diff --git a/mobile_packet_verifier/migrations/7_pending_data_transfer_sessions.sql b/mobile_packet_verifier/migrations/7_pending_data_transfer_sessions.sql
index 331611272..38df82101 100644
--- a/mobile_packet_verifier/migrations/7_pending_data_transfer_sessions.sql
+++ b/mobile_packet_verifier/migrations/7_pending_data_transfer_sessions.sql
@@ -1,12 +1,11 @@
 CREATE TABLE pending_data_transfer_sessions (
-       pub_key TEXT NOT NULL,
-       payer TEXT NOT NULL,
-       event_id TEXT NOT NULL,
-       uploaded_bytes BIGINT NOT NULL,
-       downloaded_bytes BIGINT NOT NULL,
-       rewardable_bytes BIGINT NOT NULL,
-       -- TODO: do we want both timestamps?
-       first_timestamp TIMESTAMPTZ NOT NULL,
-       last_timestamp TIMESTAMPTZ NOT NULL,
-       PRIMARY KEY(pub_key, payer)
+       pub_key              TEXT NOT NULL,
+       payer                TEXT NOT NULL,
+       event_id             TEXT NOT NULL,
+       uploaded_bytes       BIGINT NOT NULL,
+       downloaded_bytes     BIGINT NOT NULL,
+       rewardable_bytes     BIGINT NOT NULL,
+       recv_timestamp       TIMESTAMPTZ NOT NULL,
+       inserted_at          TIMESTAMPTZ NOT NULL,
+       PRIMARY KEY(pub_key, payer, recv_timestamp)
 );
diff --git a/mobile_packet_verifier/src/accumulate.rs b/mobile_packet_verifier/src/accumulate.rs
index e6f16777e..1b6854a54 100644
--- a/mobile_packet_verifier/src/accumulate.rs
+++ b/mobile_packet_verifier/src/accumulate.rs
@@ -76,28 +76,29 @@ pub async fn accumulate_sessions(
 
 async fn save_pending_data_transfer_session(
     conn: &mut Transaction<'_, Postgres>,
-    data_transfer_event: DataTransferEvent,
+    data_transfer_event: &DataTransferEvent,
     rewardable_bytes: u64,
-    curr_file_ts: DateTime<Utc>,
+    file_ts: DateTime<Utc>,
+    curr_ts: DateTime<Utc>,
 ) -> anyhow::Result<()> {
     sqlx::query(
         r#"
-            INSERT INTO pending_data_transfer_sessions (pub_key, event_id, payer, uploaded_bytes, downloaded_bytes, rewardable_bytes, first_timestamp, last_timestamp)
-            VALUES ($1, $2, $3, $4, $5, $6, $7, $7)
-            ON CONFLICT (pub_key, payer) DO UPDATE SET
+            INSERT INTO pending_data_transfer_sessions (pub_key, event_id, payer, uploaded_bytes, downloaded_bytes, rewardable_bytes, recv_timestamp, inserted_at)
+            VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+            ON CONFLICT (pub_key, payer, recv_timestamp) DO UPDATE SET
             uploaded_bytes = pending_data_transfer_sessions.uploaded_bytes + EXCLUDED.uploaded_bytes,
             downloaded_bytes = pending_data_transfer_sessions.downloaded_bytes + EXCLUDED.downloaded_bytes,
-            rewardable_bytes = pending_data_transfer_sessions.rewardable_bytes + EXCLUDED.rewardable_bytes,
-            last_timestamp = GREATEST(pending_data_transfer_sessions.last_timestamp, EXCLUDED.last_timestamp)
+            rewardable_bytes = pending_data_transfer_sessions.rewardable_bytes + EXCLUDED.rewardable_bytes
         "#,
     )
-    .bind(data_transfer_event.pub_key)
-    .bind(data_transfer_event.event_id)
-    .bind(data_transfer_event.payer)
+    .bind(&data_transfer_event.pub_key)
+    .bind(&data_transfer_event.event_id)
+    .bind(&data_transfer_event.payer)
     .bind(data_transfer_event.upload_bytes as i64)
     .bind(data_transfer_event.download_bytes as i64)
     .bind(rewardable_bytes as i64)
-    .bind(curr_file_ts)
+    .bind(file_ts)
+    .bind(curr_ts)
     .execute(conn)
     .await?;
     Ok(())