Drop overly optimistic index

The `channel_updates_id_with_scid_dir_blob` index allows the
intermediate-row-fetching logic to be index-only, but there's very
little reason to do so - we now use subqueries to build the exact
set of rows we want, by id, and then fetch various colums. Having
an index that lets us look up those columns without hitting the
regular table is fine, but there's not a ton of cost to hitting the
table by primary key and maintaining yet another index isn't free.

diff --git a/src/config.rs b/src/config.rs
index 231632ab7d93c758a21f475ea72b9658a3f7bf97..6249940138c758575484e0249869a3ababdd683a 100644 (file)
--- a/src/config.rs
+++ b/src/config.rs
@@ -15,7 +15,7 @@ use lightning::util::ser::Readable;
 use lightning_block_sync::http::HttpEndpoint;
 use tokio_postgres::Config;
 
-pub(crate) const SCHEMA_VERSION: i32 = 10;
+pub(crate) const SCHEMA_VERSION: i32 = 11;
 pub(crate) const SNAPSHOT_CALCULATION_INTERVAL: u32 = 3600 * 24; // every 24 hours, in seconds
 /// If the last update in either direction was more than six days ago, we send a reminder
 /// That reminder may be either in the form of a channel announcement, or in the form of empty
@@ -108,7 +108,6 @@ pub(crate) fn db_index_creation_query() -> &'static str {
        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);
-       CREATE INDEX IF NOT EXISTS channel_updates_id_with_scid_dir_blob ON channel_updates(id) INCLUDE (short_channel_id, direction, blob_signed);
        CREATE UNIQUE INDEX IF NOT EXISTS channel_updates_key ON channel_updates (short_channel_id, direction, timestamp);
        "
 }
@@ -236,6 +235,12 @@ pub(crate) async fn upgrade_db(schema: i32, client: &mut tokio_postgres::Client)
                tx.execute("UPDATE config SET db_schema = 10 WHERE id = 1", &[]).await.unwrap();
                tx.commit().await.unwrap();
        }
+       if schema >= 1 && schema <= 10 {
+               let tx = client.transaction().await.unwrap();
+               tx.execute("DROP INDEX channel_updates_id_with_scid_dir_blob", &[]).await.unwrap();
+               tx.execute("UPDATE config SET db_schema = 11 WHERE id = 1", &[]).await.unwrap();
+               tx.commit().await.unwrap();
+       }
        if schema <= 1 || schema > SCHEMA_VERSION {
                panic!("Unknown schema in db: {}, we support up to {}", schema, SCHEMA_VERSION);
        }