http://www.datastax.com/support-forums/tags/jdbc Software, Support, and Training for Apache Cassandra en-US Wed, 19 Jun 2013 06:48:47 +0000 http://bbpress.org/?v=1.0.3 q http://www.datastax.com/support-forums/search.php http://www.datastax.com/support-forums/topic/jdbc-interaction-with-cassandra#post-4420 Tue, 31 Jul 2012 14:00:47 +0000 thepaul 4420@http://www.datastax.com/support-forums/ <p>That's right, the client software must be able to reconnect to a different node if the coordinator goes down. Ideally the CQL driver or other Cassandra connector library would take care of that for you, but not all of them do yet. </p> http://www.datastax.com/support-forums/topic/jdbc-interaction-with-cassandra#post-4394 Tue, 31 Jul 2012 08:26:01 +0000 hardikupadhyay 4394@http://www.datastax.com/support-forums/ <p>I want to understand that how cassandra ensures high availability. What i know is when we query casssandra database for data, a node called coordinator route the query to the appropriate cassandra node in the cluster with the required data. But what if the node which we specify in JDBC connection URL (Which i think will act as coordinator in the cluster, please make me correct if i am wrong) itself down? In this case how come cassandra ensures high availability?</p> <p>Perhaps we as a developer must provide fallback mechanism for that?</p> <p>Please help me out to understand this. </p> http://www.datastax.com/support-forums/topic/jdbc-interaction-with-cassandra#post-3961 Fri, 27 Jul 2012 09:03:30 +0000 xedin 3961@http://www.datastax.com/support-forums/ <p>I don't know about JDBC but if you want to insert columns that you don't have in your schema you can use Thrift which allows that for sure. </p> http://www.datastax.com/support-forums/topic/jdbc-interaction-with-cassandra#post-3943 Fri, 27 Jul 2012 05:31:56 +0000 hardikupadhyay 3943@http://www.datastax.com/support-forums/ <p>Thanks for the reply, one more thing which i like to know is ,can i insert different columns which i have not specified in schema definition?</p> <p>Because i tried , and it failed. </p> http://www.datastax.com/support-forums/topic/jdbc-interaction-with-cassandra#post-3841 Thu, 26 Jul 2012 09:32:25 +0000 xedin 3841@http://www.datastax.com/support-forums/ <p>Yes, you need to create your schema before using JDBC. </p> http://www.datastax.com/support-forums/topic/jdbc-interaction-with-cassandra#post-3809 Thu, 26 Jul 2012 05:15:30 +0000 hardikupadhyay 3809@http://www.datastax.com/support-forums/ <p>Hi,<br /> I want to know<br /> Does JDBC needs predefined cassandra column family structure?<br /> Means should i create column family schema prior to inserting data into column family<br /> via JDBC? </p> http://www.datastax.com/support-forums/topic/jdbc-pool-eating-connections-when-using-thrift-server#post-914 Thu, 22 Dec 2011 13:28:59 +0000 Marius Waldal 914@http://www.datastax.com/support-forums/ <p>We have switched communication from a local cassandra to a dev server now, and here the problem is only when using JDBC connections against cassandra. If we switch to Hector, the problem does not persist.</p> <p>We have decided, for now, to stick with Hector for the connections from the Thrift server and use JDBC for Core operations. We will return to the JDBC issues after the system is live using Hector and everything works well. </p> http://www.datastax.com/support-forums/topic/jdbc-pool-eating-connections-when-using-thrift-server#post-880 Tue, 20 Dec 2011 16:23:58 +0000 zznate 880@http://www.datastax.com/support-forums/ <p>If I am reading that correctly, every time you invoke GenericObjectPool#borrowObject you are creating a new socket instead of returning an existing socket from the pool. Is GOP#releaseObject invoked with the socket when the connection usage is finished?</p> <p>This really just sounds like a misunderstanding with the commons-pooling API. I would suggest a look at DBCP in commons (which uses commons pooling for vanilla JDBC usage for some extra examples with a similar use case. </p> http://www.datastax.com/support-forums/topic/jdbc-pool-eating-connections-when-using-thrift-server#post-877 Tue, 20 Dec 2011 07:51:20 +0000 Marius Waldal 877@http://www.datastax.com/support-forums/ <p>The TSocket is wrapped by TTransport. The socket is created like this:</p> <p><code><br /> TTransport createTSocket(final String host, final int port) {<br /> final TSocket tsocket = new TSocket(host, port, socketTimeout);<br /> try {<br /> tsocket.getSocket().setKeepAlive(false);<br /> } catch (SocketException ex) {<br /> logger.warn("failed to disable keepalive");<br /> }<br /> return tsocket; }<br /> </code></p> <p>This is done inside TSocketFactory; a class creating TSockets based on a UriManager for managing multiple hosts, and the makeObject() method here is used by GenericObjectPool.borrowObject()</p> <p>Was this answering your question?</p> <p>Thanks for the sidenote. I will take this up with our other developers. And looking forward to the jdbc-conn-pool ! </p> http://www.datastax.com/support-forums/topic/jdbc-pool-eating-connections-when-using-thrift-server#post-872 Mon, 19 Dec 2011 21:20:51 +0000 zznate 872@http://www.datastax.com/support-forums/ <p>How are you constructing the underlying TSocket implementation and with which Transport (if any) are you wrapping said TSocket?</p> <p>ie. the call to DataSource#getConnection() should hit a pool who's contents have been constructed thusly:</p> <p> ttps://github.com/rantav/hector/blob/master/core/src/main/java/me/prettyprint/cassandra/connection/client/HThriftClient.java#L123-146</p> <p>Side note: after extensive testing in hector over a year ago, we *ripped out* commons pooling due to poor concurrency characteristics with lots of threads. YMMV though, as we had specific general-purpose targets for which we were aiming.</p> <p>Oh, it's not quite ready for prime-time, but we will be offering <a href="https://github.com/riptano/jdbc-conn-pool" rel="nofollow">https://github.com/riptano/jdbc-conn-pool</a> shortly. </p> http://www.datastax.com/support-forums/topic/jdbc-pool-eating-connections-when-using-thrift-server#post-871 Mon, 19 Dec 2011 21:05:33 +0000 Marius Waldal 871@http://www.datastax.com/support-forums/ <p>@zznate Thanks for answering.</p> <p>The TServer is not managing the connections itself. It uses our Core module, which has a Spring-configured datasource that extends org.apache.tomcat.jdbc.pool.DataSource.<br /> maxActive is set to 50, and we see during startup that this is read by the server. However, it seems that the connections are never returned when used by the server module, although this is not a problem when Core itself uses it for import and calculation.</p> <p>The TServer is using an org.apache.commons.pool.impl.GenericObjectPool for its workers, but as far as we can tell, this is not the pool that eats threads. </p> http://www.datastax.com/support-forums/topic/jdbc-pool-eating-connections-when-using-thrift-server#post-868 Mon, 19 Dec 2011 17:20:21 +0000 zznate 868@http://www.datastax.com/support-forums/ <p>What pooling library are you using?</p> <p>Do you have any examples of how you are using TServer to construct and manage connections? It sounds like you are just creating new connections instead of returning existing ones. I can't really speculate further than that without more information. </p> http://www.datastax.com/support-forums/topic/jdbc-pool-eating-connections-when-using-thrift-server#post-867 Mon, 19 Dec 2011 13:34:11 +0000 Marius Waldal 867@http://www.datastax.com/support-forums/ <p>Ok guys, we are at a loss here and hoping you may shed some light on this total show stopper!</p> <p>We are using CQL v. 1.0.5 and are experiencing problems using jdbc pooling from a thrift server.</p> <p>In our Core module, we have import jobs and calculation jobs using the thread pool without problems, reading and writing tens of thousands of records lightning fast.</p> <p>However; we are also using a Server module (based on org.apache.thrift.server.TServer) which is in turn using the same code from Core for connections to Cassandra. When we use this server, it seems connections are not released and reused, but the pool is constantly growing until reaching a roof at &lt;16.000 connections, after which we get a<br /> Error in thread "Thread-3"<br /> message on the server, and a timeout on the client.</p> <p>What beats us is why this works fine when running the import and calculation jobs, but not when the same dao classes are used from the server (imported as a maven artifact). </p> <p>Any ideas whatsoever would be greatly appreciated!</p> <p>Cheers<br /> Marius </p> http://www.datastax.com/support-forums/topic/connecting-to-brisk-hive-through-jdbc#post-208 Tue, 21 Jun 2011 11:13:03 +0000 john 208@http://www.datastax.com/support-forums/ <p>Allright, I got it working after all. The trick was that Hive was not running in the background at all (something I wrongfully assumed, assumption is the mother of all ... :) )</p> <p>Here's how to start the Hive server in order to be able to connect to it through JDBC:</p> <p>$ export HIVE_PORT=10000<br /> $ brisk hive --service hiveserver</p> <p>Good luck! </p> http://www.datastax.com/support-forums/topic/connecting-to-brisk-hive-through-jdbc#post-207 Tue, 21 Jun 2011 10:58:16 +0000 john 207@http://www.datastax.com/support-forums/ <p>Some additional info:</p> <p>I tried connecting to all the ports the Brisk process is listening on, it did not succeed.</p> <p>Port: Found:<br /> -------------------------------<br /> 7000 &lt;failed, connection refused&gt;<br /> 7199 &lt;failed, java.sql.SQLException: org.apache.thrift.transport.TTransportException&gt;<br /> 8012 &lt;failed, java.sql.SQLException: org.apache.thrift.transport.TTransportException&gt;<br /> 8081 JMX Management Console (HTTP)<br /> 9160 cassandra<br /> 9260 &lt;failed, connection refused&gt;<br /> 36141 &lt;failed, java.sql.SQLException: org.apache.thrift.transport.TTransportException&gt;<br /> 49854 Hadoop<br /> 50030 Hadoop Map/Reduce Administration (HTTP)<br /> 50060 Hadoop Task Tracker (HTTP)<br /> 54268 &lt;failed, connection refused&gt;<br /> 58522 &lt;failed, java.sql.SQLException: org.apache.thrift.transport.TTransportException&gt;<br /> 60539 &lt;failed, connection refused&gt; </p>