Add UpdatesOnly query option to fetch data for only changed keys #23042
Conversation
This file contains hidden or 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
As mentioned long ago (and roughly outlined) in hashicorp#2791, a limitation on blocking queries is that all K/V entries matching that prefix are returned, even though only 1 key may have changed. This diff adds a new `UpdatesOnly` option, that when set, introduces server-side filtering to remove all keys/entries (from a `Keys()` or `List()` query) that have an old `ModifyIndex`. It uses `MinQueryIndex` as the threshold here, which follows the effective serialization/deserialization chain: `WaitIndex` --> `index` --> `MinQueryIndex`. - `WaitIndex` being the client-side parameter, determining the index the "client" waits for on a blocking query - `index` being the serialized HTTP query parameter representing the `WaitIndex` - `MinQueryIndex` being the server-side struct (deserialized result of `index`) While we (potentially?) wait for the streaming backend: https://developer.hashicorp.com/consul/api-docs/features/blocking#streaming-backend to be implemented for KV endpoints, this can be a good stop-gap solution to enable in-memory, incremental scans or queries over a prefix.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
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Outdated suggestions cannot be applied.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.
Resurrection of #22108