From 93a84d5e5aee9df869ac9e78a88c294d6311a9ef Mon Sep 17 00:00:00 2001
From: Christian Grothoff <christian@grothoff.org>
Date: Mon, 21 Sep 2015 14:36:18 +0200
Subject: retry transactions on serialization/dead-lock failures (#3990)

---
 src/mintdb/plugin_mintdb_postgres.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

(limited to 'src/mintdb/plugin_mintdb_postgres.c')

diff --git a/src/mintdb/plugin_mintdb_postgres.c b/src/mintdb/plugin_mintdb_postgres.c
index 42aac19f1..621108026 100644
--- a/src/mintdb/plugin_mintdb_postgres.c
+++ b/src/mintdb/plugin_mintdb_postgres.c
@@ -1095,7 +1095,31 @@ postgres_commit (void *cls,
   if (PGRES_COMMAND_OK !=
       PQresultStatus (result))
   {
-    GNUNET_break (0);
+    const char *sqlstate;
+
+    sqlstate = PQresultErrorField (result,
+                                   PG_DIAG_SQLSTATE);
+    if (NULL == sqlstate)
+    {
+      /* very unexpected... */
+      GNUNET_break (0);
+      PQclear (result);
+      return GNUNET_SYSERR;
+    }
+    /* 40P01: deadlock, 40001: serialization failure */
+    if ( (0 == strcmp (sqlstate,
+                       "40P01")) ||
+         (0 == strcmp (sqlstate,
+                       "40001")) )
+    {
+      /* These two can be retried and have a fair chance of working
+         the next time */
+      PQclear (result);
+      return GNUNET_NO;
+    }
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Database commit failure: %s\n",
+                sqlstate);
     PQclear (result);
     return GNUNET_SYSERR;
   }
-- 
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