我正在使用在 AWS EMR 的 Apache Flink 上运行的 AWS Keyspace (Cassandra 3.11.2)。下面的查询有时会引发异常。AWS Lambda 上使用的相同代码也具有相同的异常 NoHost。我做错了什么？
String query = "INSERT INTO TEST (field1, field2) VALUES(?, ?)";
PreparedStatement prepared = CassandraConnector.prepare(query);
int i = 0;
BoundStatement bound = prepared.bind().setString(i++, "Field1").setString(i++, "Field2")
.setConsistencyLevel(ConsistencyLevel.LOCAL_QUORUM);
ResultSet rs = CassandraConnector.execute(bound);
at com.datastax.oss.driver.api.core.NoNodeAvailableException.copy(NoNodeAvailableException.java:40)
at com.datastax.oss.driver.internal.core.util.concurrent.CompletableFutures.getUninterruptibly(CompletableFutures.java:149)
at com.datastax.oss.driver.internal.core.cql.CqlRequestSyncProcessor.process(CqlRequestSyncProcessor.java:53)
at com.datastax.oss.driver.internal.core.cql.CqlRequestSyncProcessor.process(CqlRequestSyncProcessor.java:30)
at com.datastax.oss.driver.internal.core.session.DefaultSession.execute(DefaultSession.java:230)
at com.datastax.oss.driver.api.core.cql.SyncCqlSession.execute(SyncCqlSession.java:53)
at com.test.manager.connectors.CassandraConnector.execute(CassandraConnector.java:16)
at com.test.repository.impl.BackupRepositoryImpl.insert(BackupRepositoryImpl.java:36)
at com.test.service.impl.BackupServiceImpl.insert(BackupServiceImpl.java:18)
at com.test.flink.function.AsyncBackupFunction.processMessage(AsyncBackupFunction.java:78)
at com.test.flink.function.AsyncBackupFunction.lambda$asyncInvoke$0(AsyncBackupFunction.java:35)
at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1604)
at java.util.concurrent.CompletableFuture$AsyncSupply.exec(CompletableFuture.java:1596)
at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
这是我的代码：
CassandraConnector.java：因为 initpreparedStatement 的开销很大，所以我缓存了这个。
public class CassandraConnector {
private static final ConcurrentHashMap<String, PreparedStatement> preparedStatementCache = new ConcurrentHashMap<String, PreparedStatement>();
public static ResultSet execute(BoundStatement bound) {
CqlSession session = CassandraManager.getSessionInstance();
return session.execute(bound);
}
public static ResultSet execute(String query) {
CqlSession session = CassandraManager.getSessionInstance();
return session.execute(query);
}
public static PreparedStatement prepare(String query) {
PreparedStatement result = preparedStatementCache.get(query);
if (result == null) {
CqlSession session = CassandraManager.getSessionInstance();
result = session.prepare(query);
preparedStatementCache.putIfAbsent(query, result);
}
return result;
}
}
CassandraManager.java：我正在对会话对象使用单例双重检查锁定。
public class CassandraManager {
private static final Logger logger = LoggerFactory.getLogger(CassandraManager.class);
private static final String SSL_CASSANDRA_PASSWORD = "password";
private static volatile CqlSession session;
static {
try {
initSession();
} catch (Exception e) {
logger.error("Error CassandraManager getSessionInstance", e);
}
}
private static void initSession() {
List<InetSocketAddress> contactPoints = Collections.singletonList(InetSocketAddress.createUnresolved(
"cassandra.ap-southeast-1.amazonaws.com", 9142));
DriverConfigLoader loader = DriverConfigLoader.fromClasspath("application.conf");
Long start = BaseHelper.getTime();
session = CqlSession.builder().addContactPoints(contactPoints).withConfigLoader(loader)
.withAuthCredentials(AppUtil.getProperty("cassandra.username"),
AppUtil.getProperty("cassandra.password"))
.withSslContext(getSSLContext()).withLocalDatacenter("ap-southeast-1")
.withKeyspace(AppUtil.getProperty("cassandra.keyspace")).build();
logger.info("End connect: " + (new Date().getTime() - start));
}
public static CqlSession getSessionInstance() {
if (session == null || session.isClosed()) {
synchronized (CassandraManager.class) {
if (session == null || session.isClosed()) {
initSession();
}
}
}
return session;
}
public static SSLContext getSSLContext() {
InputStream in = null;
try {
KeyStore ks = KeyStore.getInstance("JKS");
in = CassandraManager.class.getClassLoader().getResourceAsStream("cassandra_truststore.jks");
ks.load(in, SSL_CASSANDRA_PASSWORD.toCharArray());
TrustManagerFactory tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
tmf.init(ks);
SSLContext ctx = SSLContext.getInstance("TLS");
ctx.init(null, tmf.getTrustManagers(), null);
return ctx;
} catch (Exception e) {
logger.error("Error CassandraConnector getSSLContext", e);
} finally {
if (in != null) {
try {
in.close();
} catch (IOException e) {
logger.error("", e);
}
}
}
return null;
}
}
应用程序.conf
datastax-java-driver {
basic.request {
timeout = 5 seconds
consistency = LOCAL_ONE
}
advanced.connection {
max-requests-per-connection = 1024
pool {
local.size = 1
remote.size = 1
}
}
advanced.reconnect-on-init = true
advanced.reconnection-policy {
class = ExponentialReconnectionPolicy
base-delay = 1 second
max-delay = 60 seconds
}
advanced.retry-policy {
class = DefaultRetryPolicy
}
advanced.protocol {
version = V4
}
advanced.heartbeat {
interval = 30 seconds
timeout = 1 second
}
advanced.session-leak.threshold = 8
advanced.metadata.token-map.enabled = false
}