vrg: synchronize map writes #2065
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| ramen "github.com/ramendr/ramen/api/v1alpha1" | ||
| "github.com/ramendr/ramen/internal/controller/util" | ||
| corev1 "k8s.io/api/core/v1" | ||
| ctrl "sigs.k8s.io/controller-runtime" | ||
| ) | ||
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| var vrgLastUploadVersion = map[string]string{} | ||
| var vrgLastUploadVersion sync.Map |
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sync.Map is recommended only for special cases:
The Map type is specialized. Most code should use a plain Go map instead, with separate locking or coordination, for better type safety and to make it easier to maintain other invariants along with the map content.
The Map type is optimized for two common use cases: (1) when the entry for a given key is only ever written once but read many times, as in caches that only grow, or (2) when multiple goroutines read, write, and overwrite entries for disjoint sets of keys. In these two cases, use of a Map may significantly reduce lock contention compared to a Go map paired with a separate Mutex or RWMutex.
See https://pkg.go.dev/sync#Map
If we don't use the special use case, we should use a lock to synchronize access to the map.
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Thanks @nirs. We read on this and found that we are using special case 2 and hence, chose to proceed with sync.Map.
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a href="/RamenDR/ramen/pull/2065/commits/19efe45765f670efb4ffdcab521255d53b02a7d1" class="Link--secondary">19efe45
Signed-off-by: Annaraya Narasagond <annarayanarasagond@gmail.com>
Fixes #2048. Issue was seen when concurrent writes to the map was done. To solve the same, sync.Map is being made use of, which is thread safe.