > > On Tue, Mar 6, 2018 at 10:01 PM, Denis
>> > Magda
>> > >> <
>> > >> > > > > > > > >> dmagda@apache.org>
>> > >> > > > > > > > >> > > > > wrote:
>> > >> > > > > > > > >> > > > > > >
>> > >> > > > > > > > >> > > > > > > > Here is an original discussion with a
>> > >> > reference
>> > >> > > to
>> > >> > > > > the
>> > >> > > > > > > > JIRA
>> > >> > > > > > > > >> > > ticket:
>> > >> > > > > > > > >> > > > > > > >
>> > >> > > http://apache-ignite-developers.2346864.n4.nabble
>> > >> > > > .
>> > >> > > > > > > > >> > > > > > > >
>> > >> > > > > > > >
>> > com/Re-Transaction-operations-using-the-Ignite-Thin-Client-
>> > >> > > > > > > > >> > > > > > > > Protocol-td25914.html
>> > >> > > > > > > > >> > > > > > > >
>> > >> > > > > > > > >> > > > > > > > --
>> > >> > > > > > > > >> > > > > > > > Denis
>> > >> > > > > > > > >> > > > > > > >
>> > >> > > > > > > > >> > > > > > > > On Tue, Mar 6, 2018 at 9:18 AM,
>> Dmitriy
>> > >> > > Setrakyan
>> > >> > > > <
>> > >> > > > > > > > >> > > > > > dsetrakyan@apache.org
>> > >> > > > > > > > >> > > > > > > >
>> > >> > > > > > > > >> > > > > > > > wrote:
>> > >> > > > > > > > >> > > > > > > >
>> > >> > > > > > > > >> > > > > > > > > Hi Dmitriy. I don't think we have a
>> > >> design
>> > >> > > > > proposal
>> > >> > > > > > > for
>> > >> > > > > > > > >> > > > transaction
>> > >> > > > > > > > >> > > > > > > > support
>> > >> > > > > > > > >> > > > > > > > > in thin clients. Do you mind taking
>> > this
>> > >> > > > > initiative
>> > >> > > > > > > and
>> > >> > > > > > > > >> > > creating
>> > >> > > > > > > > >> > > > an
>> > >> > > > > > > > >> > > > > > IEP
>> > >> > > > > > > > >> > > > > > > > on
>> > >> > > > > > > > >> > > > > > > > > Wiki?
>> > >> > > > > > > > >> > > > > > > > >
>> > >> > > > > > > > >> > > > > > > > > D.
>> > >> > > > > > > > >> > > > > > > > >
>> > >> > > > > > > > >> > > > > > > > > On Tue, Mar 6, 2018 at 8:46 AM,
>> Dmitriy
>> > >> > > > > Govorukhin <
>> > >> > > > > > > > >> > > > > > > > > dmitriy.govorukhin@gmail.com>
>> wrote:
>> > >> > > > > > > > >> > > > > > > > >
>> > >> > > > > > > > >> > > > > > > > > > Hi, Igniters.
>> > >> > > > > > > > >> > > > > > > > > >
>> > >> > > > > > > > >> > > > > > > > > > I've seen a lot of discussions
>> about
>> > >> thin
>> > >> > > > client
>> > >> > > > > > and
>> > >> > > > > > > > >> binary
>> > >> > > > > > > > >> > > > > > protocol,
>> > >> > > > > > > > >> > > > > > > > > but I
>> > >> > > > > > > > >> > > > > > > > > > did not hear anything about
>> > >> transactions
>> > >> > > > > support.
>> > >> > > > > > Do
>> > >> > > > > > > > we
>> > >> > > > > > > > >> > have
>> > >> > > > > > > > >> > > > some
>> > >> > > > > > > > >> > > > > > > draft
>> > >> > > > > > > > >> > > > > > > > > for
>> > >> > > > > > > > >> > > > > > > > > > this purpose?
>> > >> > > > > > > > >> > > > > > > > > >
>> > >> > > > > > > > >> > > > > > > > > > As I understand we have several
>> > >> problems:
>> > >> > > > > > > > >> > > > > > > > > >
>> > >> > > > > > > > >> > > > > > > > > >    - thread and transaction have
>> hard
>> > >> > > related
>> > >> > > > > (we
>> > >> > > > > > > use
>> > >> > > > > > > > >> > > > > thread-local
>> > >> > > > > > > > >> > > > > > > > > variable
>> > >> > > > > > > > >> > > > > > > > > >    and thread name)
>> > >> > > > > > > > >> > > > > > > > > >    - we can process only one
>> > >> transaction
>> > >> > at
>> > >> > > > the
>> > >> > > > > > same
>> > >> > > > > > > > >> time
>> > >> > > > > > > > >> > in
>> > >> > > > > > > > >> > > > one
>> > >> > > > > > > > >> > > > > > > thread
>> > >> > > > > > > > >> > > > > > > > > (it
>> > >> > > > > > > > >> > > > > > > > > >    mean we need hold thread per
>> > >> client. If
>> > >> > > > > connect
>> > >> > > > > > > 100
>> > >> > > > > > > > >> thin
>> > >> > > > > > > > >> > > > > clients
>> > >> > > > > > > > >> > > > > > > to
>> > >> > > > > > > > >> > > > > > > > 1
>> > >> > > > > > > > >> > > > > > > > > >    server node, then need to hold
>> 100
>> > >> > thread
>> > >> > > > on
>> > >> > > > > > the
>> > >> > > > > > > > >> server
>> > >> > > > > > > > >> > > > side)
>> > >> > > > > > > > >> > > > > > > > > >
>> > >> > > > > > > > >> > > > > > > > > > Let's discuss how we can implement
>> > >> > > > transactions
>> > >> > > > > > for
>> > >> > > > > > > > the
>> > >> > > > > > > > >> > thin
>> > >> > > > > > > > >> > > > > > client.
>> > >> > > > > > > > >> > > > > > > > > >
>> > >> > > > > > > > >> > > > > > > > >
>> > >> > > > > > > > >> > > > > > > >
>> > >> > > > > > > > >> > > > > > >
>> > >> > > > > > > > >> > > > > >
>> > >> > > > > > > > >> > > > >
>> > >> > > > > > > > >> > > > >
>> > >> > > > > > > > >> > > > > --
>> > >> > > > > > > > >> > > > > Sergey Kozlov
>> > >> > > > > > > > >> > > > > GridGain Systems
>> > >> > > > > > > > >> > > > > www.gridgain.com
>> > >> > > > > > > > >> > > > >
>> > >> > > > > > > > >> > > >
>> > >> > > > > > > > >> > >
>> > >> > > > > > > > >> >
>> > >> > > > > > > > >> >
>> > >> > > > > > > > >> > --
>> > >> > > > > > > > >> > Sergey Kozlov
>> > >> > > > > > > > >> > GridGain Systems
>> > >> > > > > > > > >> > www.gridgain.com
>> > >> > > > > > > > >> >
>> > >> > > > > > > > >>
>> > >> > > > > > > > >
>> > >> > > > > > > >
>> > >> > > > > > >
>> > >> > > > > >
>> > >> > > > >
>> > >> > > >
>> > >> > >
>> > >> >
>> > >>
>> > >
>> >
>>
>

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