Use errGroup in handleValuePostings

[jarifibrahim]

Description.

This PR improves the handling of goroutines in handleValuePostings function. The function starts a bunch of goroutines but doesn't wait for them to complete. This PR fixes that isssue.

GitHub Issue or Jira number.

Partially fixes #3873
See also #3873 (comment)

Affected releases.

v20.03

Changelog tags.

N/A

Please indicate if this is a breaking change.

No

Please indicate if this is an enterprise feature.

No

Please indicate if documentation needs to be updated.

No

Please indicate if end to end testing is needed.

No

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This change is 

[gja]

Reviewed 2 of 2 files at r1.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @manishrjain)

[gja]

I assume this is just a refactor, there is no additional functionality? If so,

Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @manishrjain)

[martinmr]

Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @jarifibrahim and @manishrjain)

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worker/task.go, line 495 at r1 (raw file):

			s := start
			e := end

I don't think you need to do this. I am assuming this is to copy the values and prevent them from changing. But these values will be copied to the arguments because they are just numbers if you just call return calculate(start, end) instead

[jarifibrahim]

Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @manishrjain and @martinmr)

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worker/task.go, line 495 at r1 (raw file):

Previously, martinmr (Martin Martinez Rivera) wrote…

			s := start
			e := end

I don't think you need to do this. I am assuming this is to copy the values and prevent them from changing. But these values will be copied to the arguments because they are just numbers if you just call return calculate(start, end) instead

Oh, right. They're being initialized inside the for loop. Nice catch @martinmr, Thank you!