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CBG-4734: fix for race when removing a value that is being loaded into rev cache #7640

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Merged
merged 3 commits into from
Aug 1, 2025
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CBG-4734: fix for race when removing a value that is being loaded into rev cache #7640

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13c4639
CBG-4734: fix for race when removing a value that is being loaded int…
gregns1 Jul 22, 2025
98a9d0a
update retry description
gregns1 Jul 22, 2025
ecb6c10
add new method to remove from rev lookup but not cv lookup and soem c…
gregns1 Jul 30, 2025
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20 changes: 20 additions & 0 deletions db/revision_cache_lru.go
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Original file line number Diff line number Diff line change
Expand Up @@ -518,6 +518,16 @@ func (rc *LRURevisionCache) removeFromCacheByCV(ctx context.Context, docID strin
}
// grab the revid key from the value to enable us to remove the reference from the rev lookup map too
elem := element.Value.(*revCacheValue)

// we can only remove this value if the value has finished loading from the bucket
_, _ = base.RetryLoop(ctx, "remove from revision cache by rev", func() (shouldRetry bool, err error, _ any) {
if !elem.canEvict.Load() {
// value is still in process of being loaded from bucket, we need to wait for this to finish
return true, nil, nil
}
return false, nil, nil
}, base.CreateMaxDoublingSleeperFunc(30, 10, 500))

legacyKey := IDAndRev{DocID: docID, RevID: elem.revID, CollectionID: collectionID}
rc.lruList.Remove(element)
delete(rc.hlvCache, key)
Expand All @@ -538,6 +548,16 @@ func (rc *LRURevisionCache) removeFromCacheByRev(ctx context.Context, docID, rev
}
// grab the cv key from the value to enable us to remove the reference from the rev lookup map too
elem := element.Value.(*revCacheValue)

// we can only remove this value if the value has finished loading from the bucket
_, _ = base.RetryLoop(ctx, "remove from revision cache by rev", func() (shouldRetry bool, err error, _ any) {
if !elem.canEvict.Load() {
// value is still in process of being loaded from bucket, we need to wait for this to finish
return true, nil, nil
}
return false, nil, nil
}, base.CreateMaxDoublingSleeperFunc(30, 10, 500))

hlvKey := IDandCV{DocID: docID, Source: elem.cv.SourceID, Version: elem.cv.Value, CollectionID: collectionID}
rc.lruList.Remove(element)
// decrement the overall memory bytes count
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