Changes for tracking issue 138

- create a snapshot as well as a dump
- only detect inconsistencies in the facet -> document direction
- mark index as corrupted after creating snapshot and dump
- always abort tasks on indexes marked as corrupted

index-scheduler/src/batch.rs

@@ -961,6 +961,13 @@ impl IndexScheduler {
                     .set_currently_updating_index(Some((index_uid.clone(), index.clone())));
 
                 let mut index_wtxn = index.write_txn()?;
+
+                if index.is_corrupted(&index_wtxn)? {
+                    tracing::error!("Aborting task due to corrupted index");
+                    index_wtxn.abort();
+                    return Err(crate::Error::CorruptedIndex);
+                }
+
                 let tasks = self.apply_index_operation(&mut index_wtxn, &index, op)?;
 
                 index.check_document_facet_consistency(&index_wtxn)?.check();

index-scheduler/src/error.rs

@@ -138,6 +138,8 @@ pub enum Error {
     CreateBatch(Box<Self>),
     #[error("Corrupted task queue.")]
     CorruptedTaskQueue,
+    #[error("Corrupted index.")]
+    CorruptedIndex,
     #[error(transparent)]
     TaskDatabaseUpdate(Box<Self>),
     #[error(transparent)]
@@ -192,6 +194,7 @@ impl Error {
             | Error::Anyhow(_) => true,
             Error::CreateBatch(_)
             | Error::CorruptedTaskQueue
+            | Error::CorruptedIndex
             | Error::TaskDatabaseUpdate(_)
             | Error::HeedTransaction(_) => false,
             #[cfg(test)]
@@ -242,6 +245,7 @@ impl ErrorCode for Error {
             Error::CorruptedDump => Code::Internal,
             Error::TaskDatabaseUpdate(_) => Code::Internal,
             Error::CreateBatch(_) => Code::Internal,
+            Error::CorruptedIndex => Code::Internal,
 
             // This one should never be seen by the end user
             Error::AbortedTask => Code::Internal,

index-scheduler/src/lib.rs

@@ -1219,8 +1219,48 @@ impl IndexScheduler {
             };
 
             match res {
-                Ok(_) => tracing::info!("Created a dump after failed task"),
-                Err(error) => tracing::error!(%error, "Could not create a dump after failed task"),
+                Ok(_) => tracing::info!("Created a dump after panicked task"),
+                Err(error) => {
+                    tracing::error!(%error, "Could not create a dump after panicked task")
+                }
+            }
+
+            let snap_batch = batch::Batch::SnapshotCreation(vec![Task {
+                uid: u32::MAX,
+                enqueued_at: OffsetDateTime::now_utc(),
+                started_at: Some(OffsetDateTime::now_utc()),
+                finished_at: None,
+                error: None,
+                canceled_by: None,
+                details: None,
+                status: Status::Processing,
+                kind: KindWithContent::SnapshotCreation,
+            }]);
+
+            let res = {
+                let cloned_index_scheduler = self.private_clone();
+                let handle = std::thread::Builder::new()
+                    .name(String::from("batch-operation"))
+                    .spawn(move || cloned_index_scheduler.process_batch(snap_batch))
+                    .unwrap();
+                handle.join().unwrap_or(Err(Error::ProcessBatchPanicked))
+            };
+
+            match res {
+                Ok(_) => tracing::info!("Created a snapshot after panicked task"),
+                Err(error) => {
+                    tracing::error!(%error, "Could not create a snapshot after panicked task")
+                }
+            }
+
+            {
+                if let Some(index_uid) = index_uid.as_deref() {
+                    if let Ok(index) = self.index(index_uid) {
+                        let mut index_wtxn = index.write_txn()?;
+                        index.mark_as_corrupted(&mut index_wtxn)?;
+                        index_wtxn.commit()?;
+                    }
+                }
             }
 
             let user = std::env::var("MEILI_LOUIS_PUSHOVER_USER").unwrap();
@@ -1231,7 +1271,7 @@ impl IndexScheduler {
                     "token": app,
                     "user": user,
                     "title": "Issue 138 db inconsistency",
-                    "message": "A dump has been created",
+                    "message": "Dump and snapshot created, the index has been marked as corrupted",
                 }),
             ) {
                 tracing::error!(%error, "could not send pushover")

milli/src/index.rs

@@ -67,6 +67,8 @@ pub mod main_key {
     pub const PAGINATION_MAX_TOTAL_HITS: &str = "pagination-max-total-hits";
     pub const PROXIMITY_PRECISION: &str = "proximity-precision";
     pub const EMBEDDING_CONFIGS: &str = "embedding_configs";
+
+    pub const CORRUPTED: &str = "corrupted";
 }
 
 pub mod db_name {
@@ -1557,6 +1559,14 @@ impl Index {
 
         Ok(DocumentFacetConsistency { documents, facets, facet_exists })
     }
+
+    pub fn mark_as_corrupted(&self, wtxn: &mut RwTxn<'_>) -> Result<()> {
+        Ok(self.main.remap_types::<Str, Str>().put(wtxn, main_key::CORRUPTED, "corrupted")?)
+    }
+
+    pub fn is_corrupted(&self, txn: &RoTxn<'_>) -> Result<bool> {
+        Ok(self.main.remap_types::<Str, Str>().get(txn, main_key::CORRUPTED)?.is_some())
+    }
 }
 
 pub struct DocumentFacetConsistency {
@@ -1568,20 +1578,22 @@ pub struct DocumentFacetConsistency {
 impl DocumentFacetConsistency {
     pub fn check(&self) {
         let mut inconsistencies = 0;
-        for ((field_name, facet), facet_exists) in self.facets.iter().zip(self.facet_exists.iter())
+        for ((field_name, facet), _facet_exists) in self.facets.iter().zip(self.facet_exists.iter())
         {
             if field_name == "_geo" {
                 continue;
             }
 
-            let documents = self.documents.clone() & facet_exists;
-            let missing_in_facets = &documents - facet;
+            // only check the internal ids missing in documents as it is the grave condition
+            // let documents = self.documents.clone() & facet_exists;
+            let documents = self.documents.clone();
+            // let missing_in_facets = &documents - facet;
             let missing_in_documents = facet - documents;
 
-            for id in missing_in_facets {
+            /*for id in missing_in_facets {
                 tracing::error!(id, field_name, "Missing in facets");
                 inconsistencies += 1;
-            }
+            }*/
             for id in missing_in_documents {
                 tracing::error!(id, field_name, "Missing in documents");
                 inconsistencies += 1;