From ff68802ffc9ed964e5d3c4962e0570432d81369b Mon Sep 17 00:00:00 2001
From: Mubelotix <simon@meilisearch.com>
Date: Fri, 8 Aug 2025 11:24:04 +0200
Subject: [PATCH] Optimization A

Speeds up the "deleting tasks" subtask by 23%
---
 .../src/scheduler/process_batch.rs            | 31 +++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/crates/index-scheduler/src/scheduler/process_batch.rs b/crates/index-scheduler/src/scheduler/process_batch.rs
index c21ab27ad..7132fcee0 100644
--- a/crates/index-scheduler/src/scheduler/process_batch.rs
+++ b/crates/index-scheduler/src/scheduler/process_batch.rs
@@ -1,4 +1,5 @@
 use std::collections::{BTreeSet, HashMap, HashSet};
+use std::ops::Bound;
 use std::panic::{catch_unwind, AssertUnwindSafe};
 use std::sync::atomic::Ordering;
 
@@ -510,6 +511,29 @@ impl IndexScheduler {
         matched_tasks: &RoaringBitmap,
         progress: &Progress,
     ) -> Result<RoaringBitmap> {
+        fn consecutive_ranges<I>(iter: I) -> impl Iterator<Item = (u32, u32)>
+        where
+            I: IntoIterator<Item = u32>,
+        {
+            let mut iter = iter.into_iter().peekable();
+
+            std::iter::from_fn(move || {
+                let start = iter.next()?;
+
+                let mut end = start;
+
+                while let Some(&next) = iter.peek() {
+                    if next == end + 1 {
+                        end = next;
+                        iter.next();
+                    } else {
+                        break;
+                    }
+                }
+
+                Some((start, end))
+            })
+        }
         progress.update_progress(TaskDeletionProgress::DeletingTasksDateTime);
 
         // 1. Remove from this list the tasks that we are not allowed to delete
@@ -596,8 +620,11 @@ impl IndexScheduler {
         progress.update_progress(TaskDeletionProgress::DeletingTasks);
         let (atomic_progress, task_progress) = AtomicTaskStep::new(to_delete_tasks.len() as u32);
         progress.update_progress(task_progress);
-        for task in to_delete_tasks.iter() {
-            self.queue.tasks.all_tasks.delete(wtxn, &task)?;
+        for range in consecutive_ranges(to_delete_tasks.iter()) {
+            self.queue
+                .tasks
+                .all_tasks
+                .delete_range(wtxn, &(Bound::Included(range.0), Bound::Included(range.1)))?;
             atomic_progress.fetch_add(1, Ordering::Relaxed);
         }
         for canceled_by in affected_canceled_by {