CODEWITHSUNDEEP
grammarapache-iotdb
user21515202
user21515202

Reputation: 9

How to check the grammar of time series name to avoid reporting "empty set" when querying in Apache IoTDB?

I used the "select * from root.jj.1#_10#.*" statement to query data in Apache IoTDB Version 1.0.0, but it reported an empty set when this time series has data in it. I checked the official website of IoTDB, and it seems like this is a problem related to grammar checks. However when I inserted data before, no error is reported, and also a new time series is automatically created when there is no available time series. Does anyone know how to solve this problem?

Can anyone deal with this problem？ Help, please

Upvotes: 0

Views: 22

Answers (1)

user20871424
user20871424

Reputation: 1

Did you create time series using "session" interface? In Apache IoTDB Version 1.0.0, the data written by the "session" interface did not do grammar check, so when you wrote them you may not add backticks, then this error will report when data entered IoTDB.

You can upgrade to Version 1.1.0. In this version, if you do not add backticks, an error will be directly reported, because "#" is a special character that needs to be enclosed in backticks, so when writing, you have to add backticks.

About why you did not see an error when inseting data: the written session has no verification, so it is written successfully to the database. However, when you try to query, this process has verification, so an error will be reported if the grammar is wrong. The time series does not exist after translating, so no error is found in the query.

Upvotes: 0

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