ben-manes commented on a change in pull request #14283:
URL: https://github.com/apache/pulsar/pull/14283#discussion_r806473435
##########
File path:
pulsar-metadata/src/main/java/org/apache/pulsar/metadata/cache/impl/MetadataCacheImpl.java
##########
@@ -261,12 +261,17 @@ public void invalidate(String path) {
}
@Override
- public void refresh(String path) {
+ public CompletableFuture<Void> refresh(String path) {
// Refresh object of path if only it is cached before.
- if (objCache.getIfPresent(path) != null) {
- objCache.synchronous().invalidate(path);
- objCache.synchronous().refresh(path);
- }
+ CompletableFuture<Void> promise = new CompletableFuture<>();
+ this.store.getMetadataCacheScheduler().executeOrdered(path, () -> {
+ if (objCache.getIfPresent(path) != null) {
+ objCache.synchronous().invalidate(path);
+ objCache.synchronous().refresh(path);
+ }
+ promise.complete(null);
+ });
+ return promise;
Review comment:
I'm not sure if it helps, but in [Caffeine
3.x](https://github.com/ben-manes/caffeine/releases/tag/v3.0.0) the refresh
behavior was improved to be linearizable. It also now returns te in-flight
`CompletableFuture`. You might consider upgrading.
I am also not sure why this is invalidating and refreshing. Since the value
is no longer present then the refresh is simply a cache load, and itself
delegates to `AsyncCache.get(key)`, which of course also returns that future.
You might also consider using `if (objCache.asMap().remove(key) != null) { ...
}` instead of the get/invalidate.
Trying to grok the code, I'd probably use
`objCache.asMap().computeIfPresent(key, (k, future) -> ...)` to explicitly
store a new future and return that upstream. Then it is all an atomic swap with
very clear code that localizes and shows your intent.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
