Factor out {lookup,delete,insert,update,lock}_product(s) (shit job)

14 files changed, 829 insertions, 459 deletions

diff --git a/src/backenddb/Makefile.am b/src/backenddb/Makefile.am
index 6227eba2..91b48223 100644
--- a/src/backenddb/Makefile.am
+++ b/src/backenddb/Makefile.am
@@ -75,6 +75,12 @@ libtaler_plugin_merchantdb_postgres_la_SOURCES = \
   pg_update_instance_auth.h pg_update_instance_auth.c \
   pg_inactivate_account.h pg_inactivate_account.c \
   pg_activate_account.h pg_activate_account.c \
+  pg_lookup_products.h pg_lookup_products.c \
+  pg_lookup_product.h pg_lookup_product.c \
+  pg_delete_product.h pg_delete_product.c \
+  pg_insert_product.h pg_insert_product.c \
+  pg_update_product.h pg_update_product.c \
+  pg_lock_product.h pg_lock_product.c \
   plugin_merchantdb_postgres.c  pg_helper.h
 libtaler_plugin_merchantdb_postgres_la_LIBADD = \
   $(LTLIBINTL)
diff --git a/src/backenddb/pg_delete_product.c b/src/backenddb/pg_delete_product.c
new file mode 100644
index 00000000..2d70c9b8
--- /dev/null
+++ b/src/backenddb/pg_delete_product.c
@@ -0,0 +1,57 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2022 Taler Systems SA
+
+   TALER is free software; you can redistribute it and/or modify it under the
+   terms of the GNU General Public License as published by the Free Software
+   Foundation; either version 3, or (at your option) any later version.
+
+   TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along with
+   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+/**
+ * @file backenddb/pg_delete_product.c
+ * @brief Implementation of the delete_product function for Postgres
+ * @author Iván Ávalos
+ */
+#include "platform.h"
+#include <taler/taler_error_codes.h>
+#include <taler/taler_dbevents.h>
+#include <taler/taler_pq_lib.h>
+#include "pg_delete_product.h"
+#include "pg_helper.h"
+
+enum GNUNET_DB_QueryStatus
+TMH_PG_delete_product (void *cls,
+                       const char *instance_id,
+                       const char *product_id)
+{
+  struct PostgresClosure *pg = cls;
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_string (instance_id),
+    GNUNET_PQ_query_param_string (product_id),
+    GNUNET_PQ_query_param_end
+  };
+
+  check_connection (pg);
+  PREPARE (pg,
+           "delete_product",
+           "DELETE"
+           " FROM merchant_inventory"
+           " WHERE merchant_inventory.merchant_serial="
+           "     (SELECT merchant_serial "
+           "        FROM merchant_instances"
+           "        WHERE merchant_id=$1)"
+           "   AND merchant_inventory.product_id=$2"
+           "   AND product_serial NOT IN "
+           "     (SELECT product_serial FROM merchant_order_locks)"
+           "   AND product_serial NOT IN "
+           "     (SELECT product_serial FROM merchant_inventory_locks)");
+  return GNUNET_PQ_eval_prepared_non_select (pg->conn,
+                                             "delete_product",
+                                             params);
+}
diff --git a/src/backenddb/pg_delete_product.h b/src/backenddb/pg_delete_product.h
new file mode 100644
index 00000000..c88e46f4
--- /dev/null
+++ b/src/backenddb/pg_delete_product.h
@@ -0,0 +1,43 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2022 Taler Systems SA
+
+   TALER is free software; you can redistribute it and/or modify it under the
+   terms of the GNU General Public License as published by the Free Software
+   Foundation; either version 3, or (at your option) any later version.
+
+   TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along with
+   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+/**
+ * @file backenddb/pg_delete_product.h
+ * @brief implementation of the delete_product function for Postgres
+ * @author Iván Ávalos
+ */
+#ifndef PG_DELETE_PRODUCT_H
+#define PG_DELETE_PRODUCT_H
+
+#include <taler/taler_util.h>
+#include <taler/taler_json_lib.h>
+#include "taler_merchantdb_plugin.h"
+
+/**
+ * Delete information about a product.  Note that the transaction must
+ * enforce that no stocks are currently locked.
+ *
+ * @param cls closure
+ * @param instance_id instance to delete product of
+ * @param product_id product to delete
+ * @return DB status code, #GNUNET_DB_STATUS_SUCCESS_NO_RESULTS
+ *           if locks prevent deletion OR product unknown
+ */
+enum GNUNET_DB_QueryStatus
+TMH_PG_delete_product (void *cls,
+                       const char *instance_id,
+                       const char *product_id);
+
+#endif
diff --git a/src/backenddb/pg_insert_product.c b/src/backenddb/pg_insert_product.c
new file mode 100644
index 00000000..8ee2b274
--- /dev/null
+++ b/src/backenddb/pg_insert_product.c
@@ -0,0 +1,76 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2022 Taler Systems SA
+
+   TALER is free software; you can redistribute it and/or modify it under the
+   terms of the GNU General Public License as published by the Free Software
+   Foundation; either version 3, or (at your option) any later version.
+
+   TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along with
+   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+/**
+ * @file backenddb/pg_insert_product.c
+ * @brief Implementation of the insert_product function for Postgres
+ * @author Iván Ávalos
+ */
+#include "platform.h"
+#include <taler/taler_error_codes.h>
+#include <taler/taler_dbevents.h>
+#include <taler/taler_pq_lib.h>
+#include "pg_insert_product.h"
+#include "pg_helper.h"
+
+enum GNUNET_DB_QueryStatus
+TMH_PG_insert_product (void *cls,
+                       const char *instance_id,
+                       const char *product_id,
+                       const struct TALER_MERCHANTDB_ProductDetails *pd)
+{
+  struct PostgresClosure *pg = cls;
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_string (instance_id),
+    GNUNET_PQ_query_param_string (product_id),
+    GNUNET_PQ_query_param_string (pd->description),
+    TALER_PQ_query_param_json (pd->description_i18n),
+    GNUNET_PQ_query_param_string (pd->unit),
+    GNUNET_PQ_query_param_string (pd->image),
+    TALER_PQ_query_param_json (pd->taxes),
+    TALER_PQ_query_param_amount (&pd->price),
+    GNUNET_PQ_query_param_uint64 (&pd->total_stock),
+    TALER_PQ_query_param_json (pd->address),
+    GNUNET_PQ_query_param_timestamp (&pd->next_restock),
+    GNUNET_PQ_query_param_uint32 (&pd->minimum_age),
+    GNUNET_PQ_query_param_end
+  };
+
+  check_connection (pg);
+  PREPARE (pg,
+           "insert_product",
+           "INSERT INTO merchant_inventory"
+           "(merchant_serial"
+           ",product_id"
+           ",description"
+           ",description_i18n"
+           ",unit"
+           ",image"
+           ",taxes"
+           ",price_val"
+           ",price_frac"
+           ",total_stock"
+           ",address"
+           ",next_restock"
+           ",minimum_age"
+           ")"
+           " SELECT merchant_serial,"
+           " $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13"
+           " FROM merchant_instances"
+           " WHERE merchant_id=$1");
+  return GNUNET_PQ_eval_prepared_non_select (pg->conn,
+                                             "insert_product",
+                                             params);
+}
diff --git a/src/backenddb/pg_insert_product.h b/src/backenddb/pg_insert_product.h
new file mode 100644
index 00000000..169bd150
--- /dev/null
+++ b/src/backenddb/pg_insert_product.h
@@ -0,0 +1,43 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2022 Taler Systems SA
+
+   TALER is free software; you can redistribute it and/or modify it under the
+   terms of the GNU General Public License as published by the Free Software
+   Foundation; either version 3, or (at your option) any later version.
+
+   TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along with
+   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+/**
+ * @file backenddb/pg_insert_product.h
+ * @brief implementation of the insert_product function for Postgres
+ * @author Iván Ávalos
+ */
+#ifndef PG_INSERT_PRODUCT_H
+#define PG_INSERT_PRODUCT_H
+
+#include <taler/taler_util.h>
+#include <taler/taler_json_lib.h>
+#include "taler_merchantdb_plugin.h"
+
+/**
+ * Insert details about a particular product.
+ *
+ * @param cls closure
+ * @param instance_id instance to insert product for
+ * @param product_id product identifier of product to insert
+ * @param pd the product details to insert
+ * @return database result code
+ */
+enum GNUNET_DB_QueryStatus
+TMH_PG_insert_product (void *cls,
+                       const char *instance_id,
+                       const char *product_id,
+                       const struct TALER_MERCHANTDB_ProductDetails *pd);
+
+#endif
diff --git a/src/backenddb/pg_lock_product.c b/src/backenddb/pg_lock_product.c
new file mode 100644
index 00000000..205f0b67
--- /dev/null
+++ b/src/backenddb/pg_lock_product.c
@@ -0,0 +1,76 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2022 Taler Systems SA
+
+   TALER is free software; you can redistribute it and/or modify it under the
+   terms of the GNU General Public License as published by the Free Software
+   Foundation; either version 3, or (at your option) any later version.
+
+   TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along with
+   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+/**
+ * @file backenddb/pg_lock_product.c
+ * @brief Implementation of the lock_product function for Postgres
+ * @author Iván Ávalos
+ */
+#include "platform.h"
+#include <taler/taler_error_codes.h>
+#include <taler/taler_dbevents.h>
+#include <taler/taler_pq_lib.h>
+#include "pg_lock_product.h"
+#include "pg_helper.h"
+
+enum GNUNET_DB_QueryStatus
+TMH_PG_lock_product (void *cls,
+                     const char *instance_id,
+                     const char *product_id,
+                     const struct GNUNET_Uuid *uuid,
+                     uint64_t quantity,
+                     struct GNUNET_TIME_Timestamp expiration_time)
+{
+  struct PostgresClosure *pg = cls;
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_string (instance_id),
+    GNUNET_PQ_query_param_string (product_id),
+    GNUNET_PQ_query_param_auto_from_type (uuid),
+    GNUNET_PQ_query_param_uint64 (&quantity),
+    GNUNET_PQ_query_param_timestamp (&expiration_time),
+    GNUNET_PQ_query_param_end
+  };
+
+  check_connection (pg);
+  PREPARE (pg,
+           "lock_product",
+           "WITH ps AS"
+           "  (SELECT product_serial"
+           "   FROM merchant_inventory"
+           "   WHERE product_id=$2"
+           "     AND merchant_serial="
+           "     (SELECT merchant_serial"
+           "        FROM merchant_instances"
+           "        WHERE merchant_id=$1))"
+           "INSERT INTO merchant_inventory_locks"
+           "(product_serial"
+           ",lock_uuid"
+           ",total_locked"
+           ",expiration)"
+           " SELECT product_serial, $3, $4, $5"
+           "   FROM merchant_inventory"
+           "   JOIN ps USING (product_serial)"
+           "   WHERE "
+           "     total_stock - total_sold - total_lost - $4 >= "
+           "     (SELECT COALESCE(SUM(total_locked), 0)"
+           "        FROM merchant_inventory_locks"
+           "        WHERE product_serial=ps.product_serial) + "
+           "     (SELECT COALESCE(SUM(total_locked), 0)"
+           "        FROM merchant_order_locks"
+           "        WHERE product_serial=ps.product_serial)");
+  return GNUNET_PQ_eval_prepared_non_select (pg->conn,
+                                             "lock_product",
+                                             params);
+}
diff --git a/src/backenddb/pg_lock_product.h b/src/backenddb/pg_lock_product.h
new file mode 100644
index 00000000..d0e13d41
--- /dev/null
+++ b/src/backenddb/pg_lock_product.h
@@ -0,0 +1,49 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2022 Taler Systems SA
+
+   TALER is free software; you can redistribute it and/or modify it under the
+   terms of the GNU General Public License as published by the Free Software
+   Foundation; either version 3, or (at your option) any later version.
+
+   TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along with
+   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+/**
+ * @file backenddb/pg_lock_product.h
+ * @brief implementation of the lock_product function for Postgres
+ * @author Iván Ávalos
+ */
+#ifndef PG_LOCK_PRODUCT_H
+#define PG_LOCK_PRODUCT_H
+
+#include <taler/taler_util.h>
+#include <taler/taler_json_lib.h>
+#include "taler_merchantdb_plugin.h"
+
+/**
+ * Lock stocks of a particular product. Note that the transaction must
+ * enforce that the "stocked-sold-lost >= locked" constraint holds.
+ *
+ * @param cls closure
+ * @param instance_id instance to lookup products for
+ * @param product_id product to lookup
+ * @param uuid the UUID that holds the lock
+ * @param quantity how many units should be locked
+ * @param expiration_time when should the lock expire
+ * @return database result code, #GNUNET_DB_STATUS_SUCCESS_NO_RESULTS if the
+ *         product is unknown OR if there insufficient stocks remaining
+ */
+enum GNUNET_DB_QueryStatus
+TMH_PG_lock_product (void *cls,
+                     const char *instance_id,
+                     const char *product_id,
+                     const struct GNUNET_Uuid *uuid,
+                     uint64_t quantity,
+                     struct GNUNET_TIME_Timestamp expiration_time);
+
+#endif
diff --git a/src/backenddb/pg_lookup_product.c b/src/backenddb/pg_lookup_product.c
new file mode 100644
index 00000000..d9eb0915
--- /dev/null
+++ b/src/backenddb/pg_lookup_product.c
@@ -0,0 +1,110 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2022 Taler Systems SA
+
+   TALER is free software; you can redistribute it and/or modify it under the
+   terms of the GNU General Public License as published by the Free Software
+   Foundation; either version 3, or (at your option) any later version.
+
+   TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along with
+   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+/**
+ * @file backenddb/pg_lookup_product.c
+ * @brief Implementation of the lookup_product function for Postgres
+ * @author Iván Ávalos
+ */
+#include "platform.h"
+#include <taler/taler_error_codes.h>
+#include <taler/taler_dbevents.h>
+#include <taler/taler_pq_lib.h>
+#include "pg_lookup_product.h"
+#include "pg_helper.h"
+
+enum GNUNET_DB_QueryStatus
+TMH_PG_lookup_product (void *cls,
+                       const char *instance_id,
+                       const char *product_id,
+                       struct TALER_MERCHANTDB_ProductDetails *pd)
+{
+  struct PostgresClosure *pg = cls;
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_string (instance_id),
+    GNUNET_PQ_query_param_string (product_id),
+    GNUNET_PQ_query_param_end
+  };
+
+  if (NULL == pd)
+  {
+    struct GNUNET_PQ_ResultSpec rs_null[] = {
+      GNUNET_PQ_result_spec_end
+    };
+
+    check_connection (pg);
+    return GNUNET_PQ_eval_prepared_singleton_select (pg->conn,
+                                                     "lookup_product",
+                                                     params,
+                                                     rs_null);
+  }
+  else
+  {
+    struct GNUNET_PQ_ResultSpec rs[] = {
+      GNUNET_PQ_result_spec_string ("description",
+                                    &pd->description),
+      TALER_PQ_result_spec_json ("description_i18n",
+                                 &pd->description_i18n),
+      GNUNET_PQ_result_spec_string ("unit",
+                                    &pd->unit),
+      TALER_PQ_RESULT_SPEC_AMOUNT ("price",
+                                   &pd->price),
+      TALER_PQ_result_spec_json ("taxes",
+                                 &pd->taxes),
+      GNUNET_PQ_result_spec_uint64 ("total_stock",
+                                    &pd->total_stock),
+      GNUNET_PQ_result_spec_uint64 ("total_sold",
+                                    &pd->total_sold),
+      GNUNET_PQ_result_spec_uint64 ("total_lost",
+                                    &pd->total_lost),
+      GNUNET_PQ_result_spec_string ("image",
+                                    &pd->image),
+      TALER_PQ_result_spec_json ("address",
+                                 &pd->address),
+      GNUNET_PQ_result_spec_timestamp ("next_restock",
+                                       &pd->next_restock),
+      GNUNET_PQ_result_spec_uint32 ("minimum_age",
+                                    &pd->minimum_age),
+      GNUNET_PQ_result_spec_end
+    };
+
+    check_connection (pg);
+    PREPARE (pg,
+             "lookup_product",
+             "SELECT"
+             " description"
+             ",description_i18n"
+             ",unit"
+             ",price_val"
+             ",price_frac"
+             ",taxes"
+             ",total_stock"
+             ",total_sold"
+             ",total_lost"
+             ",image"
+             ",merchant_inventory.address"
+             ",next_restock"
+             ",minimum_age"
+             " FROM merchant_inventory"
+             " JOIN merchant_instances"
+             "   USING (merchant_serial)"
+             " WHERE merchant_instances.merchant_id=$1"
+             "   AND merchant_inventory.product_id=$2");
+    return GNUNET_PQ_eval_prepared_singleton_select (pg->conn,
+                                                     "lookup_product",
+                                                     params,
+                                                     rs);
+  }
+}
diff --git a/src/backenddb/pg_lookup_product.h b/src/backenddb/pg_lookup_product.h
new file mode 100644
index 00000000..a6add4cb
--- /dev/null
+++ b/src/backenddb/pg_lookup_product.h
@@ -0,0 +1,44 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2022 Taler Systems SA
+
+   TALER is free software; you can redistribute it and/or modify it under the
+   terms of the GNU General Public License as published by the Free Software
+   Foundation; either version 3, or (at your option) any later version.
+
+   TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along with
+   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+/**
+ * @file backenddb/pg_lookup_product.h
+ * @brief implementation of the lookup_product function for Postgres
+ * @author Iván Ávalos
+ */
+#ifndef PG_LOOKUP_PRODUCT_H
+#define PG_LOOKUP_PRODUCT_H
+
+#include <taler/taler_util.h>
+#include <taler/taler_json_lib.h>
+#include "taler_merchantdb_plugin.h"
+
+/**
+ * Lookup details about a particular product.
+ *
+ * @param cls closure
+ * @param instance_id instance to lookup products for
+ * @param product_id product to lookup
+ * @param[out] pd set to the product details on success, can be NULL
+ *             (in that case we only want to check if the product exists)
+ * @return database result code
+ */
+enum GNUNET_DB_QueryStatus
+TMH_PG_lookup_product (void *cls,
+                       const char *instance_id,
+                       const char *product_id,
+                       struct TALER_MERCHANTDB_ProductDetails *pd);
+
+#endif
diff --git a/src/backenddb/pg_lookup_products.c b/src/backenddb/pg_lookup_products.c
new file mode 100644
index 00000000..c04ad5f2
--- /dev/null
+++ b/src/backenddb/pg_lookup_products.c
@@ -0,0 +1,126 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2022 Taler Systems SA
+
+   TALER is free software; you can redistribute it and/or modify it under the
+   terms of the GNU General Public License as published by the Free Software
+   Foundation; either version 3, or (at your option) any later version.
+
+   TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along with
+   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+/**
+ * @file backenddb/pg_lookup_products.c
+ * @brief Implementation of the lookup_products function for Postgres
+ * @author Iván Ávalos
+ */
+#include "platform.h"
+#include <taler/taler_error_codes.h>
+#include <taler/taler_dbevents.h>
+#include <taler/taler_pq_lib.h>
+#include "pg_lookup_products.h"
+#include "pg_helper.h"
+
+/**
+ * Context used for postgres_lookup_products().
+ */
+struct LookupProductsContext
+{
+  /**
+   * Function to call with the results.
+   */
+  TALER_MERCHANTDB_ProductsCallback cb;
+
+  /**
+   * Closure for @a cb.
+   */
+  void *cb_cls;
+
+  /**
+   * Did database result extraction fail?
+   */
+  bool extract_failed;
+};
+
+
+/**
+ * Function to be called with the results of a SELECT statement
+ * that has returned @a num_results results about products.
+ *
+ * @param[in,out] cls of type `struct LookupProductsContext *`
+ * @param result the postgres result
+ * @param num_results the number of results in @a result
+ */
+static void
+lookup_products_cb (void *cls,
+                    PGresult *result,
+                    unsigned int num_results)
+{
+  struct LookupProductsContext *plc = cls;
+
+  for (unsigned int i = 0; i < num_results; i++)
+  {
+    char *product_id;
+    struct GNUNET_PQ_ResultSpec rs[] = {
+      GNUNET_PQ_result_spec_string ("product_id",
+                                    &product_id),
+      GNUNET_PQ_result_spec_end
+    };
+
+    if (GNUNET_OK !=
+        GNUNET_PQ_extract_result (result,
+                                  rs,
+                                  i))
+    {
+      GNUNET_break (0);
+      plc->extract_failed = true;
+      return;
+    }
+    plc->cb (plc->cb_cls,
+             product_id);
+    GNUNET_PQ_cleanup_result (rs);
+  }
+}
+
+enum GNUNET_DB_QueryStatus
+TMH_PG_lookup_products (void *cls,
+                        const char *instance_id,
+                        TALER_MERCHANTDB_ProductsCallback cb,
+                        void *cb_cls)
+{
+  struct PostgresClosure *pg = cls;
+  struct LookupProductsContext plc = {
+    .cb = cb,
+    .cb_cls = cb_cls,
+    /* Can be overwritten by the lookup_products_cb */
+    .extract_failed = false,
+  };
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_string (instance_id),
+    GNUNET_PQ_query_param_end
+  };
+  enum GNUNET_DB_QueryStatus qs;
+
+  check_connection (pg);
+  PREPARE (pg,
+           "lookup_products",
+           "SELECT"
+           " product_id"
+           " FROM merchant_inventory"
+           " JOIN merchant_instances"
+           "   USING (merchant_serial)"
+           " WHERE merchant_instances.merchant_id=$1");
+  qs = GNUNET_PQ_eval_prepared_multi_select (pg->conn,
+                                             "lookup_products",
+                                             params,
+                                             &lookup_products_cb,
+                                             &plc);
+  /* If there was an error inside lookup_products_cb, return a hard error. */
+  if (plc.extract_failed)
+    return GNUNET_DB_STATUS_HARD_ERROR;
+  return qs;
+}
diff --git a/src/backenddb/pg_lookup_products.h b/src/backenddb/pg_lookup_products.h
new file mode 100644
index 00000000..398b5eac
--- /dev/null
+++ b/src/backenddb/pg_lookup_products.h
@@ -0,0 +1,43 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2022 Taler Systems SA
+
+   TALER is free software; you can redistribute it and/or modify it under the
+   terms of the GNU General Public License as published by the Free Software
+   Foundation; either version 3, or (at your option) any later version.
+
+   TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along with
+   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+/**
+ * @file backenddb/pg_lookup_products.h
+ * @brief implementation of the lookup_products function for Postgres
+ * @author Iván Ávalos
+ */
+#ifndef PG_LOOKUP_PRODUCTS_H
+#define PG_LOOKUP_PRODUCTS_H
+
+#include <taler/taler_util.h>
+#include <taler/taler_json_lib.h>
+#include "taler_merchantdb_plugin.h"
+
+/**
+ * Lookup all of the products the given instance has configured.
+ *
+ * @param cls closure
+ * @param instance_id instance to lookup products for
+ * @param cb function to call on all products found
+ * @param cb_cls closure for @a cb
+ * @return database result code
+ */
+enum GNUNET_DB_QueryStatus
+TMH_PG_lookup_products (void *cls,
+                        const char *instance_id,
+                        TALER_MERCHANTDB_ProductsCallback cb,
+                        void *cb_cls);
+
+#endif
diff --git a/src/backenddb/pg_update_product.c b/src/backenddb/pg_update_product.c
new file mode 100644
index 00000000..b571a8fe
--- /dev/null
+++ b/src/backenddb/pg_update_product.c
@@ -0,0 +1,85 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2022 Taler Systems SA
+
+   TALER is free software; you can redistribute it and/or modify it under the
+   terms of the GNU General Public License as published by the Free Software
+   Foundation; either version 3, or (at your option) any later version.
+
+   TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along with
+   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+/**
+ * @file backenddb/pg_update_product.c
+ * @brief Implementation of the update_product function for Postgres
+ * @author Iván Ávalos
+ */
+#include "platform.h"
+#include <taler/taler_error_codes.h>
+#include <taler/taler_dbevents.h>
+#include <taler/taler_pq_lib.h>
+#include "pg_update_product.h"
+#include "pg_helper.h"
+
+enum GNUNET_DB_QueryStatus
+TMH_PG_update_product (void *cls,
+                       const char *instance_id,
+                       const char *product_id,
+                       const struct TALER_MERCHANTDB_ProductDetails *pd)
+{
+  struct PostgresClosure *pg = cls;
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_string (instance_id), /* $1 */
+    GNUNET_PQ_query_param_string (product_id),
+    GNUNET_PQ_query_param_string (pd->description),
+    TALER_PQ_query_param_json (pd->description_i18n),
+    GNUNET_PQ_query_param_string (pd->unit),
+    GNUNET_PQ_query_param_string (pd->image), /* $6 */
+    TALER_PQ_query_param_json (pd->taxes),
+    TALER_PQ_query_param_amount (&pd->price), /* $8+$9 */
+    GNUNET_PQ_query_param_uint64 (&pd->total_stock),  /* $10 */
+    GNUNET_PQ_query_param_uint64 (&pd->total_lost),
+    TALER_PQ_query_param_json (pd->address),
+    GNUNET_PQ_query_param_timestamp (&pd->next_restock),
+    GNUNET_PQ_query_param_uint32 (&pd->minimum_age),
+    GNUNET_PQ_query_param_end
+  };
+
+  if ( (pd->total_stock < pd->total_lost + pd->total_sold) ||
+       (pd->total_lost < pd->total_lost
+        + pd->total_sold) /* integer overflow */)
+  {
+    GNUNET_break (0);
+    return GNUNET_DB_STATUS_HARD_ERROR;
+  }
+  check_connection (pg);
+  PREPARE (pg,
+           "update_product",
+           "UPDATE merchant_inventory SET"
+           " description=$3"
+           ",description_i18n=$4"
+           ",unit=$5"
+           ",image=$6"
+           ",taxes=$7"
+           ",price_val=$8"
+           ",price_frac=$9"
+           ",total_stock=$10"
+           ",total_lost=$11"
+           ",address=$12"
+           ",next_restock=$13"
+           ",minimum_age=$14"
+           " WHERE merchant_serial="
+           "   (SELECT merchant_serial"
+           "      FROM merchant_instances"
+           "      WHERE merchant_id=$1)"
+           "   AND product_id=$2"
+           "   AND total_stock <= $10"
+           "   AND total_lost <= $11");
+  return GNUNET_PQ_eval_prepared_non_select (pg->conn,
+                                             "update_product",
+                                             params);
+}
diff --git a/src/backenddb/pg_update_product.h b/src/backenddb/pg_update_product.h
new file mode 100644
index 00000000..3ad280ef
--- /dev/null
+++ b/src/backenddb/pg_update_product.h
@@ -0,0 +1,53 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2022 Taler Systems SA
+
+   TALER is free software; you can redistribute it and/or modify it under the
+   terms of the GNU General Public License as published by the Free Software
+   Foundation; either version 3, or (at your option) any later version.
+
+   TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along with
+   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+/**
+ * @file backenddb/pg_update_product.h
+ * @brief implementation of the update_product function for Postgres
+ * @author Christian Grothoff
+ */
+#ifndef PG_UPDATE_PRODUCT_H
+#define PG_UPDATE_PRODUCT_H
+
+#include <taler/taler_util.h>
+#include <taler/taler_json_lib.h>
+#include "taler_merchantdb_plugin.h"
+
+/**
+ * Update details about a particular product. Note that the
+ * transaction must enforce that the sold/stocked/lost counters
+ * are not reduced (i.e. by expanding the WHERE clause on the existing
+ * values).
+ *
+ * @param cls closure
+ * @param instance_id instance to lookup products for
+ * @param product_id product to lookup
+ * @param[out] pd set to the product details on success, can be NULL
+ *             (in that case we only want to check if the product exists)
+ *             total_sold in @a pd is ignored, total_lost must not
+ *             exceed total_stock minus the existing total_sold;
+ *             total_sold and total_stock must be larger or equal to
+ *             the existing value;
+ * @return database result code, #GNUNET_DB_STATUS_SUCCESS_NO_RESULTS if the
+ *         non-decreasing constraints are not met *or* if the product
+ *         does not yet exist.
+ */
+enum GNUNET_DB_QueryStatus
+TMH_PG_update_product (void *cls,
+                       const char *instance_id,
+                       const char *product_id,
+                       const struct TALER_MERCHANTDB_ProductDetails *pd);
+
+#endif
diff --git a/src/backenddb/plugin_merchantdb_postgres.c b/src/backenddb/plugin_merchantdb_postgres.c
index 0e0e7abb..0e5f921f 100644
--- a/src/backenddb/plugin_merchantdb_postgres.c
+++ b/src/backenddb/plugin_merchantdb_postgres.c
@@ -53,6 +53,12 @@
 #include "pg_update_instance_auth.h"
 #include "pg_inactivate_account.h"
 #include "pg_activate_account.h"
+#include "pg_lookup_products.h"
+#include "pg_lookup_product.h"
+#include "pg_delete_product.h"
+#include "pg_insert_product.h"
+#include "pg_update_product.h"
+#include "pg_lock_product.h"
 #include "pg_set_transfer_status_to_confirmed.h"
 
 
@@ -331,346 +337,6 @@ postgres_commit (void *cls)
 
 
 /**
- * Context used for postgres_lookup_products().
- */
-struct LookupProductsContext
-{
-  /**
-   * Function to call with the results.
-   */
-  TALER_MERCHANTDB_ProductsCallback cb;
-
-  /**
-   * Closure for @a cb.
-   */
-  void *cb_cls;
-
-  /**
-   * Did database result extraction fail?
-   */
-  bool extract_failed;
-};
-
-
-/**
- * Function to be called with the results of a SELECT statement
- * that has returned @a num_results results about products.
- *
- * @param[in,out] cls of type `struct LookupProductsContext *`
- * @param result the postgres result
- * @param num_results the number of results in @a result
- */
-static void
-lookup_products_cb (void *cls,
-                    PGresult *result,
-                    unsigned int num_results)
-{
-  struct LookupProductsContext *plc = cls;
-
-  for (unsigned int i = 0; i < num_results; i++)
-  {
-    char *product_id;
-    struct GNUNET_PQ_ResultSpec rs[] = {
-      GNUNET_PQ_result_spec_string ("product_id",
-                                    &product_id),
-      GNUNET_PQ_result_spec_end
-    };
-
-    if (GNUNET_OK !=
-        GNUNET_PQ_extract_result (result,
-                                  rs,
-                                  i))
-    {
-      GNUNET_break (0);
-      plc->extract_failed = true;
-      return;
-    }
-    plc->cb (plc->cb_cls,
-             product_id);
-    GNUNET_PQ_cleanup_result (rs);
-  }
-}
-
-
-/**
- * Lookup all of the products the given instance has configured.
- *
- * @param cls closure
- * @param instance_id instance to lookup products for
- * @param cb function to call on all products found
- * @param cb_cls closure for @a cb
- * @return database result code
- */
-static enum GNUNET_DB_QueryStatus
-postgres_lookup_products (void *cls,
-                          const char *instance_id,
-                          TALER_MERCHANTDB_ProductsCallback cb,
-                          void *cb_cls)
-{
-  struct PostgresClosure *pg = cls;
-  struct LookupProductsContext plc = {
-    .cb = cb,
-    .cb_cls = cb_cls,
-    /* Can be overwritten by the lookup_products_cb */
-    .extract_failed = false,
-  };
-  struct GNUNET_PQ_QueryParam params[] = {
-    GNUNET_PQ_query_param_string (instance_id),
-    GNUNET_PQ_query_param_end
-  };
-  enum GNUNET_DB_QueryStatus qs;
-
-  check_connection (pg);
-  qs = GNUNET_PQ_eval_prepared_multi_select (pg->conn,
-                                             "lookup_products",
-                                             params,
-                                             &lookup_products_cb,
-                                             &plc);
-  /* If there was an error inside lookup_products_cb, return a hard error. */
-  if (plc.extract_failed)
-    return GNUNET_DB_STATUS_HARD_ERROR;
-  return qs;
-}
-
-
-/**
- * Lookup details about a particular product.
- *
- * @param cls closure
- * @param instance_id instance to lookup products for
- * @param product_id product to lookup
- * @param[out] pd set to the product details on success, can be NULL
- *             (in that case we only want to check if the product exists)
- * @return database result code
- */
-static enum GNUNET_DB_QueryStatus
-postgres_lookup_product (void *cls,
-                         const char *instance_id,
-                         const char *product_id,
-                         struct TALER_MERCHANTDB_ProductDetails *pd)
-{
-  struct PostgresClosure *pg = cls;
-  struct GNUNET_PQ_QueryParam params[] = {
-    GNUNET_PQ_query_param_string (instance_id),
-    GNUNET_PQ_query_param_string (product_id),
-    GNUNET_PQ_query_param_end
-  };
-
-  if (NULL == pd)
-  {
-    struct GNUNET_PQ_ResultSpec rs_null[] = {
-      GNUNET_PQ_result_spec_end
-    };
-
-    check_connection (pg);
-    return GNUNET_PQ_eval_prepared_singleton_select (pg->conn,
-                                                     "lookup_product",
-                                                     params,
-                                                     rs_null);
-  }
-  else
-  {
-    struct GNUNET_PQ_ResultSpec rs[] = {
-      GNUNET_PQ_result_spec_string ("description",
-                                    &pd->description),
-      TALER_PQ_result_spec_json ("description_i18n",
-                                 &pd->description_i18n),
-      GNUNET_PQ_result_spec_string ("unit",
-                                    &pd->unit),
-      TALER_PQ_RESULT_SPEC_AMOUNT ("price",
-                                   &pd->price),
-      TALER_PQ_result_spec_json ("taxes",
-                                 &pd->taxes),
-      GNUNET_PQ_result_spec_uint64 ("total_stock",
-                                    &pd->total_stock),
-      GNUNET_PQ_result_spec_uint64 ("total_sold",
-                                    &pd->total_sold),
-      GNUNET_PQ_result_spec_uint64 ("total_lost",
-                                    &pd->total_lost),
-      GNUNET_PQ_result_spec_string ("image",
-                                    &pd->image),
-      TALER_PQ_result_spec_json ("address",
-                                 &pd->address),
-      GNUNET_PQ_result_spec_timestamp ("next_restock",
-                                       &pd->next_restock),
-      GNUNET_PQ_result_spec_uint32 ("minimum_age",
-                                    &pd->minimum_age),
-      GNUNET_PQ_result_spec_end
-    };
-
-    check_connection (pg);
-    return GNUNET_PQ_eval_prepared_singleton_select (pg->conn,
-                                                     "lookup_product",
-                                                     params,
-                                                     rs);
-  }
-}
-
-
-/**
- * Delete information about a product.  Note that the transaction must
- * enforce that no stocks are currently locked.
- *
- * @param cls closure
- * @param instance_id instance to delete product of
- * @param product_id product to delete
- * @return DB status code, #GNUNET_DB_STATUS_SUCCESS_NO_RESULTS
- *           if locks prevent deletion OR product unknown
- */
-static enum GNUNET_DB_QueryStatus
-postgres_delete_product (void *cls,
-                         const char *instance_id,
-                         const char *product_id)
-{
-  struct PostgresClosure *pg = cls;
-  struct GNUNET_PQ_QueryParam params[] = {
-    GNUNET_PQ_query_param_string (instance_id),
-    GNUNET_PQ_query_param_string (product_id),
-    GNUNET_PQ_query_param_end
-  };
-
-  check_connection (pg);
-  return GNUNET_PQ_eval_prepared_non_select (pg->conn,
-                                             "delete_product",
-                                             params);
-}
-
-
-/**
- * Insert details about a particular product.
- *
- * @param cls closure
- * @param instance_id instance to insert product for
- * @param product_id product identifier of product to insert
- * @param pd the product details to insert
- * @return database result code
- */
-static enum GNUNET_DB_QueryStatus
-postgres_insert_product (void *cls,
-                         const char *instance_id,
-                         const char *product_id,
-                         const struct TALER_MERCHANTDB_ProductDetails *pd)
-{
-  struct PostgresClosure *pg = cls;
-  struct GNUNET_PQ_QueryParam params[] = {
-    GNUNET_PQ_query_param_string (instance_id),
-    GNUNET_PQ_query_param_string (product_id),
-    GNUNET_PQ_query_param_string (pd->description),
-    TALER_PQ_query_param_json (pd->description_i18n),
-    GNUNET_PQ_query_param_string (pd->unit),
-    GNUNET_PQ_query_param_string (pd->image),
-    TALER_PQ_query_param_json (pd->taxes),
-    TALER_PQ_query_param_amount (&pd->price),
-    GNUNET_PQ_query_param_uint64 (&pd->total_stock),
-    TALER_PQ_query_param_json (pd->address),
-    GNUNET_PQ_query_param_timestamp (&pd->next_restock),
-    GNUNET_PQ_query_param_uint32 (&pd->minimum_age),
-    GNUNET_PQ_query_param_end
-  };
-
-  check_connection (pg);
-  return GNUNET_PQ_eval_prepared_non_select (pg->conn,
-                                             "insert_product",
-                                             params);
-}
-
-
-/**
- * Update details about a particular product. Note that the
- * transaction must enforce that the sold/stocked/lost counters
- * are not reduced (i.e. by expanding the WHERE clause on the existing
- * values).
- *
- * @param cls closure
- * @param instance_id instance to lookup products for
- * @param product_id product to lookup
- * @param[out] pd set to the product details on success, can be NULL
- *             (in that case we only want to check if the product exists)
- *             total_sold in @a pd is ignored, total_lost must not
- *             exceed total_stock minus the existing total_sold;
- *             total_sold and total_stock must be larger or equal to
- *             the existing value;
- * @return database result code, #GNUNET_DB_STATUS_SUCCESS_NO_RESULTS if the
- *         non-decreasing constraints are not met *or* if the product
- *         does not yet exist.
- */
-static enum GNUNET_DB_QueryStatus
-postgres_update_product (void *cls,
-                         const char *instance_id,
-                         const char *product_id,
-                         const struct TALER_MERCHANTDB_ProductDetails *pd)
-{
-  struct PostgresClosure *pg = cls;
-  struct GNUNET_PQ_QueryParam params[] = {
-    GNUNET_PQ_query_param_string (instance_id), /* $1 */
-    GNUNET_PQ_query_param_string (product_id),
-    GNUNET_PQ_query_param_string (pd->description),
-    TALER_PQ_query_param_json (pd->description_i18n),
-    GNUNET_PQ_query_param_string (pd->unit),
-    GNUNET_PQ_query_param_string (pd->image), /* $6 */
-    TALER_PQ_query_param_json (pd->taxes),
-    TALER_PQ_query_param_amount (&pd->price), /* $8+$9 */
-    GNUNET_PQ_query_param_uint64 (&pd->total_stock),  /* $10 */
-    GNUNET_PQ_query_param_uint64 (&pd->total_lost),
-    TALER_PQ_query_param_json (pd->address),
-    GNUNET_PQ_query_param_timestamp (&pd->next_restock),
-    GNUNET_PQ_query_param_uint32 (&pd->minimum_age),
-    GNUNET_PQ_query_param_end
-  };
-
-  if ( (pd->total_stock < pd->total_lost + pd->total_sold) ||
-       (pd->total_lost < pd->total_lost
-        + pd->total_sold) /* integer overflow */)
-  {
-    GNUNET_break (0);
-    return GNUNET_DB_STATUS_HARD_ERROR;
-  }
-  check_connection (pg);
-  return GNUNET_PQ_eval_prepared_non_select (pg->conn,
-                                             "update_product",
-                                             params);
-}
-
-
-/**
- * Lock stocks of a particular product. Note that the transaction must
- * enforce that the "stocked-sold-lost >= locked" constraint holds.
- *
- * @param cls closure
- * @param instance_id instance to lookup products for
- * @param product_id product to lookup
- * @param uuid the UUID that holds the lock
- * @param quantity how many units should be locked
- * @param expiration_time when should the lock expire
- * @return database result code, #GNUNET_DB_STATUS_SUCCESS_NO_RESULTS if the
- *         product is unknown OR if there insufficient stocks remaining
- */
-static enum GNUNET_DB_QueryStatus
-postgres_lock_product (void *cls,
-                       const char *instance_id,
-                       const char *product_id,
-                       const struct GNUNET_Uuid *uuid,
-                       uint64_t quantity,
-                       struct GNUNET_TIME_Timestamp expiration_time)
-{
-  struct PostgresClosure *pg = cls;
-  struct GNUNET_PQ_QueryParam params[] = {
-    GNUNET_PQ_query_param_string (instance_id),
-    GNUNET_PQ_query_param_string (product_id),
-    GNUNET_PQ_query_param_auto_from_type (uuid),
-    GNUNET_PQ_query_param_uint64 (&quantity),
-    GNUNET_PQ_query_param_timestamp (&expiration_time),
-    GNUNET_PQ_query_param_end
-  };
-
-  check_connection (pg);
-  return GNUNET_PQ_eval_prepared_non_select (pg->conn,
-                                             "lock_product",
-                                             params);
-}
-
-
-/**
  * Release all expired product locks, including
  * those from expired offers -- across all
  * instances.
@@ -6540,119 +6206,6 @@ postgres_connect (void *cls)
   struct GNUNET_PQ_PreparedStatement ps[] = {
     GNUNET_PQ_make_prepare ("end_transaction",
                             "COMMIT"),
-    /* for postgres_lookup_products() */
-    GNUNET_PQ_make_prepare ("lookup_products",
-                            "SELECT"
-                            " product_id"
-                            " FROM merchant_inventory"
-                            " JOIN merchant_instances"
-                            "   USING (merchant_serial)"
-                            " WHERE merchant_instances.merchant_id=$1"),
-    /* for postgres_lookup_product() */
-    GNUNET_PQ_make_prepare ("lookup_product",
-                            "SELECT"
-                            " description"
-                            ",description_i18n"
-                            ",unit"
-                            ",price_val"
-                            ",price_frac"
-                            ",taxes"
-                            ",total_stock"
-                            ",total_sold"
-                            ",total_lost"
-                            ",image"
-                            ",merchant_inventory.address"
-                            ",next_restock"
-                            ",minimum_age"
-                            " FROM merchant_inventory"
-                            " JOIN merchant_instances"
-                            "   USING (merchant_serial)"
-                            " WHERE merchant_instances.merchant_id=$1"
-                            "   AND merchant_inventory.product_id=$2"),
-    /* for postgres_delete_product() */
-    GNUNET_PQ_make_prepare ("delete_product",
-                            "DELETE"
-                            " FROM merchant_inventory"
-                            " WHERE merchant_inventory.merchant_serial="
-                            "     (SELECT merchant_serial "
-                            "        FROM merchant_instances"
-                            "        WHERE merchant_id=$1)"
-                            "   AND merchant_inventory.product_id=$2"
-                            "   AND product_serial NOT IN "
-                            "     (SELECT product_serial FROM merchant_order_locks)"
-                            "   AND product_serial NOT IN "
-                            "     (SELECT product_serial FROM merchant_inventory_locks)"),
-    /* for postgres_insert_product() */
-    GNUNET_PQ_make_prepare ("insert_product",
-                            "INSERT INTO merchant_inventory"
-                            "(merchant_serial"
-                            ",product_id"
-                            ",description"
-                            ",description_i18n"
-                            ",unit"
-                            ",image"
-                            ",taxes"
-                            ",price_val"
-                            ",price_frac"
-                            ",total_stock"
-                            ",address"
-                            ",next_restock"
-                            ",minimum_age"
-                            ")"
-                            " SELECT merchant_serial,"
-                            " $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13"
-                            " FROM merchant_instances"
-                            " WHERE merchant_id=$1"),
-    /* for postgres_update_product() */
-    GNUNET_PQ_make_prepare ("update_product",
-                            "UPDATE merchant_inventory SET"
-                            " description=$3"
-                            ",description_i18n=$4"
-                            ",unit=$5"
-                            ",image=$6"
-                            ",taxes=$7"
-                            ",price_val=$8"
-                            ",price_frac=$9"
-                            ",total_stock=$10"
-                            ",total_lost=$11"
-                            ",address=$12"
-                            ",next_restock=$13"
-                            ",minimum_age=$14"
-                            " WHERE merchant_serial="
-                            "   (SELECT merchant_serial"
-                            "      FROM merchant_instances"
-                            "      WHERE merchant_id=$1)"
-                            "   AND product_id=$2"
-                            "   AND total_stock <= $10"
-                            "   AND total_lost <= $11"),
-
-    /* for postgres_lock_product() */
-    GNUNET_PQ_make_prepare ("lock_product",
-                            "WITH ps AS"
-                            "  (SELECT product_serial"
-                            "   FROM merchant_inventory"
-                            "   WHERE product_id=$2"
-                            "     AND merchant_serial="
-                            "     (SELECT merchant_serial"
-                            "        FROM merchant_instances"
-                            "        WHERE merchant_id=$1))"
-                            "INSERT INTO merchant_inventory_locks"
-                            "(product_serial"
-                            ",lock_uuid"
-                            ",total_locked"
-                            ",expiration)"
-                            " SELECT product_serial, $3, $4, $5"
-                            "   FROM merchant_inventory"
-                            "   JOIN ps USING (product_serial)"
-                            "   WHERE "
-                            "     total_stock - total_sold - total_lost - $4 >= "
-                            "     (SELECT COALESCE(SUM(total_locked), 0)"
-                            "        FROM merchant_inventory_locks"
-                            "        WHERE product_serial=ps.product_serial) + "
-                            "     (SELECT COALESCE(SUM(total_locked), 0)"
-                            "        FROM merchant_order_locks"
-                            "        WHERE product_serial=ps.product_serial)"),
-
     /* for postgres_expire_locks() */
     GNUNET_PQ_make_prepare ("unlock_products",
                             "DELETE FROM merchant_inventory_locks"
@@ -8861,12 +8414,18 @@ libtaler_plugin_merchantdb_postgres_init (void *cls)
     = &TMH_PG_inactivate_account;
   plugin->update_transfer_status
     = &TMH_PG_update_transfer_status;
-  plugin->lookup_products = &postgres_lookup_products;
-  plugin->lookup_product = &postgres_lookup_product;
-  plugin->delete_product = &postgres_delete_product;
-  plugin->insert_product = &postgres_insert_product;
-  plugin->update_product = &postgres_update_product;
-  plugin->lock_product = &postgres_lock_product;
+  plugin->lookup_products
+    = &TMH_PG_lookup_products;
+  plugin->lookup_product
+    = &TMH_PG_lookup_product;
+  plugin->delete_product
+    = &TMH_PG_delete_product;
+  plugin->insert_product
+    = &TMH_PG_insert_product;
+  plugin->update_product
+    = &TMH_PG_update_product;
+  plugin->lock_product
+    = &TMH_PG_lock_product;
   plugin->expire_locks = &postgres_expire_locks;
   plugin->delete_order = &postgres_delete_order;
   plugin->lookup_order = &postgres_lookup_order;