anastasis

commit 5f65dc323c823e41412d1e802224adf7d18b2441
parent 1f8c8ce04a552a6352cb8074d769a9a70e8fadb2
Author: Christian Grothoff <christian@grothoff.org>
Date:   Fri,  7 Aug 2026 21:06:55 +0200

common commit-after-rollback failure handling fix

Diffstat:
M
src/stasis/anastasis-db_pg.c
 | 
40
+++++++++++++++++++++++++++++++++++++---

1 file changed, 37 insertions(+), 3 deletions(-)
diff --git a/src/stasis/anastasis-db_pg.c b/src/stasis/anastasis-db_pg.c
@@ -90,9 +90,43 @@ ANASTASIS_DB_commit (void)
 
   PREPARE ("do_commit",
            "COMMIT");
-  qs = GNUNET_PQ_eval_prepared_non_select (pg->conn,
-                                           "do_commit",
-                                           no_params);
+  {
+    PGresult *result;
+
+    result = GNUNET_PQ_exec_prepared (pg->conn,
+                                      "do_commit",
+                                      no_params);
+    qs = GNUNET_PQ_eval_result (pg->conn,
+                                "do_commit",
+                                result);
+    /* PostgreSQL accepts COMMIT on a transaction it has already aborted: it
+       silently rolls the transaction back and answers PGRES_COMMAND_OK with the
+       command tag ROLLBACK.  GNUNET_PQ_eval_result() cannot tell that apart from
+       a real commit, so every caller took the success path for a transaction
+       whose writes are gone.  Report it as a soft error instead: sessions run
+       SERIALIZABLE, so the overwhelmingly likely cause is an unhandled
+       40001/40P01 for which retrying is right; a caller with a retry loop gives
+       up after MAX_RETRIES and fails visibly, one without fails immediately.
+
+       The *success* path deliberately keeps returning exactly what
+       GNUNET_PQ_eval_prepared_non_select() returned before.  That function is
+       GNUNET_PQ_exec_prepared() + GNUNET_PQ_eval_result() plus a
+       strtol(PQcmdTuples()) step that only runs when the status is already
+       GNUNET_DB_STATUS_SUCCESS_NO_RESULTS, and PQcmdTuples() on a COMMIT command
+       tag is the empty string -- so that step yields 0, which is
+       GNUNET_DB_STATUS_SUCCESS_NO_RESULTS again. */
+    if ( (0 <= qs) &&
+         (NULL != result) &&
+         (0 == strcmp ("ROLLBACK",
+                       PQcmdStatus (result))) )
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                  "Transaction `%s' was rolled back by the database instead of committed; a previous statement must have failed without being handled\n",
+                  pg->transaction_name);
+      qs = GNUNET_DB_STATUS_SOFT_ERROR;
+    }
+    PQclear (result);
+  }
   pg->transaction_name = NULL;
   return qs;
 }