From 6503a9fe359f07ca4da9e6ab1c3b64b39b4fa24d Mon Sep 17 00:00:00 2001
From: Christian Grothoff <christian@grothoff.org>
Date: Mon, 10 Aug 2020 08:12:01 +0200
Subject: experimental fix to #6452: merge two SQL statements into one

---
 src/exchangedb/plugin_exchangedb_postgres.c | 51 ++++++++++++++++++++++++++++-
 1 file changed, 50 insertions(+), 1 deletion(-)

(limited to 'src')

diff --git a/src/exchangedb/plugin_exchangedb_postgres.c b/src/exchangedb/plugin_exchangedb_postgres.c
index 1cb10ea84..1dc58883d 100644
--- a/src/exchangedb/plugin_exchangedb_postgres.c
+++ b/src/exchangedb/plugin_exchangedb_postgres.c
@@ -399,6 +399,30 @@ postgres_get_session (void *cls)
                               " WHERE"
                               " reserve_pub=$5;",
                               5),
+      /* Used in #insert_withdraw_info() when coins are withdrawn from the reserve */
+      GNUNET_PQ_make_prepare ("reserve_reduce",
+                              "UPDATE reserves"
+                              " SET"
+                              " gc_date="
+                              " CASE WHEN (reserves.gc_date > $2)"
+                              "      THEN reserves.gc_date"
+                              "      ELSE $2"
+                              " END"
+                              ",current_balance_val="
+                              " CASE WHEN (reserves.current_balance_frac >= $4)"
+                              "      THEN reserves.current_balance_val - $3"
+                              "      ELSE reserves.current_balance_val - $3 - 1"
+                              " END"
+                              ",current_balance_frac="
+                              " CASE WHEN (reserves.current_balance_frac >= $4)"
+                              "      THEN reserves.current_balance_frac - $4"
+                              "      ELSE 100000000 + reserves.current_balance_frac - $4"
+                              " END"
+                              " WHERE reserve_pub=$1"
+                              "  AND current_balance_val >= $3"
+                              "  AND ( (current_balance_frac >= $4) OR"
+                              "        (current_balance_val > $3) )",
+                              4),
       /* Used in #postgres_reserves_in_insert() to store transaction details */
       GNUNET_PQ_make_prepare ("reserves_in_add_transaction",
                               "INSERT INTO reserves_in "
@@ -2154,6 +2178,7 @@ postgres_insert_withdraw_info (
     return qs;
   }
 
+#if 0
   /* update reserve balance */
   reserve.pub = collectable->reserve_pub;
   if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT !=
@@ -2178,7 +2203,7 @@ postgres_insert_withdraw_info (
     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                 "Withdrawal from reserve `%s' refused due to balance mismatch. Retrying.\n",
                 TALER_B2S (&collectable->reserve_pub));
-    return GNUNET_DB_STATUS_SOFT_ERROR;
+    return GNUNET_DB_STATUS_SOFT_ERROR; // FIXME: really soft error? would retry help!?
   }
   expiry = GNUNET_TIME_absolute_add (now,
                                      pg->legal_reserve_expiration_time);
@@ -2194,6 +2219,30 @@ postgres_insert_withdraw_info (
     GNUNET_break (0);
     qs = GNUNET_DB_STATUS_HARD_ERROR;
   }
+#else
+  {
+    struct GNUNET_PQ_QueryParam params[] = {
+      GNUNET_PQ_query_param_auto_from_type (&collectable->reserve_pub),
+      TALER_PQ_query_param_absolute_time (&expiry),
+      TALER_PQ_query_param_amount (&collectable->amount_with_fee),
+      GNUNET_PQ_query_param_end
+    };
+
+    expiry = GNUNET_TIME_absolute_add (now,
+                                       pg->legal_reserve_expiration_time);
+    qs = GNUNET_PQ_eval_prepared_non_select (session->conn,
+                                             "reserve_reduce",
+                                             params);
+    if (0 == qs)
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  "Withdrawal from reserve `%s' refused due to balance mismatch.\n",
+                  TALER_B2S (&collectable->reserve_pub));
+      return GNUNET_DB_STATUS_HARD_ERROR;
+    }
+  }
+
+#endif
   return qs;
 }
 
-- 
cgit v1.2.3