diff --git a/src/mito2/src/metrics.rs b/src/mito2/src/metrics.rs
index bd5920b3cb..855ba9ddf6 100644
--- a/src/mito2/src/metrics.rs
+++ b/src/mito2/src/metrics.rs
@@ -44,4 +44,6 @@ pub const WRITE_REJECT_TOTAL: &str = "mito.write.reject_total";
 pub const WRITE_STAGE_ELAPSED: &str = "mito.write.stage_elapsed";
 /// Stage label.
 pub const STAGE_LABEL: &str = "stage";
+/// Counter of rows to write.
+pub const WRITE_ROWS_TOTAL: &str = "mito.write.rows_total";
 // ------ End of write related metrics
diff --git a/src/mito2/src/region_write_ctx.rs b/src/mito2/src/region_write_ctx.rs
index 8e83a6442a..5270ceec32 100644
--- a/src/mito2/src/region_write_ctx.rs
+++ b/src/mito2/src/region_write_ctx.rs
@@ -15,7 +15,7 @@
 use std::mem;
 use std::sync::Arc;
 
-use api::v1::{Mutation, Rows, WalEntry};
+use api::v1::{Mutation, OpType, Rows, WalEntry};
 use common_query::Output;
 use snafu::ResultExt;
 use store_api::logstore::LogStore;
@@ -92,6 +92,14 @@ pub(crate) struct RegionWriteCtx {
     ///
     /// The i-th notify is for i-th mutation.
     notifiers: Vec<WriteNotify>,
+    /// The write operation is failed and we should not write to the mutable memtable.
+    failed: bool,
+
+    // Metrics:
+    /// Rows to put.
+    pub(crate) put_num: usize,
+    /// Rows to delete.
+    pub(crate) delete_num: usize,
 }
 
 impl RegionWriteCtx {
@@ -112,6 +120,9 @@ impl RegionWriteCtx {
             next_entry_id: last_entry_id + 1,
             wal_entry: WalEntry::default(),
             notifiers: Vec::new(),
+            failed: false,
+            put_num: 0,
+            delete_num: 0,
         }
     }
 
@@ -130,6 +141,13 @@ impl RegionWriteCtx {
 
         // Increase sequence number.
         self.next_sequence += num_rows as u64;
+
+        // Update metrics.
+        match OpType::from_i32(op_type) {
+            Some(OpType::Delete) => self.delete_num += num_rows,
+            Some(OpType::Put) => self.put_num += num_rows,
+            None => (),
+        }
     }
 
     /// Encode and add WAL entry to the writer.
@@ -153,6 +171,9 @@ impl RegionWriteCtx {
         for notify in &mut self.notifiers {
             notify.err = Some(err.clone());
         }
+
+        // Fail the whole write operation.
+        self.failed = true;
     }
 
     /// Updates next entry id.
@@ -164,6 +185,10 @@ impl RegionWriteCtx {
     pub(crate) fn write_memtable(&mut self) {
         debug_assert_eq!(self.notifiers.len(), self.wal_entry.mutations.len());
 
+        if self.failed {
+            return;
+        }
+
         let mutable = &self.version.memtables.mutable;
         // Takes mutations from the wal entry.
         let mutations = mem::take(&mut self.wal_entry.mutations);
diff --git a/src/mito2/src/worker/handle_write.rs b/src/mito2/src/worker/handle_write.rs
index de6b6a5c5e..873ef726fb 100644
--- a/src/mito2/src/worker/handle_write.rs
+++ b/src/mito2/src/worker/handle_write.rs
@@ -24,7 +24,10 @@ use store_api::metadata::RegionMetadata;
 use store_api::storage::RegionId;
 
 use crate::error::{RejectWriteSnafu, Result};
-use crate::metrics::{STAGE_LABEL, WRITE_REJECT_TOTAL, WRITE_STAGE_ELAPSED, WRITE_STALL_TOTAL};
+use crate::metrics::{
+    STAGE_LABEL, TYPE_LABEL, WRITE_REJECT_TOTAL, WRITE_ROWS_TOTAL, WRITE_STAGE_ELAPSED,
+    WRITE_STALL_TOTAL,
+};
 use crate::region_write_ctx::RegionWriteCtx;
 use crate::request::{SenderWriteRequest, WriteRequest};
 use crate::worker::RegionWorkerLoop;
@@ -80,13 +83,19 @@ impl<S: LogStore> RegionWorkerLoop<S> {
             }
         }
 
+        let (mut put_rows, mut delete_rows) = (0, 0);
         // Write to memtables.
         {
             let _timer = timer!(WRITE_STAGE_ELAPSED, &[(STAGE_LABEL, "write_memtable")]);
             for mut region_ctx in region_ctxs.into_values() {
                 region_ctx.write_memtable();
+                put_rows += region_ctx.put_num;
+                delete_rows += region_ctx.delete_num;
             }
         }
+
+        counter!(WRITE_ROWS_TOTAL, put_rows as u64, TYPE_LABEL => "put");
+        counter!(WRITE_ROWS_TOTAL, delete_rows as u64, TYPE_LABEL => "delete");
     }
 }
 
diff --git a/src/store-api/src/region_request.rs b/src/store-api/src/region_request.rs
index 9d608f2077..04251b81ae 100644
--- a/src/store-api/src/region_request.rs
+++ b/src/store-api/src/region_request.rs
@@ -30,7 +30,6 @@ use crate::storage::{ColumnId, RegionId, ScanRequest};
 
 #[derive(Debug, IntoStaticStr)]
 pub enum RegionRequest {
-    // TODO: rename to InsertRequest
     Put(RegionPutRequest),
     Delete(RegionDeleteRequest),
     Create(RegionCreateRequest),