pgq.maint_rotate_tables: check txid sanity, fail if bad

1 files changed, 6 insertions, 0 deletions

diff --git a/sql/pgq/functions/pgq.maint_rotate_tables.sql b/sql/pgq/functions/pgq.maint_rotate_tables.sql
index d972a04e..d3cee739 100644
--- a/sql/pgq/functions/pgq.maint_rotate_tables.sql
+++ b/sql/pgq/functions/pgq.maint_rotate_tables.sql
@@ -30,6 +30,12 @@ begin
         return 0;
     end if;
 
+    -- if DB is in invalid state, stop
+    if txid_current() < cf.queue_switch_step1 then
+        raise exception 'queue % maint failure: step1=%, current=%',
+                i_queue_name, cf.queue_switch_step1, txid_current();
+    end if;
+
     -- find lowest tick for that queue
     select min(sub_last_tick) into lowest_tick_id
       from pgq.subscription