add extra sort by id in cards list to make it stable for equal values

add a bunch of extra sql indexes to make sure this is performant

resources/migrations/00014_add_better_cards_table_sort_indexes.down.sql

@@ -0,0 +1,23 @@
+DROP INDEX IF EXISTS cards_name_asc_id_idx;
+DROP INDEX IF EXISTS cards_name_desc_id_idx;
+
+DROP INDEX IF EXISTS cards_set_code_asc_id_idx;
+DROP INDEX IF EXISTS cards_set_code_desc_id_idx;
+
+DROP INDEX IF EXISTS cards_converted_mana_cost_nulls_first_asc_id_idx;
+DROP INDEX IF EXISTS cards_converted_mana_cost_nulls_last_desc_id_idx;
+
+DROP INDEX IF EXISTS cards_type_asc_id_idx;
+DROP INDEX IF EXISTS cards_type_desc_id_idx;
+
+DROP INDEX IF EXISTS cards_rarity_asc_id_idx;
+DROP INDEX IF EXISTS cards_rarity_desc_id_idx;
+
+DROP INDEX IF EXISTS cards_paper_price_nulls_first_asc_id_idx;
+DROP INDEX IF EXISTS cards_paper_price_nulls_last_desc_id_idx;
+
+DROP INDEX IF EXISTS cards_online_price_nulls_first_asc_id_idx;
+DROP INDEX IF EXISTS cards_online_price_nulls_last_desc_id_idx;
+
+DROP INDEX IF EXISTS cards_owned_count_asc_id_idx;
+DROP INDEX IF EXISTS cards_owned_count_desc_id_idx;

resources/migrations/00014_add_better_cards_table_sort_indexes.up.sql

@@ -0,0 +1,31 @@
+-- these indexes are to make sure that all the sorting possible via the web UI
+-- is fast and _stable_ across multiple pages of the same value
+-- (e.g. sorting on rarity and navigating through multiple pages of 'Common' values)
+--
+-- of course, these additional indexes don't take care of all possible sorting and filtering
+-- permutations available through the web UI (still possible to end up with some bitmap scans, etc.
+-- in the query plans used in some cases)... but it definitely is better then nothing
+
+CREATE INDEX cards_name_asc_id_idx ON cards (name ASC, id);
+CREATE INDEX cards_name_desc_id_idx ON cards (name DESC, id);
+
+CREATE INDEX cards_set_code_asc_id_idx ON cards (set_code ASC, id);
+CREATE INDEX cards_set_code_desc_id_idx ON cards (set_code DESC, id);
+
+CREATE INDEX cards_converted_mana_cost_nulls_first_asc_id_idx ON cards (converted_mana_cost ASC NULLS FIRST, id);
+CREATE INDEX cards_converted_mana_cost_nulls_last_desc_id_idx ON cards (converted_mana_cost DESC NULLS LAST, id);
+
+CREATE INDEX cards_type_asc_id_idx ON cards (type ASC, id);
+CREATE INDEX cards_type_desc_id_idx ON cards (type DESC, id);
+
+CREATE INDEX cards_rarity_asc_id_idx ON cards (rarity ASC, id);
+CREATE INDEX cards_rarity_desc_id_idx ON cards (rarity DESC, id);
+
+CREATE INDEX cards_paper_price_nulls_first_asc_id_idx ON cards (paper_price ASC NULLS FIRST, id);
+CREATE INDEX cards_paper_price_nulls_last_desc_id_idx ON cards (paper_price DESC NULLS LAST, id);
+
+CREATE INDEX cards_online_price_nulls_first_asc_id_idx ON cards (online_price ASC NULLS FIRST, id);
+CREATE INDEX cards_online_price_nulls_last_desc_id_idx ON cards (online_price DESC NULLS LAST, id);
+
+CREATE INDEX cards_owned_count_asc_id_idx ON cards (owned_count ASC, id);
+CREATE INDEX cards_owned_count_desc_id_idx ON cards (owned_count DESC, id);

src/mtgcoll/views/functions/cards.clj

@@ -212,7 +212,7 @@
                       :from   [[:cards :c]]
                       :join   [[:sets :s] [:= :c.set_code :s.code]]}
                      (if order-by
-                       {:order-by [order-by]}))
+                       {:order-by [order-by [:c.id]]}))
                    :cards_list]]}]
     (if (seq hsql-filters)
       (assoc q :where (concat [:and] hsql-filters))