It is also worth mentioning that client connections can be controlled (limited) on the server-side with the CacheServer.setMaxConnections(:int). [1] I am not sure this would help on the client though if you have a large number of Threads consuming connections from the Pool and attempting to reach the server, but would (should) help control resource utilization on the server if there are 1) a large number of busy clients 2) doing a bunch of concurrent work.
[1] https://geode.apache.org/releases/latest/javadoc/org/apache/geode/cache/server/CacheServer.html#setMaxConnections-int- On Tue, Jul 23, 2019 at 8:49 AM Jacob Barrett <jbarr...@pivotal.io> wrote: > What version of Geode are you using? > > I ask because on develop there is a yet to be release fix to connection > pooling for the Java client. The same fix has not been rolled out to the > C++ client. For version 1.9 and older if you are using lots of threads in > your client you will want to enable thread local connection pooling. > > Java: > https://geode.apache.org/releases/latest/javadoc/org/apache/geode/cache/client/PoolFactory.html#setThreadLocalConnections-boolean- > C++: > https://geode.apache.org/releases/latest/cppdocs/a00789.html#a62f037e2c91bc6869fafaad690040322 > > In both C++ and Java clients the creation of new connections is caused by > an exhausted pool. If you request a connection to a specific server, like > when doing single hop, if there are no connections currently in the pool > then a new connection is created. The apparent difference in Java and C++ > is likely caused by differences in lock contention in the pool. The Java > client had serious lock contention that keep utilization low, which is > fixed in develop (1.10). Thread local connections was an old attempt to > address this issue but resulted in lots of connections being idle in a > single-hop scenario. > > -Jake > > On Jul 23, 2019, at 7:39 AM, Alberto Gomez <alberto.go...@est.tech> wrote: > > Just a small correction on my original e-mail. > > When I said that "connections are closed because the server considered > them idle" I meant that "connections are closed because the client > library considered them idle". > > Best regards, > > Alberto > > On 23/7/19 14:48, Alberto Gomez wrote: > > Hi, > > I have run some tests using two different clients, a Java one and a C++ > one, both with single hop enabled, maxConnections not limited (set to > -1), accessing a partitioned region, and have observed the following: > > - If the amount of operations sent to the Geode cluster is not very > high, the number of connections from the client to the servers remains > constant and reasonably low (the number appears to be (number of threads > in the client * number of servers in the Geode cluster)). > > - If the amount of operations sent to the Geode cluster is very high > then the behavior seems different between the Java and the C++ client: > > * With the Java client, the number of connections seems to be > bounded to a maximum that seems to be (number of threads in the client * > number of servers) although there is a continuous thrashing of > connections (connections closed and opened continuously). According to > my observations, the reason why connections are closed is because the > server considers them idle. > > * With the C++ client, the number of connections seems to grow > indefinitely and quite quickly. In this case, the amount of connections > closed (if any) seems very small. This is a problem because sooner or > later the client runs out of file descriptors. > > I have some questions regarding the observed behavior: > > - What fires the creation of new connections in the Java case? Is there > a limit for the number of connections opened (there seems to be one)? > > - In the Java case, what could be causing that some connections are idle > given that the amount of operations sent is very high? > > - In the C++ case, what fires the creation of new connections? > > - In the C++, is it normal that the number of connections grows > indefinitely? > > - Is there a reason for the two client APIs to behave differently (in > the Java one connections expire while in the C++ connections do not > expire)? > > > Thanks in advance, > > Alberto > > > > -- -John john.blum10101 (skype)
