HDFS-17735. [ARR] LocalResolver#getDatanodesSubcluster adapts to async rpc. #7422
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
💔 -1 overall
This message was automatically generated. |
|
💔 -1 overall
This message was automatically generated. |
|
@Hexiaoqiao @KeeProMise Sir, cc this pr when you have free time, thanks~ |
KeeProMise
reviewed
Feb 24, 2025
There was a problem hiding this comment.
Hi, @hfutatzhanghb Regarding this fix LGTM! The current implementation of the getSubclusterInfo method involves an asynchronous call to getDatanodesSubcluster(). Here's the relevant code snippet:
// Fetch the mapping asynchronously
Thread updater = new Thread(new Runnable() {
@Override
public void run() {
final MembershipStore membershipStore = getMembershipStore();
if (membershipStore == null) {
LOG.error("Cannot access the Membership store.");
return;
}
subclusterMapping = getSubclusterInfo(membershipStore);
lastUpdated = monotonicNow();
}
});
updater.start();
// Wait until initialized
if (subclusterMapping == null) {
try {
LOG.debug("Wait to get the mapping for the first time");
updater.join();
} catch (InterruptedException e) {
LOG.error("Cannot wait for the updater to finish");
}
}When subclusterMapping is null or has not been updated for a long time, an asynchronous thread is started to update subclusterMapping, and the handler thread waits until subclusterMapping is updated.
Instead of starting an asynchronous thread to update subclusterMapping when it is null or stale, and having the handler thread wait for the update to complete, we can modify the approach as follows:
- During router startup, fetch and update subclusterMapping once.
- Start a periodic thread that regularly updates subclusterMapping.
- Handler threads can read from subclusterMapping without waiting for updates, as the periodic thread ensures that subclusterMapping is kept up-to-date.
This approach ensures that the handler threads are not blocked while waiting for subclusterMapping to be updated, improving the overall performance and responsiveness of the system.
KeeProMise
approved these changes
Feb 24, 2025
@KeeProMise Sir, very nice idea. I think we can implement it in the future. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Description of PR
LocalResolver#getDatanodesSubcluster adapts to async rpc.