feat: support request-level insert WAL skipping (#9088)

* refactor: add skip_wal fields to internal write requests

Signed-off-by: WenyXu <wenymedia@gmail.com>

* chore(deps): update greptime-proto for insert skip_wal

Signed-off-by: WenyXu <wenymedia@gmail.com>

* feat(mito): support request-level WAL skipping

Signed-off-by: WenyXu <wenymedia@gmail.com>

* feat(metric-engine): handle request-level WAL policies

Signed-off-by: WenyXu <wenymedia@gmail.com>

* feat: propagate insert WAL policy through query context

Signed-off-by: WenyXu <wenymedia@gmail.com>

* feat: support session-level insert WAL policy via SET

Signed-off-by: WenyXu <wenymedia@gmail.com>

* fix(metric-engine): require uniform WAL policy in batch puts

Signed-off-by: WenyXu <wenymedia@gmail.com>

* test(metric-engine): simplify WAL policy coverage

Signed-off-by: WenyXu <wenymedia@gmail.com>

* refactor(servers): simplify gRPC hint extraction

Signed-off-by: WenyXu <wenymedia@gmail.com>

* test: flatten Mito and Metric WAL scenario orchestration

Signed-off-by: WenyXu <wenymedia@gmail.com>

* refactor: separate WAL and memtable-only mutations

Signed-off-by: WenyXu <wenymedia@gmail.com>

* refactor: carry skip-WAL policy in table insert requests

Signed-off-by: WenyXu <wenymedia@gmail.com>

* test: flatten skip-WAL policy cases

Signed-off-by: WenyXu <wenymedia@gmail.com>

* refactor: clarify WAL notifier naming

Signed-off-by: WenyXu <wenymedia@gmail.com>

* chore: pin merged skip-WAL proto revision

Signed-off-by: WenyXu <wenymedia@gmail.com>

---------

Signed-off-by: WenyXu <wenymedia@gmail.com>

src/session/src/context.rs

@@ -153,6 +153,15 @@ impl QueryContextBuilder {
         self
     }
 
+    pub fn skip_wal(mut self, skip_wal: bool) -> Self {
+        self.mutable_session_data
+            .get_or_insert_default()
+            .write()
+            .unwrap()
+            .skip_wal = skip_wal;
+        self
+    }
+
     pub fn read_preference(mut self, read_preference: ReadPreference) -> Self {
         self.mutable_session_data
             .get_or_insert_default()
@@ -348,6 +357,15 @@ impl QueryContext {
         self.mutable_session_data.write().unwrap().timezone = timezone;
     }
 
+    /// Returns whether ordinary inserts in this request should skip WAL.
+    pub fn skip_wal(&self) -> bool {
+        self.mutable_session_data.read().unwrap().skip_wal
+    }
+
+    pub fn set_skip_wal(&self, skip_wal: bool) {
+        self.mutable_session_data.write().unwrap().skip_wal = skip_wal;
+    }
+
     pub fn read_preference(&self) -> ReadPreference {
         self.mutable_session_data.read().unwrap().read_preference
     }
@@ -739,6 +757,37 @@ mod test {
         assert_eq!(fork.current_schema(), "private");
     }
 
+    #[test]
+    fn test_skip_wal_default_builder_and_fork() {
+        let default_context = QueryContext::with(DEFAULT_CATALOG_NAME, "public");
+        assert!(!default_context.skip_wal());
+        assert!(!QueryContextBuilder::default().build().skip_wal());
+        let context = QueryContextBuilder::default().skip_wal(true).build();
+        assert!(context.skip_wal());
+        let fork = context.fork();
+        assert!(fork.skip_wal());
+        fork.set_skip_wal(false);
+        assert!(context.skip_wal());
+        assert!(!fork.skip_wal());
+        context.set_skip_wal(false);
+        fork.set_skip_wal(true);
+        assert!(!context.skip_wal());
+        assert!(fork.skip_wal());
+    }
+
+    #[test]
+    fn test_skip_wal_is_not_serialized_in_query_context() {
+        let context = QueryContextBuilder::default().skip_wal(true).build();
+        let api_context: api::v1::QueryContext = context.into();
+        assert!(
+            !api_context
+                .extensions
+                .contains_key(crate::hints::INSERT_SKIP_WAL_HINT)
+        );
+        let restored: QueryContext = api_context.into();
+        assert!(!restored.skip_wal());
+    }
+
     #[test]
     fn test_api_query_context_roundtrip_with_sequences() {
         let api_ctx = api::v1::QueryContext {

src/session/src/hints.rs

@@ -23,6 +23,9 @@ pub const SUPPORT_FLIGHT_METRICS_BEFORE_BATCH_EXTENSION_KEY: &str =
     "query.support_flight_metrics_before_batch";
 pub const LIVE_ANALYZE_METRICS_EXTENSION_KEY: &str = "query.live_analyze_metrics";
 
+/// Skip WAL for this insert only; never persisted as a table option.
+pub const INSERT_SKIP_WAL_HINT: &str = "insert_skip_wal";
+
 pub const READ_PREFERENCE_HINT: &str = "read_preference";
 pub const RESERVED_EXTENSION_KEYS: [&str; 4] = [
     REMOTE_QUERY_ID_EXTENSION_KEY,

src/session/src/lib.rs

@@ -60,6 +60,8 @@ pub(crate) struct MutableInner {
     timezone: Timezone,
     query_timeout: Option<Duration>,
     read_preference: ReadPreference,
+    /// Request-level WAL policy for ordinary inserts.
+    skip_wal: bool,
     #[debug(skip)]
     pub(crate) cursors: HashMap<String, Arc<RecordBatchStreamCursor>>,
     /// Warning messages for MySQL SHOW WARNINGS support
@@ -74,6 +76,7 @@ impl Default for MutableInner {
             timezone: get_timezone(None).clone(),
             query_timeout: None,
             read_preference: ReadPreference::Leader,
+            skip_wal: false,
             cursors: HashMap::with_capacity(0),
             warnings: VecDeque::new(),
         }