why not exchange remote head

[songxiang93]

https://github.com/berty/go-orbit-db/blob/e9658b4e3af28dd8123b11fad123ba7a27e18bf5/baseorbitdb/orbitdb.go#L931

add a local head in one node and other nodes sync this of remote head。If I stop these nodes that have local head and run a new node。Other nodes that only have remote heads do not sync their remote head。So the new node that I run do not receive head and sync data from ipfs。

[gfanton]

like i say in the comment just behind, i got some unknown problem when syncing "_remoteheads".

	// >>>> @FIXME(gfanton): looks like activate this break the exchange
	// rawRemoteHeads, err := store.Cache().Get(ctx, datastore.NewKey("_remoteHeads"))
	// if err != nil && err != datastore.ErrNotFound {
	// 	return errors.Wrap(err, "unable to get data from cache")
	// }

And i'm aware that the js implementation actually sync the _remoteheads: https://github.com/orbitdb/orbit-db/blob/480ce576c848c912d15dc54fe3a7fa0304881f22/src/exchange-heads.js#L12 I need first to understand why enabling those lines on go-orbit-db implementation break things up. I will check this when I got some time.

GitHub

orbit-db/exchange-heads.js at 480ce576c848c912d15dc54fe3a7fa0304881f22 · orbitdb/orbit-db

Peer-to-Peer Databases for the Decentralized Web. Contribute to orbitdb/orbit-db development by creating an account on GitHub.

[songxiang93]

thanks! I expect your answer. @gfanton

[gfanton]

Unfortunately I still haven't had time to test it... You can try this feature by doing the following change:

modified   baseorbitdb/orbitdb.go
@@ -934,14 +934,14 @@ func (o *orbitDB) exchangeHeads(ctx context.Context, p peer.ID, store Store) err
 	}
 
 	// @FIXME(gfanton): looks like activate this break the exchange
-	// rawRemoteHeads, err := store.Cache().Get(ctx, datastore.NewKey("_remoteHeads"))
-	// if err != nil && err != datastore.ErrNotFound {
-	// 	return errors.Wrap(err, "unable to get data from cache")
-	// }
+	rawRemoteHeads, err := store.Cache().Get(ctx, datastore.NewKey("_remoteHeads"))
+	if err != nil && err != datastore.ErrNotFound {
+		return errors.Wrap(err, "unable to get data from cache")
+	}
 
 	heads := []*entry.Entry{}
 
-	for _, rawHeads := range [][]byte{rawLocalHeads} {
+	for _, rawHeads := range [][]byte{rawLocalHeads, rawRemoteHeads} {
 		if len(rawLocalHeads) > 0 {
 			var dHeads []*entry.Entry
 			err = json.Unmarshal(rawHeads, &dHeads)

If you can open a pull request with this change and add a test to show that it actually works, that would be great!

[songxiang93]

@gfanton I tested it and the problem was solved. I suggest leaving this comment open so that remote branches can be synchronized

[github-actions[bot]]

:tada: This issue has been resolved in version 1.20.0 :tada:

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