In this post we recap the week’s most interesting InfluxDB and TICK-stack related issues, workarounds, how-tos and Q&A from GitHub, IRC and the InfluxDB Google Group that you might have missed.

Performance implications of timestamp precision

Q: I’m writing second-resolution data to InfluxDB using the HTTP API. Does it matter if I specify nanosecond precision timestamps with no `precision` query string parameter or second precision timestamps with the `precision` parameter?

So, is there any benefit to using one of the two following requests?

curl -i -XPOST "http://localhost:8086/write?db=weather" --data-binary 'temperature,location=1 value=90 1472666050000000000'

curl -i -XPOST "http://localhost:8086/write?db=weather&precision=s" --data-binary 'temperature,location=1 value=90 1472666050'

A: Yes. To maximize performance we recommend using the coarsest possible timestamp precision when writing data to InfluxDB. Specifying `precision=s` is the way to go!

Performing the same function on multiple fields

Q: I want to calculate the average for every field in a single measurement. Currently, I’m using the query below which takes a long time to write out. Is there a better way to do this?

> SELECT mean("alarm") AS "ave_alarm",mean("guests") AS "ave_guests",mean("temperature") AS "ave_temperature" FROM "home"
name: home
time  ave_alarm  ave_guests  ave_temperature
0     0          1           70

A: Yes! Starting with version 1.0, aggregation functions support using an `*` to specify all fields in the measurement.

> SELECT mean(*) FROM "home"
name: home
time  mean_alarm  mean_guests  mean_temperature
0     0           1            70

Finding the most common field value

Q: Is there a way to find the most common field value in a field?

A: Starting with version 1.0, InfluxDB supports the `mode()` function which finds the most frequent value in a field. Check out the functions page for more information.

For more InfluxDB tips, see our Frequently Asked Questionspage and feel free to post your questions in the InfluxDB users group.

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