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apache / iotdb

Apache IoTDB
https://iotdb.apache.org/
Apache License 2.0
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Question: Storing last value only and storing static data. #2528

Open ope-nz opened 3 years ago

ope-nz commented 3 years ago

I am collecting IT infrastructure metrics - cpu, ram, network I/O etc. which fits nicely in iotDB since I need to track this over time.

I am also collecting infrastructure detail such as up time, host operating system etc.

As the uptime (as a long integer) is always increasing I dont need to keep the data in a timeseries and I am only interested in the last value as such I am storing this in a relational database along with other static data such as host OS name which should never change. The data is collected ever 5 minutes but is unlikely to change so I just do an "update" statement in the RDBMS.

I would like to store this in iotDB if possible to avoid having to support 2 databases.

Is there a way to;

  1. Store static information which does not change?
  2. Store a long integer but only keep the last value?

Should I use TTL to limit the amount of data? I only see reference to TTL at the storage group level. Im guessing TTL isnt the answer since all data may disappear if the host stops sending data.

Should I delete and insert every time? Will this affect performance?

wangchao316 commented 3 years ago

hi , if delete and insert every time, this will affect performance, due to delete data, will generate alone tsfile, merge-operate only dispelled this file, which affect query performance.

ope-nz commented 3 years ago

Thanks @wangchao316 should I avoid having this data in iotDB or should I use TTL? I can probably keep this data in a separate storage group and use TTL of 1 week.

Does TTL have the same issue as delete operation?