Allow configuring synapse database transaction limit

roles/matrix-synapse/defaults/main.yml

@@ -453,6 +453,7 @@ matrix_synapse_replication_http_port: 9093
 matrix_synapse_sentry_dsn: ""
 
 # Postgres database information
+matrix_synapse_database_txn_limit: 0
 matrix_synapse_database_host: "matrix-postgres"
 matrix_synapse_database_port: 5432
 matrix_synapse_database_user: "synapse"

roles/matrix-synapse/templates/synapse/homeserver.yaml.j2

@@ -777,6 +777,7 @@ caches:
 database:
   # The database engine name
   name: "psycopg2"
+  txn_limit: {{ matrix_synapse_database_txn_limit }}
   args:
     user: {{ matrix_synapse_database_user|string|to_json }}
     password: {{ matrix_synapse_database_password|string|to_json }}