inserting data into timestream table

Hi.

The data comes from an mqtt topic, and can be seen in the cloudwatch log, so I know my select statement is sound. I think i have given the IAM role the correct permissions.

Are you looking in the AWSIotLogsV2 log group? And at the RuleMatch and RuleExecution event types?

https://docs.aws.amazon.com/iot/latest/developerguide/cwl-format.html#rule-engine-logs

If your rule is suffering an error during the rule action, you should see it in the RuleExecution event type.

One further question, why, after i have deactiveted a rule, does it still appear in the cloudwatch logs?

This question makes me think you're not looking at RuleExecution.

describes how to enter the 'timestamp value' but does not say what is needed in the 'timestamp unit' field

time_to_epoch() returns the epoch time in milliseconds.

https://docs.aws.amazon.com/iot/latest/developerguide/iot-sql-functions.html#iot-sql-function-time-to-epoch