Delete old states and create a UNIQUE index on states.contract_tx_id #21

src/db/00001_unique_contract_tx_id.sql

@@ -0,0 +1,58 @@
+BEGIN;
+
+-- Remove temp tables in case previous run failed
+DROP TABLE IF EXISTS to_delete_states;
+
+DROP TABLE IF EXISTS max_states;
+
+-- Max sort keys in contracts that have multiple entries
+CREATE TEMP TABLE max_states AS
+SELECT
+    contract_tx_id,
+    MAX(sort_key) as max_sort_key
+FROM
+    states
+GROUP BY
+    contract_tx_id
+HAVING
+    COUNT(*) > 1;
+
+-- States that get removed. PK is contract_tx_id + sort_key
+CREATE TEMP TABLE to_delete_states AS
+SELECT
+    max_states.contract_tx_id,
+    states.sort_key
+FROM
+    states
+    JOIN max_states ON states.contract_tx_id = max_states.contract_tx_id
+WHERE
+    states.sort_key < max_states.max_sort_key;
+
+-- Remove states
+DELETE FROM
+    states
+WHERE
+    EXISTS (
+        SELECT
+            *
+        FROM
+            to_delete_states
+        WHERE
+            to_delete_states.contract_tx_id = states.contract_tx_id
+            AND to_delete_states.sort_key = states.sort_key
+    );
+
+-- There's one entry per contract_tx_id, so we can create a unique index
+CREATE UNIQUE INDEX IF NOT EXISTS states_contract_tx_id_unique ON states(contract_tx_id);
+
+-- Remove the old index
+DROP INDEX IF EXISTS states_contract_tx_id_index;
+
+-- Cleanup
+DROP TABLE to_delete_states;
+
+DROP TABLE max_states;
+
+COMMIT;
+
+VACUUM;

src/db/nodeDb.js

@@ -43,7 +43,7 @@ module.exports = {
     const hasStatesTable = await knex.schema.hasTable('states');
     if (!hasStatesTable) {
       await knex.schema.createTable('states', function (t) {
-        t.string('contract_tx_id').index();
+        t.string('contract_tx_id').unique();
         t.jsonb('manifest').notNullable();
         t.string('bundle_tx_id');
         t.string('sort_key').index();
@@ -60,7 +60,7 @@ module.exports = {
     // Trigger for ensuring only the newest state is stored
     await knex.raw(`
     CREATE TRIGGER IF NOT EXISTS reject_outdated_state
-    BEFORE INSERT
+    BEFORE UPDATE
       ON states
     BEGIN
       SELECT CASE