diff --git a/postgres/migrations/V5__replica.down.sql b/postgres/migrations/V5__replica.down.sql
new file mode 100644
index 0000000..f84f17f
--- /dev/null
+++ b/postgres/migrations/V5__replica.down.sql
@@ -0,0 +1,7 @@
+DO $$
+BEGIN
+   IF EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'af_workspace_member_pkey')
+   THEN
+ALTER TABLE af_workspace_member DROP CONSTRAINT af_workspace_member_pkey;
+END IF;
+END $$;
diff --git a/postgres/migrations/V5__replica.sql b/postgres/migrations/V5__replica.sql
new file mode 100644
index 0000000..200db7c
--- /dev/null
+++ b/postgres/migrations/V5__replica.sql
@@ -0,0 +1 @@
+ALTER TABLE af_workspace_member ADD PRIMARY KEY (uid, workspace_id);
diff --git a/postgres/src/migration.rs b/postgres/src/migration.rs
index 59e9abe..09caacf 100644
--- a/postgres/src/migration.rs
+++ b/postgres/src/migration.rs
@@ -40,6 +40,9 @@ pub async fn run_down_migration(client: &Client) -> Result<(), Error> {
   let sql = include_str!("../migrations/V4__encryption.down.sql");
   client.batch_execute(sql).await?;
 
+  let sql = include_str!("../migrations/V5__replica.down.sql");
+  client.batch_execute(sql).await?;
+
   client
     .batch_execute("DROP TABLE IF EXISTS af_migration_history")
     .await?;