Closes #694 - Added option to expose counters as differences to influxDB exporter

[JonasKunz]

Closes #694

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This change is 

[mariusoe]

Reviewed 10 of 19 files at r1.
Reviewable status: 10 of 19 files reviewed, 10 unresolved discussions (waiting on @JonasKunz and @mariusoe)

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components/inspectit-ocelot-eum-server/src/main/resources/application.yml, line 121 at r1 (raw file):

        # This difference will only be written if the counter has changed (=the difference is non-zero).
        # This can greatly reduce the total data written to influx and makes writing queries easier.
        counters-as-differences: true

I think we have to discuss this.
I'm not sure if we should set this to true. This way, we break existing things because the exporting values are suddenly different after upgrading.
On the other hand, users may not change this behaviour at all.. Mabye we should keep this false by default for some versions..?

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inspectit-ocelot-config/src/main/resources/rocks/inspectit/ocelot/config/default/exporters.yml, line 47 at r1 (raw file):

        # This difference will only be written if the counter has changed (=the difference is non-zero).
        # This can greatly reduce the total data written to influx and makes writing queries easier.
        counters-as-differences: true

See comment in the EUM configuration regarding this field.

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inspectit-ocelot-documentation/docs/breaking-changes/1.3.md, line 22 at r1 (raw file):

InfluxDB exporter

..InfluxDB metrics exporter..

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inspectit-ocelot-documentation/docs/breaking-changes/1.3.md, line 22 at r1 (raw file):

and sum metrics, which is now the default behaviour.

let's discuss this

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inspectit-ocelot-documentation/docs/breaking-changes/1.3.md, line 23 at r1 (raw file):

influxDB

Let's write it as InfluxDB

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inspectit-ocelot-documentation/docs/breaking-changes/1.3.md, line 23 at r1 (raw file):

your queries will need to be reworked.

...your existing queries have to be reworked.

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inspectit-ocelot-documentation/docs/breaking-changes/1.3.md, line 24 at r1 (raw file):

 old 

previous

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inspectit-ocelot-documentation/docs/metrics/metric-exporters.md, line 59 at r1 (raw file):

When querying the data, usually the absolute value of such counters is irrelevant.
Instead all that matters is how much the counter has increased within a certain time interval.

Usually, the absolute value of such counters is irrelevant when querying the data, instead you want to have the increase of it over a certain period of time..

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inspectit-ocelot-documentation/docs/metrics/metric-exporters.md, line 61 at r1 (raw file):

Instead of writing the absolute value of each counter to InfluxDB, only the increase since the last export is exported.

Instead of writing the absolute value of each counter into the InfluxDB, only the increase since the last export will be written.

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inspectit-ocelot-documentation/docs/metrics/metric-exporters.md, line 63 at r1 (raw file):

to influx in case

...into the InfluxDB, especially if the metrics are quite constant and won't change much.

[mariusoe]

Reviewed 9 of 19 files at r1, 3 of 3 files at r2.
Reviewable status: complete! all files reviewed, all discussions resolved