fixup! For performance, switch to a row count estimate for users and devices

Author: reivilibre

crates/syn2mas/src/migration.rs

@@ -165,7 +165,7 @@ pub async fn migrate(
                 .expect("More than usize::MAX devices — unable to handle this many!")
             // Oversize the capacity, because the count is only an estimate and
             // we would like to avoid a reallocation
-            * 3 / 2,
+            * 9 / 8,
         );
 
     span.pb_set_message("migrating access tokens");
@@ -255,7 +255,7 @@ async fn migrate_users(
     let mut users_stream = pin!(synapse.read_users());
     // Oversize the capacity, because the count is only an estimate and
     // we would like to avoid a reallocation
-    let mut user_localparts_to_uuid = HashMap::with_capacity(user_count_hint * 3 / 2);
+    let mut user_localparts_to_uuid = HashMap::with_capacity(user_count_hint * 9 / 8);
     let mut synapse_admins = HashSet::new();
 
     while let Some(user_res) = users_stream.next().await {