loadbalancing exporter seems to eat data if fed identical attributes for a datapoint + timestamp

[skandragon]

Component(s)

exporter/loadbalancing

What happened?

Description

The load balancing exporter uses a Merge helper that seems like it will destroy data when duplicate data flows through it.

Steps to Reproduce

1. Take any metric flow, and drop a tag using any of the filtering processors.
2. Note that now the metrics for a given timestamp have more than one entry for the same set of attributes and timestamp.
3. Note that the routing seems to drop one of thees when merging prior to routing.

Expected Result

It should not drop data.

Actual Result

It drops data.

Collector version

v0.114.0

Environment information

go latest, any linux

OpenTelemetry Collector configuration

No response

Log output

No response

Additional context

No response

[github-actions]

Pinging code owners:

• exporter/loadbalancing: @jpkrohling

See Adding Labels via Comments if you do not have permissions to add labels yourself.

[JaredTan95]

@skandragon hi, It is convenient to provide a reproducible step or configuration?

[skandragon]

Easy? no, as it's pretty data dependent. However, the setup as described in the top comment will reproduce this: just dropping any tag with multiple datapoints that now have the same attributes and timestamp, but different values. One will be dropped at random.

[atoulme]

If two data points have the same attributes and timestamps, is it valid that they exist twice with 2 values?

[atoulme]

This should be reproducible with a failing unit test, if this is indeed something worth fixing. @skandragon would you like to offer such a test case?

[skandragon]

Sure. Working on it.

[skandragon]

And... mis-clicked. Will re-open with a unit test included unless someone with permissions can re-open this one.

[github-actions]

This issue has been inactive for 60 days. It will be closed in 60 days if there is no activity. To ping code owners by adding a component label, see Adding Labels via Comments, or if you are unsure of which component this issue relates to, please ping @open-telemetry/collector-contrib-triagers. If this issue is still relevant, please ping the code owners or leave a comment explaining why it is still relevant. Otherwise, please close it.

Pinging code owners:

• exporter/loadbalancingexporter: @rlankfo

See Adding Labels via Comments if you do not have permissions to add labels yourself.