Merge #4053

4053: Fix the stats of the documents deletion by filter r=Kerollmops a=irevoire

# Pull Request

The issue was that the operation « DocumentDeletionByFilter » was not declared as an index operation. That means the index stats were not reprocessed after the application of the operation.

## Related issue
Fixes #4018

## What does this PR do?
- Move the `DocumentDeletionByFilter` internal operation into the category of the `IndexOperation`. This means that the stats will automatically be re-processed after a batch is processed.
- Update a test to ensure that the stats are valid after each operation

## PR checklist
Please check if your PR fulfills the following requirements:
- [x] Does this PR fix an existing issue, or have you listed the changes applied in the PR description (and why they are needed)?
- [x] Have you read the contributing guidelines?
- [x] Have you made sure that the title is accurate and descriptive of the changes?

Thank you so much for contributing to Meilisearch!


Co-authored-by: Tamo <tamo@meilisearch.com>

index-scheduler/src/batch.rs

@@ -67,10 +67,6 @@ pub(crate) enum Batch {
         op: IndexOperation,
         must_create_index: bool,
     },
-    IndexDocumentDeletionByFilter {
-        index_uid: String,
-        task: Task,
-    },
     IndexCreation {
         index_uid: String,
         primary_key: Option<String>,
@@ -114,6 +110,10 @@ pub(crate) enum IndexOperation {
         documents: Vec<Vec<String>>,
         tasks: Vec<Task>,
     },
+    IndexDocumentDeletionByFilter {
+        index_uid: String,
+        task: Task,
+    },
     DocumentClear {
         index_uid: String,
         tasks: Vec<Task>,
@@ -155,7 +155,6 @@ impl Batch {
             | Batch::TaskDeletion(task)
             | Batch::Dump(task)
             | Batch::IndexCreation { task, .. }
-            | Batch::IndexDocumentDeletionByFilter { task, .. }
             | Batch::IndexUpdate { task, .. } => vec![task.uid],
             Batch::SnapshotCreation(tasks) | Batch::IndexDeletion { tasks, .. } => {
                 tasks.iter().map(|task| task.uid).collect()
@@ -167,6 +166,7 @@ impl Batch {
                 | IndexOperation::DocumentClear { tasks, .. } => {
                     tasks.iter().map(|task| task.uid).collect()
                 }
+                IndexOperation::IndexDocumentDeletionByFilter { task, .. } => vec![task.uid],
                 IndexOperation::SettingsAndDocumentOperation {
                     document_import_tasks: tasks,
                     settings_tasks: other,
@@ -194,8 +194,7 @@ impl Batch {
             IndexOperation { op, .. } => Some(op.index_uid()),
             IndexCreation { index_uid, .. }
             | IndexUpdate { index_uid, .. }
-            | IndexDeletion { index_uid, .. }
-            | IndexDocumentDeletionByFilter { index_uid, .. } => Some(index_uid),
+            | IndexDeletion { index_uid, .. } => Some(index_uid),
         }
     }
 }
@@ -205,6 +204,7 @@ impl IndexOperation {
         match self {
             IndexOperation::DocumentOperation { index_uid, .. }
             | IndexOperation::DocumentDeletion { index_uid, .. }
+            | IndexOperation::IndexDocumentDeletionByFilter { index_uid, .. }
             | IndexOperation::DocumentClear { index_uid, .. }
             | IndexOperation::Settings { index_uid, .. }
             | IndexOperation::DocumentClearAndSetting { index_uid, .. }
@@ -239,9 +239,12 @@ impl IndexScheduler {
                 let task = self.get_task(rtxn, id)?.ok_or(Error::CorruptedTaskQueue)?;
                 match &task.kind {
                     KindWithContent::DocumentDeletionByFilter { index_uid, .. } => {
-                        Ok(Some(Batch::IndexDocumentDeletionByFilter {
-                            index_uid: index_uid.clone(),
-                            task,
+                        Ok(Some(Batch::IndexOperation {
+                            op: IndexOperation::IndexDocumentDeletionByFilter {
+                                index_uid: index_uid.clone(),
+                                task,
+                            },
+                            must_create_index: false,
                         }))
                     }
                     _ => unreachable!(),
@@ -896,51 +899,6 @@ impl IndexScheduler {
 
                 Ok(tasks)
             }
-            Batch::IndexDocumentDeletionByFilter { mut task, index_uid: _ } => {
-                let (index_uid, filter) =
-                    if let KindWithContent::DocumentDeletionByFilter { index_uid, filter_expr } =
-                        &task.kind
-                    {
-                        (index_uid, filter_expr)
-                    } else {
-                        unreachable!()
-                    };
-                let index = {
-                    let rtxn = self.env.read_txn()?;
-                    self.index_mapper.index(&rtxn, index_uid)?
-                };
-                let deleted_documents = delete_document_by_filter(filter, index);
-                let original_filter = if let Some(Details::DocumentDeletionByFilter {
-                    original_filter,
-                    deleted_documents: _,
-                }) = task.details
-                {
-                    original_filter
-                } else {
-                    // In the case of a `documentDeleteByFilter` the details MUST be set
-                    unreachable!();
-                };
-
-                match deleted_documents {
-                    Ok(deleted_documents) => {
-                        task.status = Status::Succeeded;
-                        task.details = Some(Details::DocumentDeletionByFilter {
-                            original_filter,
-                            deleted_documents: Some(deleted_documents),
-                        });
-                    }
-                    Err(e) => {
-                        task.status = Status::Failed;
-                        task.details = Some(Details::DocumentDeletionByFilter {
-                            original_filter,
-                            deleted_documents: Some(0),
-                        });
-                        task.error = Some(e.into());
-                    }
-                }
-
-                Ok(vec![task])
-            }
             Batch::IndexCreation { index_uid, primary_key, task } => {
                 let wtxn = self.env.write_txn()?;
                 if self.index_mapper.exists(&wtxn, &index_uid)? {
@@ -1299,6 +1257,47 @@ impl IndexScheduler {
 
                 Ok(tasks)
             }
+            IndexOperation::IndexDocumentDeletionByFilter { mut task, index_uid: _ } => {
+                let filter =
+                    if let KindWithContent::DocumentDeletionByFilter { filter_expr, .. } =
+                        &task.kind
+                    {
+                        filter_expr
+                    } else {
+                        unreachable!()
+                    };
+                let deleted_documents = delete_document_by_filter(index_wtxn, filter, index);
+                let original_filter = if let Some(Details::DocumentDeletionByFilter {
+                    original_filter,
+                    deleted_documents: _,
+                }) = task.details
+                {
+                    original_filter
+                } else {
+                    // In the case of a `documentDeleteByFilter` the details MUST be set
+                    unreachable!();
+                };
+
+                match deleted_documents {
+                    Ok(deleted_documents) => {
+                        task.status = Status::Succeeded;
+                        task.details = Some(Details::DocumentDeletionByFilter {
+                            original_filter,
+                            deleted_documents: Some(deleted_documents),
+                        });
+                    }
+                    Err(e) => {
+                        task.status = Status::Failed;
+                        task.details = Some(Details::DocumentDeletionByFilter {
+                            original_filter,
+                            deleted_documents: Some(0),
+                        });
+                        task.error = Some(e.into());
+                    }
+                }
+
+                Ok(vec![task])
+            }
             IndexOperation::Settings { index_uid: _, settings, mut tasks } => {
                 let indexer_config = self.index_mapper.indexer_config();
                 let mut builder = milli::update::Settings::new(index_wtxn, index, indexer_config);
@@ -1498,23 +1497,22 @@ impl IndexScheduler {
     }
 }
 
-fn delete_document_by_filter(filter: &serde_json::Value, index: Index) -> Result<u64> {
+fn delete_document_by_filter<'a>(
+    wtxn: &mut RwTxn<'a, '_>,
+    filter: &serde_json::Value,
+    index: &'a Index,
+) -> Result<u64> {
     let filter = Filter::from_json(filter)?;
     Ok(if let Some(filter) = filter {
-        let mut wtxn = index.write_txn()?;
-
-        let candidates = filter.evaluate(&wtxn, &index).map_err(|err| match err {
+        let candidates = filter.evaluate(wtxn, index).map_err(|err| match err {
             milli::Error::UserError(milli::UserError::InvalidFilter(_)) => {
                 Error::from(err).with_custom_error_code(Code::InvalidDocumentFilter)
             }
             e => e.into(),
         })?;
-        let mut delete_operation = DeleteDocuments::new(&mut wtxn, &index)?;
+        let mut delete_operation = DeleteDocuments::new(wtxn, index)?;
         delete_operation.delete_documents(&candidates);
-        let deleted_documents =
-            delete_operation.execute().map(|result| result.deleted_documents)?;
-        wtxn.commit()?;
-        deleted_documents
+        delete_operation.execute().map(|result| result.deleted_documents)?
     } else {
         0
     })

meilisearch/tests/documents/delete_documents.rs

@@ -154,6 +154,19 @@ async fn delete_document_by_filter() {
         )
         .await;
     index.wait_task(1).await;
+
+    let (stats, _) = index.stats().await;
+    snapshot!(json_string!(stats), @r###"
+    {
+      "numberOfDocuments": 4,
+      "isIndexing": false,
+      "fieldDistribution": {
+        "color": 3,
+        "id": 4
+      }
+    }
+    "###);
+
     let (response, code) =
         index.delete_document_by_filter(json!({ "filter": "color = blue"})).await;
     snapshot!(code, @"202 Accepted");
@@ -188,6 +201,18 @@ async fn delete_document_by_filter() {
     }
     "###);
 
+    let (stats, _) = index.stats().await;
+    snapshot!(json_string!(stats), @r###"
+    {
+      "numberOfDocuments": 2,
+      "isIndexing": false,
+      "fieldDistribution": {
+        "color": 1,
+        "id": 2
+      }
+    }
+    "###);
+
     let (documents, code) = index.get_all_documents(GetAllDocumentsOptions::default()).await;
     snapshot!(code, @"200 OK");
     snapshot!(json_string!(documents), @r###"
@@ -241,6 +266,18 @@ async fn delete_document_by_filter() {
     }
     "###);
 
+    let (stats, _) = index.stats().await;
+    snapshot!(json_string!(stats), @r###"
+    {
+      "numberOfDocuments": 1,
+      "isIndexing": false,
+      "fieldDistribution": {
+        "color": 1,
+        "id": 1
+      }
+    }
+    "###);
+
     let (documents, code) = index.get_all_documents(GetAllDocumentsOptions::default()).await;
     snapshot!(code, @"200 OK");
     snapshot!(json_string!(documents), @r###"