graph: extract cache from CRUD [6] #9555

ellemouton · 2025-02-26T12:18:12Z

** Final PR in the cache-RIP series **

This builds towards this final result by building this side branch incrementally.

In this PR, the extraction of the graphCache from the CRUD layer (KVStore) into the ChannelGraph layer is completed.
The opportunity is also taken to move the graphCache population logic out of the constructor of the ChannelGraph and into
a new Start method instead.

coderabbitai · 2025-02-26T12:18:18Z

Important

Review skipped

Auto reviews are limited to specific labels.

🏷️ Labels to auto review (1)

llm-review

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Thank you for using CodeRabbit. We offer it for free to the OSS community and would appreciate your support in helping us grow. If you find it useful, would you consider giving us a shout-out on your favorite social media?

❤️ Share

🪧 Tips

Chat

There are 3 ways to chat with CodeRabbit:

Review comments: Directly reply to a review comment made by CodeRabbit. Example:
- I pushed a fix in commit <commit_id>, please review it.
- Generate unit testing code for this file.
- Open a follow-up GitHub issue for this discussion.
Files and specific lines of code (under the "Files changed" tab): Tag @coderabbitai in a new review comment at the desired location with your query. Examples:
- @coderabbitai generate unit testing code for this file.
- @coderabbitai modularize this function.
PR comments: Tag @coderabbitai in a new PR comment to ask questions about the PR branch. For the best results, please provide a very specific query, as very limited context is provided in this mode. Examples:
- @coderabbitai gather interesting stats about this repository and render them as a table. Additionally, render a pie chart showing the language distribution in the codebase.
- @coderabbitai read src/utils.ts and generate unit testing code.
- @coderabbitai read the files in the src/scheduler package and generate a class diagram using mermaid and a README in the markdown format.
- @coderabbitai help me debug CodeRabbit configuration file.

Note: Be mindful of the bot's finite context window. It's strongly recommended to break down tasks such as reading entire modules into smaller chunks. For a focused discussion, use review comments to chat about specific files and their changes, instead of using the PR comments.

CodeRabbit Commands (Invoked using PR comments)

@coderabbitai pause to pause the reviews on a PR.
@coderabbitai resume to resume the paused reviews.
@coderabbitai review to trigger an incremental review. This is useful when automatic reviews are disabled for the repository.
@coderabbitai full review to do a full review from scratch and review all the files again.
@coderabbitai summary to regenerate the summary of the PR.
@coderabbitai generate docstrings to generate docstrings for this PR.
@coderabbitai resolve resolve all the CodeRabbit review comments.
@coderabbitai configuration to show the current CodeRabbit configuration for the repository.
@coderabbitai help to get help.

Other keywords and placeholders

Add @coderabbitai ignore anywhere in the PR description to prevent this PR from being reviewed.
Add @coderabbitai summary to generate the high-level summary at a specific location in the PR description.
Add @coderabbitai anywhere in the PR title to generate the title automatically.

CodeRabbit Configuration File (`.coderabbit.yaml`)

You can programmatically configure CodeRabbit by adding a .coderabbit.yaml file to the root of your repository.
Please see the configuration documentation for more information.
If your editor has YAML language server enabled, you can add the path at the top of this file to enable auto-completion and validation: # yaml-language-server: $schema=https://coderabbit.ai/integrations/schema.v2.json

Documentation and Community

Visit our Documentation for detailed information on how to use CodeRabbit.
Join our Discord Community to get help, request features, and share feedback.
Follow us on X/Twitter for updates and announcements.

bhandras

LGTM 🍫

graph/db/kv_store.go

graph/db/graph.go

bhandras · 2025-02-27T18:28:09Z

graph/db/graph.go

@@ -119,6 +88,13 @@ func (c *ChannelGraph) Start() error {
 	log.Debugf("ChannelGraph starting")
 	defer log.Debug("ChannelGraph started")

+	if c.graphCache != nil {
+		if err := c.populateCache(); err != nil {
+			return fmt.Errorf("could not populate the graph "+


nit: the started flag remains dirty, but i think that's okay since we likely won't try to start the same graph instance again.

graph/db/graph.go

GustavoStingelin · 2025-02-28T00:21:54Z

graph/db/graph.go

+	if !c.started.CompareAndSwap(false, true) {
+		return nil
+	}
+	log.Debugf("ChannelGraph starting")


Suggested change

log.Debugf("ChannelGraph starting")

log.Debug("ChannelGraph starting")

Do we have a pattern for choosing the format when using a simple string, or does it not matter?

As long as it conveys useful info to the user

GustavoStingelin · 2025-02-28T00:43:20Z

graph/db/graph.go

+	started atomic.Bool
+	stopped atomic.Bool


Why do we need two booleans (started and stopped) to track the state? Wouldn't a single atomic boolean be enough? Using just one (active, for example) would simplify the logic and prevent inconsistent states like started = true and stopped = true at the same time.

these should be read as "has this service ever been started" and "has this service ever been stopped" . So both being true is legit.

We use this pattern throughout the code-base. Services are not restartable

Why do we need two booleans (started and stopped) to track the state?

Very good question! In addition to Elle's comment I do think using one var makes things easier as it prevents inconsistent states, we may consider changing it one day but it's not our priority atm, plus it's working fine so far.

We do this in preparation for moving channel cache population logic out of the constructor and into the Start method. We also will later on (when topology subscription is moved to the ChannelGraph), have a goroutine that will need to be kicked off and stopped.

…ction In this commit, we move the graph cache population logic out of the ChannelGraph constructor and into its Start method instead.

yyforyongyu

🧹

yyforyongyu · 2025-02-28T08:43:29Z

graph/db/kv_store.go

@@ -184,13 +184,12 @@ const (
 type KVStore struct {
 	db kvdb.Backend

-	// cacheMu guards all caches (rejectCache, chanCache, graphCache). If
+	// cacheMu guards all caches (rejectCache and chanCache). If


yyforyongyu · 2025-02-28T08:47:11Z

graph/db/graph.go

 	}

 	// The graph cache can be turned off (e.g. for mobile users) for a
 	// speed/memory usage tradeoff.
-	graphCache := NewGraphCache(opts.preAllocCacheNumNodes)


yyforyongyu · 2025-02-28T08:52:51Z

graph/db/graph.go

+	started atomic.Bool
+	stopped atomic.Bool


Why do we need two booleans (started and stopped) to track the state?

Very good question! In addition to Elle's comment I do think using one var makes things easier as it prevents inconsistent states, we may consider changing it one day but it's not our priority atm, plus it's working fine so far.

yyforyongyu · 2025-02-28T08:55:10Z

btw the itest update_channel_policy is now flaky - I think for intermediate PRs merged to a side branch it's fine, but eventually when we merge them back to the master we would need to make sure the CI stays green🙏

ellemouton · 2025-02-28T09:03:29Z

btw the itest update_channel_policy is now flaky

Investigating 👍 ~~(looks like [5] introduced it)~~ nvm - i think it was pre-existing. I'm going to merge this into the side branch and then open 1 more PR to the side branch to fix the flake

ellemouton added the graph label Feb 26, 2025

ellemouton self-assigned this Feb 26, 2025

ellemouton force-pushed the graph17 branch 2 times, most recently from 7505858 to bb3af46 Compare February 27, 2025 12:02

ellemouton changed the base branch from elle-graphCacheBase2 to elle-graphCacheBase February 27, 2025 12:02

ellemouton force-pushed the graph17 branch from bb3af46 to 9c39333 Compare February 27, 2025 12:09

ellemouton force-pushed the elle-graphCacheBase branch from 5eb96dc to 3ce4799 Compare February 27, 2025 13:22

graph/db: completely remove cache from KVStore

d053b8a

ellemouton force-pushed the graph17 branch from 9c39333 to 1c62c28 Compare February 27, 2025 13:26

ellemouton requested review from yyforyongyu and bhandras February 27, 2025 14:44

bhandras approved these changes Feb 27, 2025

View reviewed changes

GustavoStingelin reviewed Feb 28, 2025

View reviewed changes

ellemouton added 2 commits February 28, 2025 09:47

graph/db: populate the graph cache in Start instead of during constru…

2a0fb5d

…ction In this commit, we move the graph cache population logic out of the ChannelGraph constructor and into its Start method instead.

ellemouton force-pushed the graph17 branch from 1c62c28 to 2a0fb5d Compare February 28, 2025 07:47

yyforyongyu approved these changes Feb 28, 2025

View reviewed changes

ellemouton merged commit 1293f2e into lightningnetwork:elle-graphCacheBase Feb 28, 2025
31 of 35 checks passed

ellemouton deleted the graph17 branch February 28, 2025 11:19

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

graph: extract cache from CRUD [6] #9555

graph: extract cache from CRUD [6] #9555

ellemouton commented Feb 26, 2025 •

edited

Loading

coderabbitai bot commented Feb 26, 2025

Review skipped

Chat

CodeRabbit Commands (Invoked using PR comments)

Other keywords and placeholders

CodeRabbit Configuration File (`.coderabbit.yaml`)

Documentation and Community

bhandras left a comment

bhandras Feb 27, 2025

GustavoStingelin Feb 28, 2025

GustavoStingelin Feb 28, 2025

ellemouton Feb 28, 2025

GustavoStingelin Feb 28, 2025

ellemouton Feb 28, 2025

yyforyongyu Feb 28, 2025

yyforyongyu left a comment

yyforyongyu Feb 28, 2025

yyforyongyu Feb 28, 2025

yyforyongyu Feb 28, 2025

yyforyongyu commented Feb 28, 2025

ellemouton commented Feb 28, 2025 •

edited

Loading

	log.Debugf("ChannelGraph starting")
	log.Debug("ChannelGraph starting")

graph: extract cache from CRUD [6] #9555

graph: extract cache from CRUD [6] #9555

Conversation

ellemouton commented Feb 26, 2025 • edited Loading

coderabbitai bot commented Feb 26, 2025

Review skipped

Chat

CodeRabbit Commands (Invoked using PR comments)

Other keywords and placeholders

CodeRabbit Configuration File (.coderabbit.yaml)

Documentation and Community

bhandras left a comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

yyforyongyu left a comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

yyforyongyu commented Feb 28, 2025

ellemouton commented Feb 28, 2025 • edited Loading

ellemouton commented Feb 26, 2025 •

edited

Loading

CodeRabbit Configuration File (`.coderabbit.yaml`)

ellemouton commented Feb 28, 2025 •

edited

Loading