Optimize metrics import and split off metrics import functions (untested)

inventory-server/db/schema.sql

@@ -30,10 +30,31 @@ CREATE TABLE IF NOT EXISTS products (
     INDEX idx_brand (brand)
 );
 
+-- Temporary tables for batch metrics processing
+CREATE TABLE IF NOT EXISTS temp_sales_metrics (
+    product_id BIGINT NOT NULL,
+    daily_sales_avg DECIMAL(10,3),
+    weekly_sales_avg DECIMAL(10,3),
+    monthly_sales_avg DECIMAL(10,3),
+    total_revenue DECIMAL(10,3),
+    avg_margin_percent DECIMAL(10,3),
+    first_sale_date DATE,
+    last_sale_date DATE,
+    PRIMARY KEY (product_id)
+);
+
+CREATE TABLE IF NOT EXISTS temp_purchase_metrics (
+    product_id BIGINT NOT NULL,
+    avg_lead_time_days INT,
+    last_purchase_date DATE,
+    last_received_date DATE,
+    PRIMARY KEY (product_id)
+);
+
 -- New table for product metrics
 CREATE TABLE IF NOT EXISTS product_metrics (
     product_id BIGINT NOT NULL,
-    last_calculated_at TIMESTAMP NOT NULL,
+    last_calculated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
     -- Sales velocity metrics
     daily_sales_avg DECIMAL(10,3),
     weekly_sales_avg DECIMAL(10,3),
@@ -57,6 +78,10 @@ CREATE TABLE IF NOT EXISTS product_metrics (
     FOREIGN KEY (product_id) REFERENCES products(product_id) ON DELETE CASCADE
 );
 
+-- Optimized indexes for metrics calculations
+CREATE INDEX idx_orders_metrics ON orders (product_id, date, canceled, quantity, price);
+CREATE INDEX idx_purchase_orders_metrics ON purchase_orders (product_id, date, status, ordered, received);
+
 -- New table for time-based aggregates
 CREATE TABLE IF NOT EXISTS product_time_aggregates (
     product_id BIGINT NOT NULL,