1 files changed, 17 insertions, 5 deletions
diff --git a/syncapi/storage/postgres/memberships_table.go b/syncapi/storage/postgres/memberships_table.go
index ac44b235..47833893 100644
--- a/syncapi/storage/postgres/memberships_table.go
+++ b/syncapi/storage/postgres/memberships_table.go
@@ -65,18 +65,22 @@ const selectMembershipCountSQL = "" +
 const selectMembershipBeforeSQL = "" +
 	"SELECT membership, topological_pos FROM syncapi_memberships WHERE room_id = $1 and user_id = $2 AND topological_pos <= $3 ORDER BY topological_pos DESC LIMIT 1"
 
+const purgeMembershipsSQL = "" +
+	"DELETE FROM syncapi_memberships WHERE room_id = $1"
+
 const selectMembersSQL = `
-SELECT event_id FROM (
-	SELECT DISTINCT ON (room_id, user_id) room_id, user_id, event_id, membership FROM syncapi_memberships WHERE room_id = $1 AND topological_pos <= $2 ORDER BY room_id, user_id, stream_pos DESC  
-) t 
-WHERE ($3::text IS NULL OR t.membership = $3)
-	AND ($4::text IS NULL OR t.membership <> $4)
+	SELECT event_id FROM (
+		SELECT DISTINCT ON (room_id, user_id) room_id, user_id, event_id, membership FROM syncapi_memberships WHERE room_id = $1 AND topological_pos <= $2 ORDER BY room_id, user_id, stream_pos DESC  
+	) t 
+	WHERE ($3::text IS NULL OR t.membership = $3)
+		AND ($4::text IS NULL OR t.membership <> $4)
 `
 
 type membershipsStatements struct {
 	upsertMembershipStmt        *sql.Stmt
 	selectMembershipCountStmt   *sql.Stmt
 	selectMembershipForUserStmt *sql.Stmt
+	purgeMembershipsStmt        *sql.Stmt
 	selectMembersStmt           *sql.Stmt
 }
 
@@ -90,6 +94,7 @@ func NewPostgresMembershipsTable(db *sql.DB) (tables.Memberships, error) {
 		{&s.upsertMembershipStmt, upsertMembershipSQL},
 		{&s.selectMembershipCountStmt, selectMembershipCountSQL},
 		{&s.selectMembershipForUserStmt, selectMembershipBeforeSQL},
+		{&s.purgeMembershipsStmt, purgeMembershipsSQL},
 		{&s.selectMembersStmt, selectMembersSQL},
 	}.Prepare(db)
 }
@@ -139,6 +144,13 @@ func (s *membershipsStatements) SelectMembershipForUser(
 	return membership, topologyPos, nil
 }
 
+func (s *membershipsStatements) PurgeMemberships(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.purgeMembershipsStmt).ExecContext(ctx, roomID)
+	return err
+}
+
 func (s *membershipsStatements) SelectMemberships(
 	ctx context.Context, txn *sql.Tx,
 	roomID string, pos types.TopologyToken,