diff --git a/migrations/0056_personal_read_state.sql b/migrations/0056_personal_read_state.sql
index 4ea1b7e881..2d51ae8cf0 100644
--- a/migrations/0056_personal_read_state.sql
+++ b/migrations/0056_personal_read_state.sql
@@ -60,5 +60,10 @@ ALTER TABLE event_mentions ADD COLUMN received_at TIMESTAMPTZ, ADD COLUMN root_i
 CREATE INDEX idx_event_mentions_scope_received
     ON event_mentions (community_id, pubkey_hex, channel_id, root_id, received_at);
 
+-- idx_thread_metadata_window (0049) leads with the same columns. With both,
+-- the planner can take this narrower index for a thread's latest reply and
+-- then sort every reply in the thread instead of reading the first row.
+DROP INDEX IF EXISTS idx_thread_metadata_root;
+
 SELECT attach_community_write_fence('personal_read_accounts');
 SELECT attach_community_write_fence('personal_read_frontiers');
diff --git a/schema/schema.sql b/schema/schema.sql
index 4c4378b66e..aaff2018df 100644
--- a/schema/schema.sql
+++ b/schema/schema.sql
@@ -576,7 +576,6 @@ CREATE TABLE thread_metadata (
 );
 
 CREATE INDEX idx_thread_metadata_parent ON thread_metadata (community_id, parent_event_id);
-CREATE INDEX idx_thread_metadata_root ON thread_metadata (community_id, root_event_id);
 CREATE INDEX idx_thread_metadata_window
     ON thread_metadata (community_id, root_event_id, event_created_at DESC, event_id ASC);
 CREATE INDEX idx_thread_metadata_channel_depth