[IOTDB-1367] [Distributed] Runtime exception is not properly handled during forwarding

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: Core/Cluster
• Labels: client-me distributed query
• Assignee: Unassigned
• Reporter: Tian Jiang
• Created: 07/May/21 12:27
• Updated: 09/Nov/21 02:47

Description

When I executed `select avg(s_0) from root.group_0.d_20` (notice that s_0 is boolean and does not support avg), I got `Msg: 313: Request "Query aggregate: root.group_0.d_20.s_0 in [Node(internalIp:192.168.130.4, metaPort:9003, nodeIdentifier:1436654207, dataPort:40003, clientPort:6667, clientIp:0.0.0.0)]" timeout`. While the log on node 192.168.130.4 says:

The cause is that RunTimeExceptions are not caught explicitly in DataClusterServer and MetaClusterServer, so they are converted to TExceptions by Thrift and are recognized as network problems by the coordinator.

The solution is either to catch runtime exceptions explicitly and create status codes for them or make the coordinator capable of resolving more TExceptions. Both ways have their difficulties, for the first one, it is nearly impossible to know how many runtime exceptions can occur; for the second one, when an exception is converted to a TException, only its message remains, so it is not easy to determine what exactly the problem is.

ps: this only occurs when the coordinator does not have the corresponding data, so try querying another node if you can not repeat it.