diff --git a/crates/syn2mas/.sqlx/query-026adeffc646b41ebc096bb874d110039b9a4a0425fd566e401f56ea215de0dd.json b/crates/syn2mas/.sqlx/query-026adeffc646b41ebc096bb874d110039b9a4a0425fd566e401f56ea215de0dd.json
new file mode 100644
index 000000000..fa5f442ed
--- /dev/null
+++ b/crates/syn2mas/.sqlx/query-026adeffc646b41ebc096bb874d110039b9a4a0425fd566e401f56ea215de0dd.json
@@ -0,0 +1,18 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "\n            INSERT INTO syn2mas__upstream_oauth_links\n            (upstream_oauth_link_id, user_id, upstream_oauth_provider_id, subject, created_at)\n            SELECT * FROM UNNEST($1::UUID[], $2::UUID[], $3::UUID[], $4::TEXT[], $5::TIMESTAMP WITH TIME ZONE[])\n            ",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Left": [
+        "UuidArray",
+        "UuidArray",
+        "UuidArray",
+        "TextArray",
+        "TimestamptzArray"
+      ]
+    },
+    "nullable": []
+  },
+  "hash": "026adeffc646b41ebc096bb874d110039b9a4a0425fd566e401f56ea215de0dd"
+}
diff --git a/crates/syn2mas/.sqlx/query-d79fd99ebed9033711f96113005096c848ae87c43b6430246ef3b6a1dc6a7a32.json b/crates/syn2mas/.sqlx/query-d79fd99ebed9033711f96113005096c848ae87c43b6430246ef3b6a1dc6a7a32.json
deleted file mode 100644
index f6ac32781..000000000
--- a/crates/syn2mas/.sqlx/query-d79fd99ebed9033711f96113005096c848ae87c43b6430246ef3b6a1dc6a7a32.json
+++ /dev/null
@@ -1,18 +0,0 @@
-{
-  "db_name": "PostgreSQL",
-  "query": "\n                    INSERT INTO syn2mas__upstream_oauth_links\n                    (upstream_oauth_link_id, user_id, upstream_oauth_provider_id, subject, created_at)\n                    SELECT * FROM UNNEST($1::UUID[], $2::UUID[], $3::UUID[], $4::TEXT[], $5::TIMESTAMP WITH TIME ZONE[])\n                    ",
-  "describe": {
-    "columns": [],
-    "parameters": {
-      "Left": [
-        "UuidArray",
-        "UuidArray",
-        "UuidArray",
-        "TextArray",
-        "TimestamptzArray"
-      ]
-    },
-    "nullable": []
-  },
-  "hash": "d79fd99ebed9033711f96113005096c848ae87c43b6430246ef3b6a1dc6a7a32"
-}
diff --git a/crates/syn2mas/src/mas_writer/mod.rs b/crates/syn2mas/src/mas_writer/mod.rs
index cbb4ad3b0..0f7ccf715 100644
--- a/crates/syn2mas/src/mas_writer/mod.rs
+++ b/crates/syn2mas/src/mas_writer/mod.rs
@@ -478,6 +478,46 @@ pub struct MasNewUpstreamOauthLink {
     pub created_at: DateTime<Utc>,
 }
 
+impl WriteBatch for MasNewUpstreamOauthLink {
+    async fn write_batch(conn: &mut PgConnection, batch: Vec<Self>) -> Result<(), Error> {
+        let mut link_ids: Vec<Uuid> = Vec::with_capacity(batch.len());
+        let mut user_ids: Vec<Uuid> = Vec::with_capacity(batch.len());
+        let mut upstream_provider_ids: Vec<Uuid> = Vec::with_capacity(batch.len());
+        let mut subjects: Vec<String> = Vec::with_capacity(batch.len());
+        let mut created_ats: Vec<DateTime<Utc>> = Vec::with_capacity(batch.len());
+
+        for MasNewUpstreamOauthLink {
+            link_id,
+            user_id,
+            upstream_provider_id,
+            subject,
+            created_at,
+        } in batch
+        {
+            link_ids.push(link_id);
+            user_ids.push(user_id.get());
+            upstream_provider_ids.push(upstream_provider_id);
+            subjects.push(subject);
+            created_ats.push(created_at);
+        }
+
+        sqlx::query!(
+            r#"
+            INSERT INTO syn2mas__upstream_oauth_links
+            (upstream_oauth_link_id, user_id, upstream_oauth_provider_id, subject, created_at)
+            SELECT * FROM UNNEST($1::UUID[], $2::UUID[], $3::UUID[], $4::TEXT[], $5::TIMESTAMP WITH TIME ZONE[])
+            "#,
+            &link_ids[..],
+            &user_ids[..],
+            &upstream_provider_ids[..],
+            &subjects[..],
+            &created_ats[..],
+        ).execute(&mut *conn).await.into_database("writing unsupported threepids to MAS")?;
+
+        Ok(())
+    }
+}
+
 pub struct MasNewCompatSession {
     pub session_id: Uuid,
     pub user_id: NonNilUuid,
@@ -890,45 +930,15 @@ impl MasWriter {
         &mut self,
         links: Vec<MasNewUpstreamOauthLink>,
     ) -> BoxFuture<'_, Result<(), Error>> {
-        self.writer_pool.spawn_with_connection(move |conn| {
-            Box::pin(async move {
-                let mut link_ids: Vec<Uuid> = Vec::with_capacity(links.len());
-                let mut user_ids: Vec<Uuid> = Vec::with_capacity(links.len());
-                let mut upstream_provider_ids: Vec<Uuid> = Vec::with_capacity(links.len());
-                let mut subjects: Vec<String> = Vec::with_capacity(links.len());
-                let mut created_ats: Vec<DateTime<Utc>> = Vec::with_capacity(links.len());
+        self.writer_pool
+            .spawn_with_connection(move |conn| {
+                Box::pin(async move {
+                    MasNewUpstreamOauthLink::write_batch(conn, links).await?;
 
-                for MasNewUpstreamOauthLink {
-                    link_id,
-                    user_id,
-                    upstream_provider_id,
-                    subject,
-                    created_at,
-                } in links
-                {
-                    link_ids.push(link_id);
-                    user_ids.push(user_id.get());
-                    upstream_provider_ids.push(upstream_provider_id);
-                    subjects.push(subject);
-                    created_ats.push(created_at);
-                }
-
-                sqlx::query!(
-                    r#"
-                    INSERT INTO syn2mas__upstream_oauth_links
-                    (upstream_oauth_link_id, user_id, upstream_oauth_provider_id, subject, created_at)
-                    SELECT * FROM UNNEST($1::UUID[], $2::UUID[], $3::UUID[], $4::TEXT[], $5::TIMESTAMP WITH TIME ZONE[])
-                    "#,
-                    &link_ids[..],
-                    &user_ids[..],
-                    &upstream_provider_ids[..],
-                    &subjects[..],
-                    &created_ats[..],
-                ).execute(&mut *conn).await.into_database("writing unsupported threepids to MAS")?;
-
-                Ok(())
+                    Ok(())
+                })
             })
-        }).boxed()
+            .boxed()
     }
 
     #[tracing::instrument(skip_all, level = Level::DEBUG)]