From: Matt Corallo <git@bluematt.me>
Date: Sat, 15 Jul 2023 07:01:16 +0000 (+0000)
Subject: Remove unused `consider_intermediate_updates` flag..optimizing query
X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=commitdiff_plain;h=58d677c291607bfed62ccdfbaf592cead530ed6c;p=rapid-gossip-sync-server

Remove unused `consider_intermediate_updates` flag..optimizing query

The `consider_intermediate_updates` flag is always set, and must be
set for correctness, so we remove it. Further, we optimize the
query that hung on it somewhat by removing an uneccessary
`ORDER BY` clause which was only neccessary if
`consider_intermediate_updates` were unset.
---

diff --git a/src/config.rs b/src/config.rs
index 2d93487..231632a 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -104,6 +104,7 @@ pub(crate) fn db_channel_update_table_creation_query() -> &'static str {
 
 pub(crate) fn db_index_creation_query() -> &'static str {
 	"
+	CREATE INDEX IF NOT EXISTS channel_updates_seen_with_id_direction_blob ON channel_updates(seen) INCLUDE (id, direction, blob_signed);
 	CREATE INDEX IF NOT EXISTS channel_updates_seen_scid ON channel_updates(seen, short_channel_id);
 	CREATE INDEX IF NOT EXISTS channel_updates_scid_dir_seen_asc ON channel_updates(short_channel_id, direction, seen);
 	CREATE INDEX IF NOT EXISTS channel_updates_scid_dir_seen_desc_with_id ON channel_updates(short_channel_id ASC, direction ASC, seen DESC) INCLUDE (id);
diff --git a/src/lib.rs b/src/lib.rs
index 1115568..37bbe4c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -136,7 +136,7 @@ fn serialize_empty_blob(current_timestamp: u64) -> Vec<u8> {
 	blob
 }
 
-async fn serialize_delta(network_graph: Arc<NetworkGraph<TestLogger>>, last_sync_timestamp: u32, consider_intermediate_updates: bool) -> SerializedResponse {
+async fn serialize_delta(network_graph: Arc<NetworkGraph<TestLogger>>, last_sync_timestamp: u32) -> SerializedResponse {
 	let (client, connection) = lookup::connect_to_db().await;
 
 	network_graph.remove_stale_channels_and_tracking();
@@ -172,7 +172,7 @@ async fn serialize_delta(network_graph: Arc<NetworkGraph<TestLogger>>, last_sync
 	let mut delta_set = DeltaSet::new();
 	lookup::fetch_channel_announcements(&mut delta_set, network_graph, &client, last_sync_timestamp).await;
 	println!("announcement channel count: {}", delta_set.len());
-	lookup::fetch_channel_updates(&mut delta_set, &client, last_sync_timestamp, consider_intermediate_updates).await;
+	lookup::fetch_channel_updates(&mut delta_set, &client, last_sync_timestamp).await;
 	println!("update-fetched channel count: {}", delta_set.len());
 	lookup::filter_delta_set(&mut delta_set);
 	println!("update-filtered channel count: {}", delta_set.len());
diff --git a/src/lookup.rs b/src/lookup.rs
index 5969b2a..0534c1c 100644
--- a/src/lookup.rs
+++ b/src/lookup.rs
@@ -201,7 +201,7 @@ pub(super) async fn fetch_channel_announcements(delta_set: &mut DeltaSet, networ
 	}
 }
 
-pub(super) async fn fetch_channel_updates(delta_set: &mut DeltaSet, client: &Client, last_sync_timestamp: u32, consider_intermediate_updates: bool) {
+pub(super) async fn fetch_channel_updates(delta_set: &mut DeltaSet, client: &Client, last_sync_timestamp: u32) {
 	let start = Instant::now();
 	let last_sync_timestamp_object = SystemTime::UNIX_EPOCH.add(Duration::from_secs(last_sync_timestamp as u64));
 
@@ -253,18 +253,11 @@ pub(super) async fn fetch_channel_updates(delta_set: &mut DeltaSet, client: &Cli
 	// (to calculate the set of mutated fields for snapshotting, where intermediate updates may
 	// have been omitted)
 
-	let mut intermediate_update_prefix = "";
-	if !consider_intermediate_updates {
-		intermediate_update_prefix = "DISTINCT ON (short_channel_id, direction)";
-	}
-
-	let query_string = format!("
-		SELECT {} id, direction, blob_signed, seen
+	let intermediate_updates = client.query("
+		SELECT id, direction, blob_signed, seen
 		FROM channel_updates
 		WHERE seen >= $1
-		ORDER BY short_channel_id ASC, direction ASC, seen DESC
-		", intermediate_update_prefix);
-	let intermediate_updates = client.query(&query_string, &[&last_sync_timestamp_object]).await.unwrap();
+		", &[&last_sync_timestamp_object]).await.unwrap();
 	println!("Fetched intermediate rows ({}): {:?}", intermediate_updates.len(), start.elapsed());
 
 	let mut previous_scid = u64::MAX;
diff --git a/src/snapshot.rs b/src/snapshot.rs
index bbe94a9..ac80079 100644
--- a/src/snapshot.rs
+++ b/src/snapshot.rs
@@ -77,7 +77,7 @@ impl Snapshotter {
 				{
 					println!("Calculating {}-day snapshot", day_range);
 					// calculate the snapshot
-					let snapshot = super::serialize_delta(network_graph_clone, current_last_sync_timestamp.clone() as u32, true).await;
+					let snapshot = super::serialize_delta(network_graph_clone, current_last_sync_timestamp.clone() as u32).await;
 
 					// persist the snapshot and update the symlink
 					let snapshot_filename = format!("snapshot__calculated-at:{}__range:{}-days__previous-sync:{}.lngossip", reference_timestamp, day_range, current_last_sync_timestamp);