> If we use new approach, we can reduce this timeout. But this can affect old clients.
idleTimeout is disabled by default, we are not going to change this. > Also, let's think about that sending heartbeats and interval of sending > heartbeats could be calculated on the server side (i.e. one third of idle > timeout) and sent to the client during handshake. > Also we can introduce something like a negotiation mechanism as in > zookeeper. I tend to agree with Maksim here, let's keep it simple and explicit. Log a warning, but don't do anything clever. On Mon, Feb 7, 2022 at 6:15 PM Ivan Daschinsky <ivanda...@gmail.com> wrote: > >> idleTimeout already exists, I don't think we should change the way it > works (or did I misunderstand you?) > If we use new approach, we can reduce this timeout. But this can affect old > clients. > > > Also, let's think about that sending heartbeats and interval of sending > heartbeats could be calculated on the server side (i.e. one third of idle > timeout) and sent to the client > during handshake. > Also we can introduce something like a negotiation mechanism as in > zookeeper. > > > пн, 7 февр. 2022 г. в 18:05, Pavel Tupitsyn <ptupit...@apache.org>: > > > Igor, > > > > > Maybe clients should pass this information on to the handshake. > > > > Do you think we should log a mismatched timeout warning on the server, > not > > on the client? > > Or should we do both? > > > > > > I've updated the proposal with OP_GET_IDLE_TIMEOUT and some other details > > discussed above. > > > > On Mon, Feb 7, 2022 at 5:42 PM Igor Sapego <isap...@apache.org> wrote: > > > > > Feature seems useful for me as it makes connection management more > robust > > > and > > > predictable. > > > > > > I agree with Pavel, that we should print warning when heartbeat period > is > > > larger than > > > idle timeout, but I see a problem here as idle timeout is configured on > > > server and is not > > > known to clients, while heartbeats configured on clients and their > period > > > is not known > > > to the server. Maybe clients should pass this information on to the > > > handshake. > > > > > > Regarding Python and PHP clients - can not we use some kind of timers > to > > > implement > > > this feature? > > > > > > Best Regards, > > > Igor > > > > > > > > > On Mon, Feb 7, 2022 at 5:23 PM Pavel Tupitsyn <ptupit...@apache.org> > > > wrote: > > > > > > > Maksim, agree. Let's not be too clever and only log a warning. > > > > > > > > On Mon, Feb 7, 2022 at 5:23 PM Pavel Tupitsyn <ptupit...@apache.org> > > > > wrote: > > > > > > > > > Ivan, idleTimeout already exists, I don't think we should change > the > > > way > > > > > it works (or did I misunderstand you?) > > > > > > > > > > Of course, enabling heartbeats means that otherwise idle clients > will > > > no > > > > > longer be disconnected by the server. > > > > > I think we should cross-link those properties in the documentation > > and > > > > > explain this behavior. > > > > > > > > > > On Mon, Feb 7, 2022 at 4:39 PM Ivan Daschinsky < > ivanda...@gmail.com> > > > > > wrote: > > > > > > > > > >> >>3. Already implemented: when > > > ClientConnectorConfiguration#idleTimeout > > > > is > > > > >> not zero, server disconnects idle clients > > > > >> >> > > > > >> But I suppose it would be great to have: > > > > >> 1. If client supports keep alive, use idleTimeout > > > > >> 2. If not, do not use it. > > > > >> > > > > >> But I am not sure if it is correct or not. > > > > >> > > > > >> пн, 7 февр. 2022 г. в 16:01, Maksim Timonin < > > timoninma...@apache.org > > > >: > > > > >> > > > > >> > I believe explicit is better than implicit :) Also in case of > > > dynamic > > > > >> > calculation of timeout, it can change dynamically, for example > > > > >> restarting a > > > > >> > cluster with different configuration should reconfigure clients > > too. > > > > >> Looks > > > > >> > complicated. > > > > >> > > > > > >> > My vote for WARN + javadocs with mention of this issue. > > > > >> > > > > > >> > On Mon, Feb 7, 2022 at 3:51 PM Pavel Tupitsyn < > > ptupit...@apache.org > > > > > > > > >> > wrote: > > > > >> > > > > > >> > > > WDYT, should we add a WARN message for clients that > configure > > > > >> > > > keepAliveTimeout greater than idleTimeout on the server > side? > > > > >> > > > > > > >> > > I think we should either log a WARN, or retrieve idleTimeout > > from > > > > >> server > > > > >> > > and configure heartbeatTimeout accordingly (e.g. divide by 2). > > > > >> > > Thoughts? > > > > >> > > > > > > >> > > On Mon, Feb 7, 2022 at 3:14 PM Maksim Timonin < > > > > >> timoninma...@apache.org> > > > > >> > > wrote: > > > > >> > > > > > > >> > > > Hi Pavel, > > > > >> > > > > > > > >> > > > Thanks for the links. Yes, I forgot that the flag of changed > > > > >> topology > > > > >> > is > > > > >> > > > lazy. Also I missed that the keepAlive setting is configured > > on > > > > the > > > > >> > > client > > > > >> > > > side (alternatively to idleTimeout that is on the server > > side). > > > > >> > > > > > > > >> > > > Now I understand, this feature can be helpful then. Every > > client > > > > can > > > > >> > > > configure itself in case it's possible to be idle sometimes, > > and > > > > >> choose > > > > >> > > > an appropriate timeout by itself too. And by default the > > feature > > > > >> should > > > > >> > > be > > > > >> > > > disabled. > > > > >> > > > > > > > >> > > > WDYT, should we add a WARN message for clients that > configure > > > > >> > > > keepAliveTimeout greater than idleTimeout on the server > side? > > > > >> > > > > > > > >> > > > > > > > >> > > > > > > > >> > > > On Mon, Feb 7, 2022 at 1:05 PM Pavel Tupitsyn < > > > > ptupit...@apache.org > > > > >> > > > > > >> > > > wrote: > > > > >> > > > > > > > >> > > > > Ivan, > > > > >> > > > > > > > > >> > > > > I suggest the following: > > > > >> > > > > > > > > >> > > > > 1. Server sends KEEP_ALIVE feature flag, which means it > > > accepts > > > > >> > > > > OP_KEEP_ALIVE empty message > > > > >> > > > > 2. Client sends OP_KEEP_ALIVE when the connection is idle > > for > > > a > > > > >> > > > > certain period of time > > > > >> > > > > 3. Already implemented: when > > > > >> ClientConnectorConfiguration#idleTimeout > > > > >> > > is > > > > >> > > > > not zero, server disconnects idle clients > > > > >> > > > > > > > > >> > > > > This way we don't need server->client keepalives, as you > > > > correctly > > > > >> > > noted. > > > > >> > > > > > > > > >> > > > > On Mon, Feb 7, 2022 at 12:43 PM Ivan Daschinsky < > > > > >> ivanda...@gmail.com > > > > >> > > > > > > >> > > > > wrote: > > > > >> > > > > > > > > >> > > > > > Pavel, I suppose that ideally: > > > > >> > > > > > 1. Client send in handshake flag, that it supports > > > KEEP_ALIVE > > > > >> > feature > > > > >> > > > and > > > > >> > > > > > server takes it into account. > > > > >> > > > > > 2. Each request of client can be considered as > keep-alive > > > > ping. > > > > >> > > > > > 3. Client send failure should be processed using retry > > > policy. > > > > >> > > > > > 4. Server should not send keep-alive packets, it is > > > redundant, > > > > >> but > > > > >> > > > server > > > > >> > > > > > should track requests from client and if there is no > > > requests > > > > >> from > > > > >> > > > client > > > > >> > > > > > with KEEP_ALIVE feature, > > > > >> > > > > > automatically close connection and free resources. > > > > >> > > > > > > > > > >> > > > > > Similar approach is used in zookeeper clients. > > > > >> > > > > > > > > > >> > > > > > пн, 7 февр. 2022 г. в 12:24, Pavel Tupitsyn < > > > > >> ptupit...@apache.org > > > > >> > >: > > > > >> > > > > > > > > > >> > > > > > > Ivan, > > > > >> > > > > > > > > > > >> > > > > > > Ideally, the check should come from both sides. > > > > >> > > > > > > - Client periodically sends keepalive to server > > > > >> > > > > > > - Server periodically sends keepalive to client > > > > >> > > > > > > > > > > >> > > > > > > Feature flags will be added accordingly, so it is not > > > > >> necessary > > > > >> > to > > > > >> > > > > > > implement this in all thin clients. > > > > >> > > > > > > > > > > >> > > > > > > On Mon, Feb 7, 2022 at 11:43 AM Ivan Daschinsky < > > > > >> > > ivanda...@gmail.com > > > > >> > > > > > > > > >> > > > > > > wrote: > > > > >> > > > > > > > > > > >> > > > > > > > I suppose it is great idea, but this functionality > can > > > be > > > > >> hard > > > > >> > to > > > > >> > > > > > > implement > > > > >> > > > > > > > for some platforms. I.e. sync python client or php > > > (there > > > > >> is no > > > > >> > > > real > > > > >> > > > > > > > multithreading for python (GIL) and php is single > > > threaded > > > > >> by > > > > >> > > > > design). > > > > >> > > > > > > But > > > > >> > > > > > > > for async clients it is not very hard to implement. > > > > >> > Nevertheless, > > > > >> > > > > this > > > > >> > > > > > > > feature should be optional, because of possible > > > technical > > > > >> > > > > limitations. > > > > >> > > > > > > > > > > > >> > > > > > > > Pavel, is this check mostly for client side? Or > > servers > > > > can > > > > >> do > > > > >> > > some > > > > >> > > > > > > actions > > > > >> > > > > > > > if there is no activity from thin client (i.e. > closing > > > > >> context > > > > >> > > and > > > > >> > > > > free > > > > >> > > > > > > > resources such as queries' handles and so on?) > > > > >> > > > > > > > > > > > >> > > > > > > > пн, 7 февр. 2022 г. в 11:09, Pavel Tupitsyn < > > > > >> > > ptupit...@apache.org > > > > >> > > > >: > > > > >> > > > > > > > > > > > >> > > > > > > > > Hi Maksim, > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > half-state is a possible situation when an > Ignite > > > node > > > > >> goes > > > > >> > > > down > > > > >> > > > > or > > > > >> > > > > > > > > somehow removes connection to a thin client > > > > >> > > > > > > > > > > > > >> > > > > > > > > Half-open state is also possible when, for > example, > > an > > > > >> > > > intermediate > > > > >> > > > > > > > router > > > > >> > > > > > > > > is rebooted [1]. > > > > >> > > > > > > > > > > > > >> > > > > > > > > This is what we seem to have encountered with one > of > > > our > > > > >> > > > customers > > > > >> > > > > - > > > > >> > > > > > > they > > > > >> > > > > > > > > have a stable cluster, and long-living (multiple > > days) > > > > >> thin > > > > >> > > > client > > > > >> > > > > > > > > connections which can be idle for some time. > > > > >> > > > > > > > > And only when we send some data on such an idle > > > > >> connection do > > > > >> > > we > > > > >> > > > > > > discover > > > > >> > > > > > > > > that it is broken. > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > But with enabled (true by default) > > > partitionAwareness > > > > >> > feature > > > > >> > > > > > clients > > > > >> > > > > > > > can > > > > >> > > > > > > > > be notified about topology changes > > > > >> > > > > > > > > > > > > >> > > > > > > > > Partition awareness is a "lazy" notification in a > > form > > > > of > > > > >> a > > > > >> > > > > response > > > > >> > > > > > > > > message flag [2]. > > > > >> > > > > > > > > You won't get one on an idle connection. > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > the connections are removed on the server side > by > > > > client > > > > >> > idle > > > > >> > > > > > timeout > > > > >> > > > > > > > > > > > > >> > > > > > > > > Idle timeout is disabled by default. > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > is it OK to keep such connections alive for a > long > > > > time > > > > >> > > > > > > > > > > > > >> > > > > > > > > I think it is up to the user. > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > in the case of partition awareness features it > can > > > > lead > > > > >> to > > > > >> > > > > wasting > > > > >> > > > > > > TCP > > > > >> > > > > > > > > sockets on Ignite nodes, can't it > > > > >> > > > > > > > > > > > > >> > > > > > > > > Can you please elaborate? > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > [1] > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > > > > > > > https://blog.stephencleary.com/2009/05/detection-of-half-open-dropped.html > > > > >> > > > > > > > > [2] > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > > > > > > > https://cwiki.apache.org/confluence/display/IGNITE/IEP-23%3A+Best+Effort+Affinity+for+Thin+Clients > > > > >> > > > > > > > > > > > > >> > > > > > > > > On Fri, Feb 4, 2022 at 4:01 PM Maksim Timonin < > > > > >> > > > > > timoninma...@apache.org > > > > >> > > > > > > > > > > > >> > > > > > > > > wrote: > > > > >> > > > > > > > > > > > > >> > > > > > > > > > Hi Pavel, > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > Thanks for starting this thread! Can I ask some > > > > >> questions > > > > >> > > here > > > > >> > > > to > > > > >> > > > > > get > > > > >> > > > > > > > the > > > > >> > > > > > > > > > feature more clearly? > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > As I understand it correctly, half-state is a > > > possible > > > > >> > > > situation > > > > >> > > > > > when > > > > >> > > > > > > > an > > > > >> > > > > > > > > > Ignite node goes down or somehow removes > > connection > > > > to a > > > > >> > thin > > > > >> > > > > > client. > > > > >> > > > > > > > But > > > > >> > > > > > > > > > with enabled (true by default) > partitionAwareness > > > > >> feature > > > > >> > > > clients > > > > >> > > > > > can > > > > >> > > > > > > > be > > > > >> > > > > > > > > > notified about topology changes. So, there are > > > > possible > > > > >> > > cases: > > > > >> > > > > > > > > > 1. ThinClient connects to a single node. > > > > >> > > > > > > > > > 2. Ignite node removes connection from itself. > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > I like the idea for the case with a single node, > > as > > > it > > > > >> > helps > > > > >> > > > fail > > > > >> > > > > > > fast. > > > > >> > > > > > > > > > But is it OK to connect a client to a single > node > > > > only? > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > For the second one: you mention that a case for > > the > > > > >> second > > > > >> > > > option > > > > >> > > > > > is > > > > >> > > > > > > > > > "Long-living and mostly idle connections are > > > > especially > > > > >> > > > > susceptible > > > > >> > > > > > > to > > > > >> > > > > > > > > this > > > > >> > > > > > > > > > behavior". If I understand correctly the > > connections > > > > are > > > > >> > > > removed > > > > >> > > > > on > > > > >> > > > > > > the > > > > >> > > > > > > > > > server side by client idle timeout. Can we just > > > > >> configure > > > > >> > the > > > > >> > > > > idle > > > > >> > > > > > > > > timeout > > > > >> > > > > > > > > > for cases where we really need keeping alive > idle > > > > >> > > connections? > > > > >> > > > > Are > > > > >> > > > > > > > there > > > > >> > > > > > > > > > any other cases with unexpectedly dropped > > > connections? > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > I'm wondering is it OK to keep such connections > > > alive > > > > >> for a > > > > >> > > > long > > > > >> > > > > > > time? > > > > >> > > > > > > > > > Also in the case of partition awareness features > > it > > > > can > > > > >> > lead > > > > >> > > to > > > > >> > > > > > > wasting > > > > >> > > > > > > > > TCP > > > > >> > > > > > > > > > sockets on Ignite nodes, can't it? > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > Thanks! > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > On Thu, Feb 3, 2022 at 2:24 PM Pavel Tupitsyn < > > > > >> > > > > > ptupit...@apache.org> > > > > >> > > > > > > > > > wrote: > > > > >> > > > > > > > > > > > > > >> > > > > > > > > >> Igniters, > > > > >> > > > > > > > > >> > > > > >> > > > > > > > > >> Please review the proposal to add heartbeat > > > messages > > > > to > > > > >> > the > > > > >> > > > thin > > > > >> > > > > > > > client > > > > >> > > > > > > > > >> protocol (both 2.x and 3.x) and let me know > your > > > > >> thoughts: > > > > >> > > > > > > > > >> > > > > >> > > > > > > > > >> > > > > >> > > > > > > > > >> > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > > > > > > > https://cwiki.apache.org/confluence/display/IGNITE/IEP-83+Thin+Client+Keepalive > > > > >> > > > > > > > > >> > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > -- > > > > >> > > > > > > > Sincerely yours, Ivan Daschinskiy > > > > >> > > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > > >> > > > > > -- > > > > >> > > > > > Sincerely yours, Ivan Daschinskiy > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > > >> -- > > > > >> Sincerely yours, Ivan Daschinskiy > > > > >> > > > > > > > > > > > > > > > > > -- > Sincerely yours, Ivan Daschinskiy >
