Thank you all for advices.
I think, I have to give more details about my situation.
InfluxDB 1.0; Telegraf 1.0
I have Telegraf collecting metrics from a servers and pulling it into
InfluxDB. I use this InfluxDB as datasource for Grafana.
Mem is a standard measurement. It has "hosts" in tags.
What I want: I want to count hosts. So, if it was ordinary SQL, I can do
something like SELECT COUNT("hosts") FROM mem.
SHOW TAG VALUES FROM mem WITH KEY = "host" do the trick, but I need to get
it in Grafana. And there is no SHOW, only SELECT.
On Wednesday, September 28, 2016 at 6:15:37 PM UTC+3, Sean Beckett wrote:
>
> Do you have a field key named "value"? I was giving examples, but without
> access to your schema I can't give actual queries. However, the SHOW TAG
> VALUES FROM mem_usage_percent WITH KEY = "host" query gives you what you
> want. Did you try that?
>
> On Wed, Sep 28, 2016 at 5:35 AM, Paul Letskii <[email protected]
> <javascript:>> wrote:
>
>> I'm still getting empty result:
>>
>> SELECT "host", "value" FROM mem WHERE time < now() - 2m
>>
>> Success! (no results to display)
>>
>> My goal is to count number of hosts and get this number into Grafana.
>>
>>
>>
>> On Tuesday, September 27, 2016 at 6:41:30 PM UTC+3, Sean Beckett wrote:
>>>
>>> That is because "host" is a tag
>>> <https://docs.influxdata.com/influxdb/v1.0/concepts/glossary/#tag>, not
>>> a field
>>> <https://docs.influxdata.com/influxdb/v1.0/concepts/glossary/#field>.
>>> SELECT statements must include at least one field.
>>>
>>> If you want only the values of "host", that's a SHOW
>>> <https://docs.influxdata.com/influxdb/v1.0/query_language/schema_exploration/#explore-tag-values-with-show-tag-values>
>>>
>>> query, not a SELECT
>>> <https://docs.influxdata.com/influxdb/v1.0/query_language/data_exploration/#the-select-statement-and-the-where-clause>
>>>
>>> query:
>>>
>>> SHOW TAG VALUES FROM mem_usage_percent WITH KEY = "host"
>>>
>>> Note that the SHOW query does not accept a "WHERE time" clause. To get
>>> hosts during a particular time, use a SELECT query with a field as well:
>>>
>>> SELECT "host", "value" FROM mem_usage_percent WHERE time > ...
>>>
>>>
>>>
>>> On Tue, Sep 27, 2016 at 12:04 AM, Paul Letskii <[email protected]> wrote:
>>>
>>>> Ok. But how have I change this query: "SELECT "host" FROM
>>>> "mem_usage_percent"" to get just hosts field?
>>>> According to documentation it is correct query (
>>>> https://docs.influxdata.com/influxdb/v1.0/query_language/data_exploration/#the-select-statement-and-the-where-clause
>>>> )
>>>>
>>>>
>>>> On Monday, September 26, 2016 at 6:00:06 PM UTC+3, Sean Beckett wrote:
>>>>>
>>>>> Every SELECT statement must have at least one field. You selecting
>>>>> only a tag. Use either "SHOW TAG VALUES" or include a field in the query.
>>>>>
>>>>> On Mon, Sep 26, 2016 at 6:55 AM, Paul Letskii <[email protected]>
>>>>> wrote:
>>>>>
>>>>>> Hi all!
>>>>>>
>>>>>> InfluxDB version 1.0\
>>>>>>
>>>>>> I'm trying to get list of hosts from measurement "mem_usage_percent".
>>>>>>
>>>>>> This query works:
>>>>>> SELECT * FROM "mem_usage_percent"
>>>>>>
>>>>>> This one doesn't:
>>>>>> SELECT "host" FROM "mem_usage_percent"
>>>>>> Accordingly to documentation it has to.
>>>>>>
>>>>>> My final goal is to count number of unique hosts. Like: SELECT
>>>>>> count("host") FROM "mem_usage_percent"
>>>>>>
>>>>>> What is correct syntax to get information from certain field?
>>>>>>
>>>>>> Thank you in advance!
>>>>>>
>>>>>> Best regards,
>>>>>> Paul Letskii
>>>>>>
>>>>>> --
>>>>>> Remember to include the InfluxDB version number with all issue reports
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>>>>>>
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>>>>>> .
>>>>>> For more options, visit https://groups.google.com/d/optout.
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Sean Beckett
>>>>> Director of Support and Professional Services
>>>>> InfluxDB
>>>>>
>>>> --
>>>> Remember to include the InfluxDB version number with all issue reports
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>>>> .
>>>>
>>>> For more options, visit https://groups.google.com/d/optout.
>>>>
>>>
>>>
>>>
>>> --
>>> Sean Beckett
>>> Director of Support and Professional Services
>>> InfluxDB
>>>
>> --
>> Remember to include the InfluxDB version number with all issue reports
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>> For more options, visit https://groups.google.com/d/optout.
>>
>
>
>
> --
> Sean Beckett
> Director of Support and Professional Services
> InfluxDB
>
--
Remember to include the InfluxDB version number with all issue reports
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