diff --git a/src/benchmark/exchange_benchmark_home/.config/taler/account-2.json b/src/benchmark/exchange_benchmark_home/.config/taler/account-2.json
index 5e8dc44e9..35a5ec319 100644
--- a/src/benchmark/exchange_benchmark_home/.config/taler/account-2.json
+++ b/src/benchmark/exchange_benchmark_home/.config/taler/account-2.json
@@ -1,5 +1,5 @@
 {
   "url": "payto://x-taler-bank/localhost:8082/2",
-  "salt": "KY6F590HGDDJ2W8X1PFFKQDV5WNR6EFTBY2Q7MXCG4FQFZ53RKS2DA0DMQAK20V9B6P4JHB55E41XT905YEQHB0S9PA2YCDS2VSV6QR",
-  "master_sig": "W2GC7FF6NG8D6NGT1XKYF2GDDA2W2Q4GH1AZ47KD3MY4CNS29QF4VH1DWE11NW33ZPTCV4XMMGNSE1KKFF7DMK81R8A2VBBF8FMFY0R"
+  "salt": "1D8FXNTNHJZH0FQ60CT136GTHCMBM3WBDMGWNBFXMQ2R7XSCY69Y5MG1745WBJZAWWPNRCXD7KV8CCRWYZ10Y6D1694RVSGBFZFND2R",
+  "master_sig": "CRYKJBSH7QJ9Q32SPSR2PQNMFNSV76Q6JN4GHNQXYZ14CC4SFWYM9XWK678XZ05T6QYV0PD76Q4S1E5V7SJ7A49GQW6CZJS8YWH6W28"
 }
\ No newline at end of file
diff --git a/src/benchmark/taler-exchange-benchmark.c b/src/benchmark/taler-exchange-benchmark.c
index 3440b3b4e..3a59bc6c9 100644
--- a/src/benchmark/taler-exchange-benchmark.c
+++ b/src/benchmark/taler-exchange-benchmark.c
@@ -22,6 +22,7 @@
  * @brief HTTP serving layer intended to perform crypto-work and
  * communication with the exchange
  * @author Marcello Stanisci
+ * @author Christian Grothoff
  */
 
 #include "platform.h"
diff --git a/src/exchange/taler-exchange-httpd_db.c b/src/exchange/taler-exchange-httpd_db.c
index 7817de990..1f7e0f257 100644
--- a/src/exchange/taler-exchange-httpd_db.c
+++ b/src/exchange/taler-exchange-httpd_db.c
@@ -30,7 +30,7 @@
  * How often should we retry a transaction before giving up
  * (for transactions resulting in serialization/dead locks only).
  */
-#define MAX_TRANSACTION_COMMIT_RETRIES 3
+#define MAX_TRANSACTION_COMMIT_RETRIES 2
 
 
 /**
@@ -108,8 +108,9 @@ TEH_DB_run_transaction (struct MHD_Connection *connection,
     if (0 <= qs)
       return GNUNET_OK;
   }
-  TALER_LOG_WARNING ("Transaction commit failed %u times\n",
-		     MAX_TRANSACTION_COMMIT_RETRIES);
+  TALER_LOG_ERROR ("Transaction `%s' commit failed %u times\n",
+                   name,
+                   MAX_TRANSACTION_COMMIT_RETRIES);
   if (NULL != mhd_ret)
     *mhd_ret = TEH_RESPONSE_reply_commit_error (connection,
 						TALER_EC_DB_COMMIT_FAILED_ON_RETRY);
diff --git a/src/exchangedb/plugin_exchangedb_postgres.c b/src/exchangedb/plugin_exchangedb_postgres.c
index b9c577bcc..ac8d395c6 100644
--- a/src/exchangedb/plugin_exchangedb_postgres.c
+++ b/src/exchangedb/plugin_exchangedb_postgres.c
@@ -573,7 +573,8 @@ postgres_prepare (PGconn *db_conn)
                             ",expiration_date"
                             " FROM reserves"
                             " WHERE reserve_pub=$1"
-                            " LIMIT 1;",
+                            " LIMIT 1"
+                            " FOR UPDATE;",
                             1),
     /* Used in #postgres_reserves_in_insert() when the reserve is new */
     GNUNET_PQ_make_prepare ("reserve_create",
@@ -782,7 +783,8 @@ postgres_prepare (PGconn *db_conn)
                             " FROM known_coins"
                             "    JOIN denominations denom"
                             "      USING (denom_pub_hash)"
-                            " WHERE coin_pub=$1;",
+                            " WHERE coin_pub=$1"
+                            " FOR UPDATE;",
                             1),
     /* Used in #postgres_insert_known_coin() to store
        the denomination public key and signature for
@@ -895,7 +897,8 @@ postgres_prepare (PGconn *db_conn)
                             "    JOIN denominations denom "
                             "      USING (denom_pub_hash)"
                             " WHERE rc=$1"
-                            "   ORDER BY newcoin_index ASC;",
+                            "   ORDER BY newcoin_index ASC"
+                            " FOR UPDATE;",
                             1),
 
     /* Used in #postgres_insert_refresh_reveal() to store the transfer
@@ -1008,7 +1011,8 @@ postgres_prepare (PGconn *db_conn)
                             "        (coin_pub=$1)"
                             "    AND (h_contract_terms=$2)"
                             "    AND (merchant_pub=$3)"
-                            " );",
+                            " )"
+                            " FOR UPDATE;",
                             3),
     /* Fetch deposits with rowid '\geq' the given parameter */
     GNUNET_PQ_make_prepare ("audit_get_deposits_incr",
@@ -1150,7 +1154,8 @@ postgres_prepare (PGconn *db_conn)
                             "      USING (coin_pub)"
                             "    JOIN denominations denom"
                             "      USING (denom_pub_hash)"
-                            " WHERE coin_pub=$1;",
+                            " WHERE coin_pub=$1"
+                            " FOR UPDATE;",
                             1),
 
     /* Used in #postgres_get_link_data(). */
@@ -1564,7 +1569,8 @@ postgres_prepare (PGconn *db_conn)
                             " reserve_pub"
                             " FROM reserves_out"
                             " WHERE h_blind_ev=$1"
-                            " LIMIT 1;",
+                            " LIMIT 1"
+                            " FOR UPDATE;",
                             1),
     /* used in #postgres_commit */
     GNUNET_PQ_make_prepare ("do_commit",