因此，我尝试使用具有以下查询级别设置的java datastax 3.1驱动程序获取cassandra表中的所有记录（~10k记录）：

// |query| reads all records in a table (select * from table)
// Setting read timeout as 10 minutes
query.setReadTimeoutMillis(600000);
// Set page size as 1000
query.setFetchSize(1000);

cassandra服务器设置为默认值（所有默认超时）。它是一个三节点集群。
驱动程序能够成功读取前1000条记录，但每次驱动程序试图获取下1000条记录时，我都会出现以下错误。

com.datastax.driver.core.exceptions.ReadTimeoutException: Cassandra timeout during read query at consistency LOCAL_ONE (1 responses were required but only 0 replica responded)
    at com.datastax.driver.core.exceptions.ReadTimeoutException.copy(ReadTimeoutException.java:88)
    at com.datastax.driver.core.exceptions.ReadTimeoutException.copy(ReadTimeoutException.java:25)
    at com.datastax.driver.core.DriverThrowables.propagateCause(DriverThrowables.java:37)
    at com.datastax.driver.core.ArrayBackedResultSet$MultiPage.prepareNextRow(ArrayBackedResultSet.java:312)
    at com.datastax.driver.core.ArrayBackedResultSet$MultiPage.isExhausted(ArrayBackedResultSet.java:269)
    at com.datastax.driver.core.ArrayBackedResultSet$1.hasNext(ArrayBackedResultSet.java:143)
    ... <some more stacktrace of custom codebase trying to read all rows in a table>
Caused by: com.datastax.driver.core.exceptions.ReadTimeoutException: Cassandra timeout during read query at consistency LOCAL_ONE (1 responses were required but only 0 replica responded)
    at com.datastax.driver.core.exceptions.ReadTimeoutException.copy(ReadTimeoutException.java:115)
    at com.datastax.driver.core.Responses$Error.asException(Responses.java:124)
    at com.datastax.driver.core.RequestHandler$SpeculativeExecution.onSet(RequestHandler.java:500)
    at com.datastax.driver.core.Connection$Dispatcher.channelRead0(Connection.java:1012)
    at com.datastax.driver.core.Connection$Dispatcher.channelRead0(Connection.java:935)
    at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:342)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:328)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:321)
    at io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:266)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:342)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:328)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:321)
    at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:342)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:328)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:321)
    at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:293)
    at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:267)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:342)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:328)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:321)
    at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1280)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:342)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:328)
    at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:890)
    at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:131)
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:564)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:505)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:419)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:391)
    at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:112)
    at java.lang.Thread.run(Thread.java:748)
Caused by: com.datastax.driver.core.exceptions.ReadTimeoutException: Cassandra timeout during read query at consistency LOCAL_ONE (1 responses were required but only 0 replica responded)
    at com.datastax.driver.core.Responses$Error$1.decode(Responses.java:62)
    at com.datastax.driver.core.Responses$Error$1.decode(Responses.java:37)
    at com.datastax.driver.core.Message$ProtocolDecoder.decode(Message.java:277)
    at com.datastax.driver.core.Message$ProtocolDecoder.decode(Message.java:257)
    at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:88)
    ... 19 common frames omitted

因此，读取表中所有记录的服务进入崩溃循环，每次都有相同的异常。
令我惊讶的是，这个异常总是在读取第1000条记录后的10秒内发生。默认情况下，10sec是cassandra服务器端超时，对于我的查询，应该将其覆盖为600sec（显然没有发生这种情况）。有人能解释一下为什么会这样吗？
p、 在苦苦寻找根源之后，我重新启动了Cassandra。瞧！，之后一切都很顺利，所有的记录都是一页一页地读，处理起来没有任何问题。