feat(ha_tracker): Replicadesc implement mergeable interface #10020
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pkg/distributor/ha_tracker_test.go
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| rDesc2: nil, | ||
| expectedOurs: func() *ReplicaDesc { | ||
| ours2, _ := merge(secondReplica(), thirdReplica()) | ||
| ours2, _ = merge(ours2, firstReplica()) |
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| ours2, _ = merge(ours2, firstReplica()) | |
| ours2, _ = merge(firstReplica(), ours2) |
nit, but that's what the description says
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Correct, I updated it. Thank you 🙌
pkg/distributor/ha_tracker_test.go
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| name: "idempotency: no change after applying same Replica again", | ||
| rDesc1: expectedFirstAndFirstHigherReceivedAtMerge(), | ||
| rDesc2: firstReplica(), |
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i'd make this super explicit and call merge twice. Here the first merge is implicit: you've done it by hand in the test setup with expectedFirstAndFirstHigherReceivedAtMerge.
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Yes , you are right. I fixed it here 2ceeadc
| return out, nil | ||
| } | ||
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| // MergeContent noOp currently | ||
| // MergeContent describes content of this Mergeable. | ||
| // Given that ReplicaDesc can have only one instance at a time, it returns the ReplicaDesc it contains. | ||
| func (r *ReplicaDesc) MergeContent() []string { | ||
| result := []string(nil) | ||
| if len(r.Replica) != 0 { |
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WDYT about using r.IsEmpty() here?
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Cannot find this function as part of the ReplicaDesc, do you want me to implement it ?
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What this PR does
In this PR, we implement the
Mergeableinterface forReplicaDescand add tests to verify the implementation. Below, I will describe the high-level algorithm chosen for the Merge function.It’s important to note that the
Mergeableinterface was created with the assumption that the objects implementing it would maintain a "view" (list) of items over which they would iterate. At least based on my understanding after implementing,. In this case, there is only one instance ofReplicaDescfor each key.Merge
We can have 2 possible cases:
In the first case, the incoming Mergeable has the same Replica name as the one already in the KVStore. In this scenario, we keep the one with the most recent timestamp. If the timestamps are the same, we only update if the incoming one has been marked as deleted, in which case we need to make the KVStore aware of the deletion.
In the second case, the incoming Mergeable has a different Replica name. Here, we use the electedAt timestamp to decide which of the two ReplicaDesc objects should be retained.
Which issue(s) this PR fixes or relates to
Fixes #https://github.com/grafana/mimir-squad/issues/2653
Checklist
CHANGELOG.mdupdated - the order of entries should be[CHANGE],[FEATURE],[ENHANCEMENT],[BUGFIX].about-versioning.mdupdated with experimental features.