Cassandra Java驱动程序协议版本和连接限制不匹配

本文介绍了Cassandra Java驱动程序协议版本和连接限制不匹配的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我正在使用Java驱动程序版本：2.1.4 Cassandra版本：dsc-cassandra-2.1.10 cql的输出给出以下内容

I am using java driver version: 2.1.4 Cassandra version: dsc-cassandra-2.1.10 Output from cql gives the following

cqlsh 5.0.1 | Cassandra 2.1.10 | CQL spec 3.2.1 | Native protocol v3

我是协议V3。但是，当我尝试将其设置为每个连接超过128个请求时，它将引发异常。这似乎是V2中的限制。解释如下：

I am protocol V3. But it throws an exception when I try to set it to more than 128 requests per connection. This seems to be a restriction in V2. Explained below:

以下代码块：

PoolingOptions poolingOptions = new PoolingOptions(); poolingOptions.setCoreConnectionsPerHost(HostDistance.LOCAL, 8); Cluster cluster = Cluster.builder() .addContactPoints(x.x.x.x) .withPoolingOptions(poolingOptions) .withProtocolVersion(ProtocolVersion.V3) .build(); System.out.println("Protocol version = "+myCurrentVersion); System.out.println("LOCAL CORE = "+poolingOptions.getCoreConnectionsPerHost(HostDistance.LOCAL)); System.out.println("LOCAL MAX = "+poolingOptions.getMaxConnectionsPerHost(HostDistance.LOCAL)); System.out.println("Max sim requests = "+poolingOptions.getMaxSimultaneousRequestsPerConnectionThreshold(HostDistance.LOCAL)); System.out.println("Max sim requests per host = "+poolingOptions.getMaxSimultaneousRequestsPerHostThreshold(HostDistance.LOCAL)); poolingOptions .setMaxSimultaneousRequestsPerHostThreshold(HostDistance.LOCAL, 3000); poolingOptions .setMaxSimultaneousRequestsPerConnectionThreshold(HostDistance.LOCAL, 128); System.out.println("LOCAL CORE = "+poolingOptions.getCoreConnectionsPerHost(HostDistance.LOCAL)); System.out.println("LOCAL MAX = "+poolingOptions.getMaxConnectionsPerHost(HostDistance.LOCAL)); System.out.println("Max sim requests = "+poolingOptions.getMaxSimultaneousRequestsPerConnectionThreshold(HostDistance.LOCAL)); System.out.println("Max sim requests per host = "+poolingOptions.getMaxSimultaneousRequestsPerHostThreshold(HostDistance.LOCAL));

输出为：

Protocol version = V3 LOCAL CORE = 1 LOCAL MAX = 8 Max sim requests = 100 Max sim requests per host = 1024 Exception in thread "main" java.lang.IllegalArgumentException: Max simultaneous requests per connection for LOCAL hosts must be in the range (0, 128) at com.datastax.driver.core.PoolingOptions.checkRequestsPerConnectionRange(PoolingOptions.java:370) at com.datastax.driver.core.PoolingOptions.setMaxSimultaneousRequestsPerConnectionThreshold(PoolingOptions.java:175) at ca.txio.pricehistoryservice.main.ConnectionOptionTest.main(ConnectionOptionTest.java:38)

根据Cassandra文档 > docs.datastax/en/developer/java-driver/2.1/manual/native_protocol/ 和 > docs.datastax/en/developer/java-driver/2.1 / manual / pooling /

According to the Cassandra documentation docs.datastax/en/developer/java-driver/2.1/manual/native_protocol/ and docs.datastax/en/developer/java-driver/2.1/manual/pooling/

我是协议V3。但是为什么我每个连接限制为128个请求。这似乎是V2中的限制。有人可以解释一下如何找到我的实际版本，如果确实是V3，为什么我不能同时建立128个以上的并行连接？

I am protocol V3. But why am I restricted to 128 requests per connection. This seems to be a restriction in V2. Could someone please explain how to find what version I actually am, and if indeed V3, why can't I have more than 128 simultaneous connections?

推荐答案

对于ProtocolVersion＃V3或更高版本，每个连接最多有32768个请求，并且该池默认为固定大小1。通常，通过允许每个连接同时发出更多请求来提高最大容量（ setMaxRequestsPerConnection （HostDistance，int））

With ProtocolVersion#V3 or above, there are up to 32768 requests per connection, and the pool defaults to a fixed size of 1. You will typically raise the maximum capacity by allowing more simultaneous requests per connection (setMaxRequestsPerConnection(HostDistance, int))

参考： docs.datastax/en/drivers/java /2.1/com/datastax/driver/core/PoolingOptions.html#setMaxRequestsPerConnection-com.datastax.driver.core.HostDistance-int-