diff --git a/collator/src/internal_queue/queue.rs b/collator/src/internal_queue/queue.rs
index 03a88b1b7..c6bd39442 100644
--- a/collator/src/internal_queue/queue.rs
+++ b/collator/src/internal_queue/queue.rs
@@ -154,12 +154,13 @@ where
             let session_state_lock = self.session_state.lock().await;
             session_state_lock.remove_diff(diff_id).await?
         };
-        if let Some(diff) = &diff {
-            let persistent_state_lock = self.persistent_state.write().await;
-            persistent_state_lock
-                .add_messages(*diff_id, diff.messages.clone())
-                .await?;
-        }
+
+        // if let Some(diff) = &diff {
+        //     let persistent_state_lock = self.persistent_state.write().await;
+        //     persistent_state_lock
+        //         .add_messages(*diff_id, diff.messages.clone())
+        //         .await?;
+        // }
         Ok(diff)
     }
 }
diff --git a/collator/src/internal_queue/shard.rs b/collator/src/internal_queue/shard.rs
index 48e3e0dbb..8712bd4bd 100644
--- a/collator/src/internal_queue/shard.rs
+++ b/collator/src/internal_queue/shard.rs
@@ -1,7 +1,7 @@
 use std::collections::BTreeMap;
 use std::sync::Arc;
 
-use everscale_types::models::BlockIdShort;
+use everscale_types::models::{BlockIdShort, ShardIdent};
 
 use crate::internal_queue::types::{EnqueuedMessage, InternalMessageKey, QueueDiff};
 use crate::tracing_targets;
@@ -33,4 +33,31 @@ impl Shard {
         }
         None
     }
+
+    // stub
+    pub fn clear_processed_messages(
+        &mut self,
+        diff_shard: ShardIdent,
+        key: &InternalMessageKey,
+    ) -> anyhow::Result<()> {
+        let mut keys_to_remove = vec![];
+
+        for (k, v) in self.outgoing_messages.iter() {
+            if k > key {
+                break;
+            }
+
+            let (chain, acc) = v.destination()?;
+            // if we proccessed message then delete it
+            if chain as i32 == diff_shard.workchain() && diff_shard.contains_account(&acc) {
+                keys_to_remove.push(k.clone());
+            }
+        }
+
+        for k in keys_to_remove {
+            self.outgoing_messages.remove(&k);
+        }
+
+        Ok(())
+    }
 }
diff --git a/collator/src/internal_queue/state/session/session_state.rs b/collator/src/internal_queue/state/session/session_state.rs
index 9c70b85b2..64fbce87b 100644
--- a/collator/src/internal_queue/state/session/session_state.rs
+++ b/collator/src/internal_queue/state/session/session_state.rs
@@ -9,6 +9,7 @@ use crate::internal_queue::shard::Shard;
 use crate::internal_queue::state::session::session_state_iterator::SessionStateIterator;
 use crate::internal_queue::state::state_iterator::{ShardRange, StateIterator};
 use crate::internal_queue::types::QueueDiff;
+use crate::tracing_targets;
 
 // FACTORY
 
@@ -98,11 +99,27 @@ impl SessionState for SessionStateStdImpl {
         for_shard_id: ShardIdent,
     ) -> Box<dyn StateIterator> {
         let shards_flat_read = self.shards_flat.read().await;
+        let mut total_messages = 0;
+
         let mut flat_shards = FastHashMap::default();
         for (shard_ident, shard_lock) in shards_flat_read.iter() {
             let shard = shard_lock.read().await;
             flat_shards.insert(*shard_ident, shard.clone());
+            total_messages += shard.outgoing_messages.len();
         }
+
+        tracing::info!(
+            target: tracing_targets::MQ,
+            "Creating iterator for shard {} with {} messages",
+            for_shard_id,
+            total_messages
+        );
+
+        let labels = [("workchain", for_shard_id.workchain().to_string())];
+
+        metrics::histogram!("tycho_session_iterator_messages_all", &labels)
+            .record(total_messages as f64);
+
         Box::new(SessionStateIterator::new(
             flat_shards,
             ranges,
@@ -228,7 +245,25 @@ impl SessionState for SessionStateStdImpl {
                 .ok_or(QueueError::ShardNotFound(diff_id.shard))?
                 .clone()
         };
-        let diff = shard_arc.write().await.remove_diff(diff_id);
+
+        // TODO clean session queue instead cleaning persistent queue
+        let diff = shard_arc.write().await.diffs.get(diff_id).cloned();
+        let processed_uptos = diff.as_ref().map(|d| &d.processed_upto);
+
+        if let Some(processed_uptos) = processed_uptos {
+            let diff_shard = diff_id.shard;
+            let flat_shards = self.shards_flat.write().await;
+
+            for processed_upto in processed_uptos {
+                let shard = flat_shards
+                    .get(processed_upto.0)
+                    .ok_or(QueueError::ShardNotFound(*processed_upto.0))?;
+
+                let mut shard_guard = shard.write().await;
+                shard_guard.clear_processed_messages(diff_shard, processed_upto.1)?;
+            }
+        }
+
         Ok(diff)
     }
 }
diff --git a/collator/src/queue_adapter.rs b/collator/src/queue_adapter.rs
index 8d9a882e9..df2182ad7 100644
--- a/collator/src/queue_adapter.rs
+++ b/collator/src/queue_adapter.rs
@@ -129,8 +129,8 @@ impl MessageQueueAdapter for MessageQueueAdapterStdImpl {
             "Committing diff to the queue"
         );
         // HACK: do not commit diff to avoid incorrect msgs set reading for collation
-        // let diff = self.queue.commit_diff(diff_id).await?;
-        let diff = None;
+        let diff = self.queue.commit_diff(diff_id).await?;
+        // let diff = None;
         Ok(diff)
     }
 
diff --git a/collator/tests/internal_queue.rs b/collator/tests/internal_queue.rs
index a8a89563f..8e71439af 100644
--- a/collator/tests/internal_queue.rs
+++ b/collator/tests/internal_queue.rs
@@ -144,28 +144,28 @@ async fn intershard_message_delivery_test() -> anyhow::Result<()> {
     adapter.commit_diff(&block_id).await?;
 
     // peek message from persistent state
-    // let mut iterator = adapter
-    //     .create_iterator(shard_id_2, from_ranges.clone(), to_ranges.clone())
-    //     .await
-    //     .unwrap();
-    //
-    // let peek_message = iterator.peek(false)?;
-    // assert!(peek_message.is_some());
-    //
-    // let next_message = iterator.next(false)?;
-    //
-    // assert!(next_message.is_some());
-    // // println!("{:?}", peek_message.unwrap().message_with_source.message.hash);
-    // let next_message = next_message.unwrap();
-    // println!("{:?}", next_message.message_with_source.message.info.dst);
-    // assert_eq!(
-    //     next_message.message_with_source.message.info.dst,
-    //     int_message.dst
-    // );
-    // assert_eq!(next_message.message_with_source.shard_id, shard_id_1);
-    //
-    // let next_message = iterator.next(false)?;
-    // assert!(next_message.is_none());
+    let mut iterator = adapter
+        .create_iterator(shard_id_2, from_ranges.clone(), to_ranges.clone())
+        .await
+        .unwrap();
+
+    let peek_message = iterator.peek(false)?;
+    assert!(peek_message.is_some());
+
+    let next_message = iterator.next(false)?;
+
+    assert!(next_message.is_some());
+    // println!("{:?}", peek_message.unwrap().message_with_source.message.hash);
+    let next_message = next_message.unwrap();
+    println!("{:?}", next_message.message_with_source.message.info.dst);
+    assert_eq!(
+        next_message.message_with_source.message.info.dst,
+        int_message.dst
+    );
+    assert_eq!(next_message.message_with_source.shard_id, shard_id_1);
+
+    let next_message = iterator.next(false)?;
+    assert!(next_message.is_none());
 
     Ok(())
 }