add batching in blob migration

beacon_node/beacon_chain/src/schema_change/migration_schema_v19.rs

@@ -12,24 +12,38 @@ pub fn upgrade_to_v19<T: BeaconChainTypes>(
     let column = DBColumn::BeaconBlob;
 
     debug!(log, "Migrating from v18 to v19");
-    // Iterate throught the blobs on disk.
+    // Iterate through the blobs on disk.
     for res in db.hot_db.iter_column_keys::<Vec<u8>>(column) {
         let key = res?;
         let key_col = get_key_for_col(column.as_str(), &key);
         hot_delete_ops.push(KeyValueStoreOp::DeleteKey(key_col));
         blob_keys.push(key);
     }
+
     let num_blobs = blob_keys.len();
     debug!(log, "Collected {} blob lists to migrate", num_blobs);
 
+    let batch_size = 500;
+    let mut batch = Vec::with_capacity(batch_size);
+
     for key in blob_keys {
         let next_blob = db.hot_db.get_bytes(column.as_str(), &key)?;
         if let Some(next_blob) = next_blob {
             let key_col = get_key_for_col(column.as_str(), &key);
-            db.blobs_db
-                .do_atomically(vec![KeyValueStoreOp::PutKeyValue(key_col, next_blob)])?;
+            batch.push(KeyValueStoreOp::PutKeyValue(key_col, next_blob));
+
+            if batch.len() >= batch_size {
+                db.blobs_db.do_atomically(batch.clone())?;
+                batch.clear();
+            }
         }
     }
+
+    // Process the remaining batch if it's not empty
+    if !batch.is_empty() {
+        db.blobs_db.do_atomically(batch)?;
+    }
+
     debug!(log, "Wrote {} blobs to the blobs db", num_blobs);
 
     // Delete all the blobs