Only check latencies once every 10 seconds with routeByLatency
#2795
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
`routeByLatency` currently checks latencies any time a server returns a MOVED or READONLY reply. When a shard is down, the ClusterClient chooses to issue the request to a random server, which returns a MOVED reply. This causes a state refresh and a latency update on all servers. This can lead to significant ping load to clusters with a large number of clients. This introduces logic to ping only once every 10 seconds, only performing a latency update on a node during the `GC` function if the latency was set later than 10 seconds ago. Fixes redis#2782
|
LGTM! |
|
Sure I'll push that change shortly. |
|
@ofekshenawa PTAL when you get a chance! |
|
@vladvildanov hoping to get some eyes here, this will help us no longer have to maintain our own fork |
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Outdated suggestions cannot be applied.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.
routeByLatencycurrently checks latencies any time a server returns a MOVED or READONLY reply. When a shard is down, the ClusterClient chooses to issue the request to a random server, which returns a MOVED reply. This causes a state refresh and a latency update on all servers. This can lead to significant ping load to clusters with a large number of clients.This introduces logic to ping only once every 10 seconds, only performing a latency update on a node during the
GCfunction if the latency was set later than 10 seconds ago.Fixes #2782
Figure: Ping behavior of the client running 21bd40a and a client running this PR. When shards are failed the current cluster client will spam pings while the fixed cluster client will only ping each server once every 10 seconds.
This shows the impact in a running large production cluster. The cluster is handling ~4M pings per second due to this behavior.
