Only backup the predicates belonging to a group.

[martinmr]

This PR changes the backup request to include the list of predicates in
the group. This list is used by the ChooseKey function to skip any keys
not belonging to the specified predicates.

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This change is 

[manishrjain]

One comment. Do address before merging.

Reviewed 4 of 4 files at r1.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @martinmr)

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ee/backup/backup.go, line 95 at r1 (raw file):

	stream.ChooseKey = func(item *badger.Item) bool {
		parsedKey := x.Parse(item.Key())
		for _, pred := range pr.Request.Predicates {

Better to make a map out of it, considering how many keys would need to check for this.

[martinmr]

Reviewable status: 1 of 4 files reviewed, 1 unresolved discussion (waiting on @manishrjain)

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ee/backup/backup.go, line 95 at r1 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Better to make a map out of it, considering how many keys would need to check for this.

Done.