使用函数concatDateTime https://www.dolphindb.cn/cn/help/200/FunctionsandCommands/FunctionReferences/c/concatDateTime.html?highlight=concatdatetime
回答于 2023-06-07 10:14
按年分区即可,每年大约140MB数据,参考如下代码: years = sort(distinct(yearBegin(2010.01.01..2022.01.01)))dfsPath = "dfs://test_1"db = database(dfsPath, RANGE, years)
回答于 2023-06-07 10:12
可以通过getpersistencemeta检查下流表最小的offset https://www.dolphindb.cn/cn/help/200/FunctionsandCommands/FunctionReferences/g/getPersistenceMeta.html?highlight=getpersistencemeta raftGroup: -1sizeOnDisk: 9,074,082memoryOffset: 8,931,944diskOffset: 3,214,397asynWrite: truesizeInMemory: 142,138c...
回答于 2023-06-06 17:45
dolphindb 写入文件的权限是对应进程用户的权限,组权限受umask限制。如果要组也默认有权限,需要设置umask 0002。 如果是systemd启动的可以在服务配置加一个配置选项 [Service]UMask=0002
回答于 2023-06-02 17:23
IO_ERROR 1一般是API主动关闭了连接,server升级到2.00.9版本以后python sdk也要升级到最新版本,否则无法订阅新版本流数据。
回答于 2023-05-29 10:36
使用元编程 h=columnNames(hot) makeCall(ols, sqlCol(yColName), makeUnifiedCall(matrix, sqlCol(h)), 1, 2)
回答于 2023-05-24 10:59
使用each + call 参考https://www.dolphindb.cn/cn/help/200/Functionalprogramming/TemplateFunctions/call.html?highlight=call
回答于 2023-05-24 10:33
使用fixedLengthArrayVector t = table(rand(10,5) as a1, rand(10,5) as a2, rand(10,5) as a3, rand(10,5) as a4, rand(10,5) as a5)select fixedLengthArrayVector(a1,a2,a3,a4,a5) as a from t
回答于 2023-05-24 10:32