add partitions to new p2p tables

src/exchangedb/exchangedb.conf

@@ -26,3 +26,7 @@ IDLE_RESERVE_EXPIRATION_TIME = 4 weeks
 # After how long do we forget about reserves?  Should be above
 # the legal expiration timeframe of withdrawn coins.
 LEGAL_RESERVE_EXPIRATION_TIME = 7 years
+
+# What is the desired delay between a transaction being ready and the
+# aggregator triggering on it?
+AGGREGATOR_SHIFT = 1 s

src/exchangedb/partition-0001.sql

@@ -229,6 +229,28 @@ BEGIN
     );
     PERFORM add_constraints_to_deposits_partition(num_partitions::varchar);
 
+-- TODO: dynamically (!) creating/deleting deposits partitions:
+--    create new partitions 'as needed', drop old ones once the aggregator has made
+--    them empty; as 'new' deposits will always have deadlines in the future, this
+--    would basically guarantee no conflict between aggregator and exchange service!
+-- SEE also: https://www.cybertec-postgresql.com/en/automatic-partition-creation-in-postgresql/
+-- (article is slightly wrong, as this works:)
+--CREATE TABLE tab (
+--  id bigint GENERATED ALWAYS AS IDENTITY,
+--  ts timestamp NOT NULL,
+--  data text
+-- PARTITION BY LIST ((ts::date));
+-- CREATE TABLE tab_def PARTITION OF tab DEFAULT;
+-- BEGIN
+-- CREATE TABLE tab_part2 (LIKE tab);
+-- insert into tab_part2 (id,ts, data) values (5,'2022-03-21', 'foo');
+-- alter table tab attach partition tab_part2 for values in ('2022-03-21');
+-- commit;
+-- Naturally, to ensure this is actually 100% conflict-free, we'd
+-- need to create tables at the granularity of the wire/refund deadlines;
+-- that is right now configurable via AGGREGATOR_SHIFT option.
+
+
     PERFORM create_table_partition(
       'refunds'
       ,modulus
@@ -287,4 +309,4 @@ BEGIN
 END
 $$;
 
-COMMIT;
+COMMIT;

src/exchangedb/plugin_exchangedb_postgres.c

@@ -115,6 +115,12 @@ struct PostgresClosure
    */
   struct GNUNET_TIME_Relative legal_reserve_expiration_time;
 
+  /**
+   * What delay should we introduce before ready transactions
+   * are actually aggregated?
+   */
+  struct GNUNET_TIME_Relative aggregator_shift;
+
   /**
    * Which currency should we assume all amounts to be in?
    */
@@ -5993,7 +5999,8 @@ postgres_get_ready_deposit (void *cls,
   };
   enum GNUNET_DB_QueryStatus qs;
 
-  now = GNUNET_TIME_absolute_get ();
+  now = GNUNET_TIME_absolute_round_down (GNUNET_TIME_absolute_get (),
+                                         pg->aggregator_shift);
   GNUNET_assert (start_shard_row < end_shard_row);
   GNUNET_assert (end_shard_row <= INT32_MAX);
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
@@ -6154,7 +6161,7 @@ postgres_iterate_matching_deposits (
   uint32_t limit)
 {
   struct PostgresClosure *pg = cls;
-  struct GNUNET_TIME_Absolute now = GNUNET_TIME_absolute_get ();
+  struct GNUNET_TIME_Absolute now = {0};
   uint64_t shard = compute_shard (merchant_pub);
   struct GNUNET_PQ_QueryParam params[] = {
     GNUNET_PQ_query_param_auto_from_type (merchant_pub),
@@ -6173,6 +6180,8 @@ postgres_iterate_matching_deposits (
   };
   enum GNUNET_DB_QueryStatus qs;
 
+  now = GNUNET_TIME_absolute_round_down (GNUNET_TIME_absolute_get (),
+                                         pg->aggregator_shift);
   qs = GNUNET_PQ_eval_prepared_multi_select (pg->conn,
                                              "deposits_iterate_matching",
                                              params,
@@ -13012,6 +13021,17 @@ libtaler_plugin_exchangedb_postgres_init (void *cls)
     GNUNET_free (pg);
     return NULL;
   }
+  if (GNUNET_OK !=
+      GNUNET_CONFIGURATION_get_value_time (cfg,
+                                           "exchangedb",
+                                           "AGGREGATOR_SHIFT",
+                                           &pg->aggregator_shift))
+  {
+    GNUNET_log_config_missing (GNUNET_ERROR_TYPE_WARNING,
+                               "exchangedb",
+                               "AGGREGATOR_SHIFT");
+  }
+
   if (GNUNET_OK !=
       TALER_config_get_currency (cfg,
                                  &pg->currency))

src/exchangedb/test-exchange-db-postgres.conf

@@ -28,3 +28,6 @@ IDLE_RESERVE_EXPIRATION_TIME = 4 weeks
 # After how long do we forget about reserves?  Should be above
 # the legal expiration timeframe of withdrawn coins.
 LEGAL_RESERVE_EXPIRATION_TIME = 7 years
+
+# Shift to apply before aggregating.
+AGGREGATOR_SHIFT = 1s