From: Arik Sosman <git@arik.io>
Date: Tue, 27 Jun 2023 19:57:37 +0000 (-0400)
Subject: Fix first update lookup.
X-Git-Url: http://git.bitcoin.ninja/index.cgi?p=rapid-gossip-sync-server;a=commitdiff_plain;h=c042b6900e72fdad588fb1137644852367f2d2e6

Fix first update lookup.
---

diff --git a/src/lookup.rs b/src/lookup.rs
index 25ea854..fbd89fa 100644
--- a/src/lookup.rs
+++ b/src/lookup.rs
@@ -97,13 +97,26 @@ pub(super) async fn fetch_channel_announcements(delta_set: &mut DeltaSet, networ
 		});
 	}
 
-	println!("Obtaining channel announcements whose first channel updates had not been seen yet");
+	println!("Annotating channel announcements whose oldest channel update in a given direction occurred after the last sync");
+	/// Steps:
+	/// — Obtain all updates, distinct by (scid, direction), ordered by seen DESC // to find the oldest update in a given direction
+	/// — From those updates, select distinct by (scid), ordered by seen DESC (to obtain the newer one per direction)
+	/// This will allow us to mark the first time updates in both directions were seen
 
 	// here is where the channels whose first update in either direction occurred after
 	// `last_seen_timestamp` are added to the selection
-	let unannounced_rows = client.query("SELECT blob_signed, seen FROM (SELECT DISTINCT ON (short_channel_id) short_channel_id, blob_signed, seen FROM channel_updates ORDER BY short_channel_id ASC, seen ASC) AS first_seens WHERE first_seens.seen >= $1", &[&last_sync_timestamp_object]).await.unwrap();
-	for current_row in unannounced_rows {
-
+	let newer_oldest_directional_updates = client.query("
+		SELECT DISTINCT ON (short_channel_id) *
+		FROM (
+			SELECT DISTINCT ON (short_channel_id, direction) blob_signed
+			FROM channel_updates
+			WHERE short_channel_id = any($1)
+			ORDER BY seen ASC, short_channel_id ASC, direction ASC
+		) AS directional_last_seens
+		ORDER BY short_channel_id ASC, seen DESC
+	", &[&channel_ids]).await.unwrap();
+
+	for current_row in newer_oldest_directional_updates {
 		let blob: Vec<u8> = current_row.get("blob_signed");
 		let mut readable = Cursor::new(blob);
 		let unsigned_update = ChannelUpdate::read(&mut readable).unwrap().contents;
@@ -111,8 +124,12 @@ pub(super) async fn fetch_channel_announcements(delta_set: &mut DeltaSet, networ
 		let current_seen_timestamp_object: SystemTime = current_row.get("seen");
 		let current_seen_timestamp: u32 = current_seen_timestamp_object.duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs() as u32;
 
-		let current_channel_delta = delta_set.entry(scid).or_insert(ChannelDelta::default());
-		(*current_channel_delta).first_update_seen = Some(current_seen_timestamp);
+		if (current_seen_timestamp > last_sync_timestamp) {
+			// the newer of the two oldest seen directional updates came after last sync timestamp
+			let current_channel_delta = delta_set.entry(scid).or_insert(ChannelDelta::default());
+			// first time a channel was seen in both directions
+			(*current_channel_delta).first_bidirectional_updates_seen = Some(current_seen_timestamp);
+		}
 	}
 }