我们可以像这样创建一个集群实例。
cluster = Cluster
.builder()
.addContactPoint("192.168.0.30")
.withRetryPolicy(DefaultRetryPolicy.INSTANCE)
.build();
我们是否会在查询时提供重试请求的时间信息。
感谢任何建议。
由于
答案 0 :(得分:18)
为了指定这些值,您必须创建自己的RetryPolicy
interface实现。
以下只是一个示例 - 根据您的规则制作您自己的实现:
public class CustomRetryPolicy implements RetryPolicy {
private final int readAttempts;
private final int writeAttempts;
private final int unavailableAttempts;
public CustomRetryPolicy(int readAttempts, int writeAttempts, int unavailableAttempts) {
this.readAttempts = readAttempts;
this.writeAttempts = writeAttempts;
this.unavailableAttempts = unavailableAttempts;
}
@Override
public RetryDecision onReadTimeout(Statement stmnt, ConsistencyLevel cl, int requiredResponses, int receivedResponses, boolean dataReceived, int rTime) {
if (dataReceived) {
return RetryDecision.ignore();
} else if (rTime < readAttempts) {
return RetryDecision.retry(cl);
} else {
return RetryDecision.rethrow();
}
}
@Override
public RetryDecision onWriteTimeout(Statement stmnt, ConsistencyLevel cl, WriteType wt, int requiredResponses, int receivedResponses, int wTime) {
if (wTime < writeAttempts) {
return RetryDecision.retry(cl);
}
return RetryDecision.rethrow();
}
@Override
public RetryDecision onUnavailable(Statement stmnt, ConsistencyLevel cl, int requiredResponses, int receivedResponses, int uTime) {
if (uTime < unavailableAttempts) {
return RetryDecision.retry(ConsistencyLevel.ONE);
}
return RetryDecision.rethrow();
}
}
这很容易......然后你将它传递到Cluster
...
RetryPolicy rc = new CustomRetryPolicy(3, 3, 2);
Cluster cluster = Cluster.builder().addContactPoint("192.168.0.30").withRetryPolicy(rc).build();
HTH, 卡罗
答案 1 :(得分:0)
对于使用.NET的CassandraCSharpDriver NuGet软件包的C#开发人员,我无耻地复制了Carlo Bertuccini的出色答案,并将其转换为C#语法:
CustomRetryPolicy customRetryPolicy = new CustomRetryPolicy(10, 10, 10);
cluster = Cluster.Builder().WithRetryPolicy(customRetryPolicy).WithCredentials(USER, PASS).AddContactPoint(NODE).WithCompression(CompressionType.Snappy).Build();
班级:
public class CustomRetryPolicy : IRetryPolicy
{
private int readAttempts;
private int writeAttempts;
private int unavailableAttempts;
public CustomRetryPolicy(int readAttempts, int writeAttempts, int unavailableAttempts)
{
this.readAttempts = readAttempts;
this.writeAttempts = writeAttempts;
this.unavailableAttempts = unavailableAttempts;
}
public RetryDecision OnReadTimeout(IStatement query, ConsistencyLevel cl, int requiredResponses, int receivedResponses, bool dataRetrieved, int nbRetry)
{
if (dataRetrieved)
{
return RetryDecision.Ignore();
}
else if (nbRetry < readAttempts)
{
return RetryDecision.Retry(cl);
}
else
{
return RetryDecision.Rethrow();
}
}
public RetryDecision OnUnavailable(IStatement query, ConsistencyLevel cl, int requiredReplica, int aliveReplica, int nbRetry)
{
if (nbRetry < unavailableAttempts)
{
return RetryDecision.Retry(ConsistencyLevel.One);
}
return RetryDecision.Rethrow();
}
public RetryDecision OnWriteTimeout(IStatement query, ConsistencyLevel cl, string writeType, int requiredAcks, int receivedAcks, int nbRetry)
{
if (nbRetry < writeAttempts)
{
return RetryDecision.Retry(cl);
}
return RetryDecision.Rethrow();
}
}