Add checks for postgres sequence consistency (#8402)

2 files changed, 6 insertions, 0 deletions

diff --git a/synapse/storage/databases/main/registration.py b/synapse/storage/databases/main/registration.py
index 48ce7ecd16..a83df7759d 100644
--- a/synapse/storage/databases/main/registration.py
+++ b/synapse/storage/databases/main/registration.py
@@ -41,6 +41,9 @@ class RegistrationWorkerStore(SQLBaseStore):
         self.config = hs.config
         self.clock = hs.get_clock()
 
+        # Note: we don't check this sequence for consistency as we'd have to
+        # call `find_max_generated_user_id_localpart` each time, which is
+        # expensive if there are many entries.
         self._user_id_seq = build_sequence_generator(
             database.engine, find_max_generated_user_id_localpart, "user_id_seq",
         )
diff --git a/synapse/storage/databases/state/store.py b/synapse/storage/databases/state/store.py
index bec3780a32..989f0cbc9d 100644
--- a/synapse/storage/databases/state/store.py
+++ b/synapse/storage/databases/state/store.py
@@ -99,6 +99,9 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
         self._state_group_seq_gen = build_sequence_generator(
             self.database_engine, get_max_state_group_txn, "state_group_id_seq"
         )
+        self._state_group_seq_gen.check_consistency(
+            db_conn, table="state_groups", id_column="id"
+        )
 
     @cached(max_entries=10000, iterable=True)
     async def get_state_group_delta(self, state_group):