Add AggsUTXOs table

Users who use a wallet want to know which amount of assets they
have. The indexer was calculating the data using an aggregation
query. The aggregation query was slow as the aggregation query should
scan the UTXOs.

To make the query faster, we can make a table that has pre-calculated
asset amounts.

This commit creates the AggsUTXOs table. This table contains the
pre-calculated the amounts of assets. For the data consistency, we are
using the PostgreSQL's trigger feature to update the quantities.

Author: majecty

src/migrations/20191115032739-add-aggs-utxo-table.js

@@ -0,0 +1,96 @@
+"use strict";
+
+module.exports = {
+    up: async (queryInterface, Sequelize) => {
+        await queryInterface.createTable("AggsUTXOs", {
+            id: {
+                allowNull: false,
+                autoIncrement: true,
+                primaryKey: true,
+                type: Sequelize.BIGINT
+            },
+            address: {
+                allowNull: false,
+                type: Sequelize.STRING
+            },
+            assetType: {
+                allowNull: false,
+                type: Sequelize.STRING
+            },
+            totalAssetQuantity: {
+                allowNull: false,
+                type: Sequelize.BIGINT,
+                defaultValue: 0
+            },
+            utxoQuantity: {
+                allowNull: false,
+                type: Sequelize.BIGINT,
+                defaultValue: 0
+            },
+            createdAt: {
+                allowNull: false,
+                type: Sequelize.DATE
+            },
+            updatedAt: {
+                allowNull: false,
+                type: Sequelize.DATE
+            }
+        });
+
+        await queryInterface.addIndex("AggsUTXOs", {
+            fields: ["address", "assetType"],
+            unique: true
+        });
+
+        await queryInterface.sequelize.query(`
+        CREATE FUNCTION utxos_trigger_function() RETURNS trigger
+        LANGUAGE plpgsql
+            as
+            $$
+                BEGIN
+                    IF (TG_OP = 'INSERT') THEN
+                        IF NEW."usedBlockNumber" IS NULL THEN
+                            INSERT INTO "AggsUTXOs"("assetType", address, "totalAssetQuantity", "utxoQuantity", "createdAt", "updatedAt") VALUES(NEW."assetType", NEW.address, NEW.quantity, 1, NOW(), NOW())
+                            ON CONFLICT ("assetType", "address") DO UPDATE SET "totalAssetQuantity"="AggsUTXOs"."totalAssetQuantity"+NEW."quantity", "utxoQuantity"="AggsUTXOs"."utxoQuantity"+1;
+                        END IF;
+                        return NEW;
+                    ELSEIF (TG_OP = 'UPDATE') THEN
+                        IF OLD."usedBlockNumber" IS NULL THEN
+                            UPDATE "AggsUTXOs" SET "totalAssetQuantity"="totalAssetQuantity"-OLD.quantity, "utxoQuantity"="utxoQuantity"-1, "updatedAt"=NOW() WHERE "AggsUTXOs".address=OLD.address AND "AggsUTXOs"."assetType"=OLD."assetType";
+                        END IF;
+                        IF NEW."usedBlockNumber" IS NULL THEN
+                            INSERT INTO "AggsUTXOs"("assetType", address, "totalAssetQuantity", "utxoQuantity", "createdAt", "updatedAt") VALUES(NEW."assetType", NEW.address, NEW.quantity, 1, NOW(), NOW())
+                            ON CONFLICT ("assetType", "address") DO UPDATE SET "totalAssetQuantity"="AggsUTXOs"."totalAssetQuantity"+NEW.quantity, "utxoQuantity"="AggsUTXOs"."utxoQuantity"+1;
+                        END IF;
+                        RETURN NEW;
+                    ELSEIF (TG_OP = 'DELETE') THEN
+                        IF OLD."usedBlockNumber" IS NULL THEN
+                            UPDATE "AggsUTXOs" SET "totalAssetQuantity"="totalAssetQuantity"-OLD.quantity, "utxoQuantity"="utxoQuantity"-1, "updatedAt"=NOW() WHERE "AggsUTXOs".address=OLD.address AND "AggsUTXOs"."assetType"=OLD."assetType";
+                        END IF;
+                        return OLD;
+                    END IF;
+                END;
+            $$;`);
+        await queryInterface.sequelize.query(`
+        CREATE TRIGGER utxos_trigger
+        AFTER INSERT OR UPDATE OR DELETE
+           ON "UTXOs"
+           FOR EACH ROW
+               EXECUTE PROCEDURE utxos_trigger_function()
+        `);
+
+        await queryInterface.sequelize.query(`
+            INSERT INTO "AggsUTXOs"("assetType", "address", "totalAssetQuantity", "utxoQuantity", "createdAt", "updatedAt") SELECT "assetType", "address", SUM("quantity") as "totalAssetQuantity", COUNT(*) as "utxoQuantity", NOW(), NOW() FROM "UTXOs" GROUP BY "assetType", "address"
+        `);
+    },
+
+    down: async (queryInterface, Sequelize) => {
+        await queryInterface.dropTable("AggsUTXOs");
+        await queryInterface.sequelize.query(
+            `DROP TRIGGER "utxos_trigger" ON "UTXOs"`
+        );
+        await queryInterface.sequelize.query(
+            "DROP FUNCTION utxos_trigger_function()"
+        );
+    }
+};