Export and import with specified precision

[samaust]

Goal

Migrate data from a previous version of InfluxDB to a more recent version while specifying precision

What I did

I'm migrating data from InfluxDB 1.8 to InfluxDB 2.4.
I know that all data in a specific database in InfluxDB 1.8 was written with second precision.
I exported the data from InfluxDB 1.8 using influx_inspect export.
The time is exported with nanosecond precision,
I compressed the data using --compress to reduce filesize.

I imported the data successfully in InfluxDB 2.4 with nanosecond precision using influx write.

I get an error if I try to import the data with second precision. If I add --precision s, I get the output :
unable to parse '<my query> 1661386584000000000': time outside range -9223372036854775806 - 9223372036854775806

Suggestions

1. Export : Add a flag to set export precision
2. Import : Modify influx write to truncate the time if --precision other than ns is set.

Known issues

• If data is exported with a lower precision than what the data was initially written with, there might be duplicate lines with the same time in the export file.
• If data is imported with a lower precision than is contained in the export file, there might be duplicate lines with the same time. Data might be overwritten in InfluxDB.

Both of these are not a problem because setting the flag is a decision by the developer.

Related documentation

https://docs.influxdata.com/influxdb/v1.8/tools/influx_inspect/#export
https://docs.influxdata.com/influxdb/v2.4/reference/cli/influxd/inspect/export-lp/