graph: extract cache from CRUD [1] #9533

ellemouton · 2025-02-20T13:25:17Z

PART 1 only. See #9529 for the full thing

This is the 1st mini PR peeled off from this concept one which shows the final goal here which is to completely move the graph cache out of the KV CRUD layer.

This is part of #9494

Reminder about why we are doing this:

modularity (CRUD layer should be CRUD only)
when we add remote graph source, that will be managed by the layer holding the cache, which should be a separate system from the CRUD one.
When we have a new CRUD layer for the v1.75 store, we will want the 2 CRUD layers to write to the same cache. So it makes sense to move the cache to a higher layer and not be completely owned by one CRUD layer.

Rename it to kv_store.go so that we can re-use the graph.go file name later on. We will use it to house the _new_ ChannelGraph when the existing ChannelGraph is renamed to more clearly reflect its responsibilities as the CRUD layer.

coderabbitai · 2025-02-20T13:25:26Z

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In this commit, we rename the existing ChannelGraph struct to KVStore to better reflect its responsibilities as the CRUD layer. We then introduce a new ChannelGraph struct which will eventually be the layer above the CRUD layer in which we will handle cacheing and topology subscriptions. For now, however, it houses only the KVStore. This means that all calls to the KVStore will now go through this layer of indirection first. This will allow us to slowly move the graph Cache management out of the KVStore and into the new ChannelGraph layer. We introduce the new ChannelGraph and rename the old one in the same commit so that all existing call-sites don't need to change at all :)

Since we have renamed a file housing some very old code, the linter has now run on all this code for the first time. So we gotta do some clean-up work here to make it happy.

bhandras

LGTM ⚔️

bhandras · 2025-02-20T18:36:48Z

graph/db/kv_store.go

@@ -269,7 +269,7 @@ type channelMapKey struct {

 // getChannelMap loads all channel edge policies from the database and stores
 // them in a map.
-func (c *ChannelGraph) getChannelMap(edges kvdb.RBucket) (
+func (c *KVStore) getChannelMap(edges kvdb.RBucket) (


nit: receiver could also be renamed to s (as in store).

cool - since we've changed this PR to point to a side branch, I'll update this as first commit of next PR if this one gets no more comments to address, otherwise will update on next push here if more review comments 🫡

or, if it is ok, perhaps as a final commit in this cache series since this receiver change will cause maximum rebase conflicts 🙃

yyforyongyu

LGTM🦾

yyforyongyu · 2025-02-24T07:07:44Z

graph/db/graph.go

+// ChannelGraph is a layer above the graph's CRUD layer.
+//
+// NOTE: currently, this is purely a pass-through layer directly to the backing
+// KVStore. Upcoming commits will move the graph cache out of the KVStore and


yyforyongyu · 2025-02-24T07:11:19Z

docs/release-notes/release-notes-0.19.0.md

@@ -249,6 +249,8 @@ The underlying functionality between those two options remain the same.
    - [Abstract autopilot access](https://github.com/lightningnetwork/lnd/pull/9480)
    - [Abstract invoicerpc server access](https://github.com/lightningnetwork/lnd/pull/9516)
    - [Refactor to hide DB transactions](https://github.com/lightningnetwork/lnd/pull/9513)
+    - Move the graph cache out of the graph CRUD layer:


It just occurs to me that this feature is targeted for 0.20 or 0.19?

depends on when we merge the base branch into master i guess! So let's leave this here for now and then if by the time we want to merge the base branch in, if 0.19 has shipped already, then i can move this to 0.20

graph/db: rename graph.go file

2c9b74e

Rename it to kv_store.go so that we can re-use the graph.go file name later on. We will use it to house the _new_ ChannelGraph when the existing ChannelGraph is renamed to more clearly reflect its responsibilities as the CRUD layer.

ellemouton force-pushed the graph12 branch from 9221ddf to 2f9a7f8 Compare February 20, 2025 13:29

ellemouton self-assigned this Feb 20, 2025

graph/db: fix linter issues of old code

03e62d5

Since we have renamed a file housing some very old code, the linter has now run on all this code for the first time. So we gotta do some clean-up work here to make it happy.

ellemouton force-pushed the graph12 branch from 2f9a7f8 to 03e62d5 Compare February 20, 2025 13:51

ellemouton requested review from yyforyongyu and bhandras February 20, 2025 15:15

bhandras approved these changes Feb 20, 2025

View reviewed changes

ellemouton changed the base branch from master to elle-graphCacheBase February 24, 2025 06:41

yyforyongyu approved these changes Feb 24, 2025

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ellemouton merged commit 8924d3b into lightningnetwork:elle-graphCacheBase Feb 24, 2025
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graph: extract cache from CRUD [1] #9533

graph: extract cache from CRUD [1] #9533

ellemouton commented Feb 20, 2025 •

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graph: extract cache from CRUD [1] #9533

graph: extract cache from CRUD [1] #9533

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ellemouton commented Feb 20, 2025 •

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