Cassandra C#驱动程序手动分页不工作

Question

我正在尝试使用C#在Cassandra中使用手动分页。

以下是版本详细信息：

它是驱动程序版本3.11.0

我的服务器版本是[cqlsh 5.0.1|Cassandra 3.11.4|CQL规范3.4.4|Native protocol v4]

下面是我正在尝试的代码

var cluster = Cluster.Builder()
.AddContactPoints("x.x.x.x", "x.x.x.x", "x.x.x.x")
.WithCompression(CompressionType.Snappy)
.Build();
var session = cluster.Connect("shekhar");
var statement = new SimpleStatement("select * from table ALLOW FILTERING");
statement.SetAutoPage(false);
statement.SetPageSize(1000);
var rs = await session.ExecuteAsync(statement);
int rowNo = 0;
foreach (var row in rs)
Console.WriteLine("{0}: Cooment has Id {1}, has tweet {2}", rowNo++, row.GetValue<BigInteger>("id"), row.GetValue<string>("xxx"));
//rs.FetchMoreResults();
//Console.WriteLine(rs.IsExhausted());
//Console.WriteLine(rs.IsFullyFetched);
//Console.WriteLine(rs.PagingState);

通过设置语句.SetAutoPage(false(它只获取一页
最后一条语句Console.WriteLine(rs.IsFullyFetched);和Console.WriteLine(rs.IsFullyFetched);的值是true，因此也使用它们不会有任何区别。

我也遵循了关于https://docs.datastax.com/en/developer/csharp-driver/3.13/features/paging/在下一个语句中使用PagingState的部分手动分页
使用此功能可以保持一次又一次地提取旧数据。

这是我对同一的实现

var statement = new SimpleStatement("select * from table ALLOW FILTERING");
statement.SetAutoPage(false);
statement.SetPageSize(1000);
int rowNum = 0;
await GetAllData_PagedData(session, statement, null, rowNum);
Console.ReadLine();
static async Task GetAllData_PagedData(ISession session, IStatement statement, byte[] pagingState, int rowNum)
{
var statement2 = statement
.SetPagingState(pagingState);
var rs2 = session.Execute(statement2);
var pagingState1 = rs2.PagingState;
foreach (var row in rs2)
{
Console.WriteLine("{0}: Cooment has Id {1}, has tweet {2}", rowNum++, row.GetValue<BigInteger>("id"), row.GetValue<string>("column2"));
}
if (!rs2.IsFullyFetched)
await GetAllData_PagedData(session, statement2, pagingState1, rowNum);
else
Console.WriteLine("All Data fetched...");
}

Answer 1

尝试用if (pagingState1 != null)替换if (!rs2.IsFullyFetched)。

在禁用AutoPage的情况下，IsFullyFetched方法总是返回true，因为它旨在与RowSet的自动分页功能一起使用。