Restoring backup to existing database fail to search

Hey everyone!

I created a portable backup of collectd database and then deleted some data from there by using DELETE command to free some space. After some time I decided to restore the data I deleted so I restore data to collectd_bak database and from there with the following select:

SELECT * INTO collectd.autogen.cpu FROM collectd_bak.autogen.cpu WHERE time >= 26w

measurement by measurement I moved data from collectd_bak to collectd. Have to say that I’ve got two retention policies in both databases (autogen and aggregated). So for autogen I used WHERE clause with time and for aggregated retention policy I didn’t.

Everythig seemed going well but then, when I wanted to search some stuff with Grafana it shows me only data for Last 2days. When I try to search 7d and more it says no data. Also restored database collectd_bak has size around 5G and collectd after I moved databa has 13G. I think that Influx somehow changed the data with the SELECT or so…

Grafana query:

SELECT mean("value") FROM "snmp_value" WHERE ("type_instance" = 'load_5min' AND "host" = 'host1') AND $timeFilter GROUP BY time($__interval)

If anyone ran into the same problem please help ))

Thank you in advance for any suggestions!!!

So I figured out where the problem is.

I think that tags of measurements were overwritten while restoring the data to existing database and retention policies.

> select * from cpu_value where time > '2020-08-03T23:58:58Z' AND time < '2020-08-03T23:59:59Z'
name: cpu_value
time                host host_1    instance instance_1 type type_1 type_instance type_instance_1 value
----                ---- ------    -------- ---------- ---- ------ ------------- --------------- -----
1596499140248239662      localhost          0               cpu                  user            11133579
1596499140248245535      localhost          1               cpu                  user            11110183

The right format of the measurement is

> select * from cpu_value where time > '2020-08-06T23:58:58Z' AND time < '2020-08-07T23:59:59Z' limit 1
name: cpu_value
time                host      instance type type_instance value
----                ----      -------- ---- ------------- -----
1596758339604275646 localhost 0        cpu  user          1798908

The tags with names type_1, host_1 and type_instance_1 cause problem to Grafana to query the data.

Is there any option to change the names of the tags?

Thanks!

Hello @vladpov,
You can use flux to rename tag values with a map() function:https://v2.docs.influxdata.com/v2.0/reference/flux/stdlib/built-in/transformations/map/
Or you might have luck with the Telegraf rename processor plugin: https://github.com/influxdata/telegraf/tree/master/plugins/processors/rename

@Anaisdg thank you for reply! Unfortunately I’m not sure if I really got how to use the map() function to rename the tags from the documentation you offer ((

My idea is to do something similar to the following:

SELECT host_1 as host, instance_1 AS instance, type_1 AS type, type_instance_1 AS type_instance INTO changed.value.autogen:MEASUREMENT FROM cpu_value WHERE time > 'sometime' AND time < 'sometime'

And after that I’d move data with the correct tag names back to the database…

Could you please use an example of what you suggest?

Thank you very much!!

Hello @vladpov,
To rename tags, more likely I’d use rename():
Something like

|> from(bucket:"mybucket")
|> range(start:-5m)
|> rename(columns: {host_1: "host", instance_1: "instance", etc...})