Sure:
package com.footnote.tools.cassandra;
import com.datastax.driver.core.Cluster;
import com.datastax.driver.core.Cluster.Builder;
import com.datastax.driver.core.Session;
public class Test
{
public static void main(String[] args)
{
try
{
Builder builder = Cluster.builder();
Cluster c =
builder.addContactPoint("cas121.devf3.com").withPort(9042).build();
Session s = c.connect("rwille");
s.execute("select rhpath from browse_document_tree");
s.shutdown();
}
catch (Exception e)
{
e.printStackTrace();
}
System.exit(0);
}
}
Running this program occasionally produces the following output:
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in
[jar:file:/Users/rwille/.m2/repository/org/slf4j/slf4j-log4j12/1.6.1/slf4j-l
og4j12-1.6.1.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in
[jar:file:/Users/rwille/workspace_fold3/dev-backend/extern/slf4j-log4j12-1.6
.1.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an
explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
- Cannot find LZ4 class, you should make sure the LZ4 library is in the
classpath if you intend to use it. LZ4 compression will not be available for
the protocol.
- [Control connection] Cannot connect to any host, scheduling retry
com.datastax.driver.core.exceptions.NoHostAvailableException: All host(s)
tried for query failed (no host was tried)
at
com.datastax.driver.core.exceptions.NoHostAvailableException.copy(NoHostAvai
lableException.java:64)
at
com.datastax.driver.core.ResultSetFuture.extractCauseFromExecutionException(
ResultSetFuture.java:271)
at com.datastax.driver.core.Session$Manager.setKeyspace(Session.java:461)
at com.datastax.driver.core.Cluster.connect(Cluster.java:178)
at com.footnote.tools.cassandra.Test.main(Test.java:17)
Caused by: com.datastax.driver.core.exceptions.NoHostAvailableException: All
host(s) tried for query failed (no host was tried)
at
com.datastax.driver.core.RequestHandler.sendRequest(RequestHandler.java:96)
at com.datastax.driver.core.Session$Manager.execute(Session.java:513)
at com.datastax.driver.core.Session$Manager.executeQuery(Session.java:549)
at com.datastax.driver.core.Session$Manager.setKeyspace(Session.java:455)
... 2 more
It isn't very often that it fails. I had to run it about 20 times before it
got an error. However, because I cannot truncate, I have resorted to
dropping and recreating my schema for every unit test. I often have a random
test case fail with this same error.
The inability to truncate is actually my bigger problem. If I could truncate
tables, then I wouldn't have to create so many sessions, and the frequency
of this error would be at tolerable levels.
Thanks in advance.
Robert
From: "Turi, Ferenc (GE Power & Water, Non-GE)" <[email protected]>
Reply-To: <[email protected]>
Date: Thursday, November 21, 2013 12:26 PM
To: "[email protected]" <[email protected]>
Subject: RE: Intermittent connection error
Hi,
Please attach the source to have deeper look at it.
Ferenc
From: Robert Wille [mailto:[email protected]]
Sent: Thursday, November 21, 2013 7:11 PM
To: [email protected]
Subject: Intermittent connection error
I intermittently get the following error when I try to execute my first
query after connecting:
Caused by: com.datastax.driver.core.exceptions.NoHostAvailableException: All
host(s) tried for query failed (no host was tried)
at
com.datastax.driver.core.exceptions.NoHostAvailableException.copy(NoHostAvai
lableException.java:64)
at
com.datastax.driver.core.ResultSetFuture.extractCauseFromExecutionException(
ResultSetFuture.java:271)
at
com.datastax.driver.core.ResultSetFuture.getUninterruptibly(ResultSetFuture.
java:187)
at com.datastax.driver.core.Session.execute(Session.java:126)
at com.datastax.driver.core.Session.execute(Session.java:77)
The odd part is the "(no host was tried)". I definitely have provided it
with a host, since this exact same code works most of the time.
I don't know if this might be related to a question I posted earlier, which
I haven't been able to resolve yet. Whenever I issue a truncate command, I
get the error "Unable to complete request: one or more nodes were
unavailable".
I've got a single node with all empty tables. It is definitely up and
available, since most of the time I can connect and do stuff (except
truncate, which I can never do).
The only thing in the logs that looks relevant is this:
INFO [HANDSHAKE-/192.168.98.121] 2013-11-20 11:36:59,064
OutboundTcpConnection.java (line 386) Handshaking version with
/192.168.98.121
INFO [HANDSHAKE-/192.168.98.121] 2013-11-20 11:37:04,064
OutboundTcpConnection.java (line 395) Cannot handshake version with
/192.168.98.121
I'm running Cassandra 2.0.2.
Any help would be most appreciated.
Thanks
Robert
