sql: Include system indexes in read transactions

src/adapter/src/coord/introspection.rs

@@ -144,6 +144,11 @@ pub fn auto_run_on_introspection<'a, 's, 'p>(
         return TargetCluster::Active;
     }
 
+    // Auto-routing mid transaction can cause an abort due to an invalid timedomain.
+    if session.transaction().is_in_multi_statement_transaction() {
+        return TargetCluster::Active;
+    }
+
     // These dependencies are just existing dataflows that are referenced in the plan.
     let mut depends_on = depends_on.into_iter().peekable();
     let has_dependencies = depends_on.peek().is_some();

test/sqllogictest/timedomain.slt

@@ -66,7 +66,8 @@ SELECT * FROM t;
 statement ok
 ROLLBACK
 
-# Test that user table and system tables can be mixed in a transaction.
+# Test that user table and mz_catalog system tables cannot be mixed in a transaction because they
+# belong to different timedomains.
 
 statement ok
 BEGIN;
@@ -75,11 +76,13 @@ query I rowsort
 SELECT * FROM t
 ----
 
-statement ok
-SELECT * FROM mz_views
+# This may stop failing in the future if a view in pg_catalog starts to depend on this. In that case
+# just change this query to select from an object that isn't referenced from pg_catalog.
+query error Transactions can only reference objects in the same timedomain.
+SELECT * FROM mz_internal.mz_show_default_privileges
 
 statement ok
-COMMIT
+ROLLBACK
 
 # Test that timeline dependent queries can be included in transaction.