Batch processing and error handling improvements

packages/database/prisma/migrations/20241218160237_create_guest_users/migration.sql

@@ -1,51 +1,98 @@
+BEGIN;
+
 -- Create guest users for participants without user_id and link them
 DO $$
 DECLARE
-    participant_record RECORD;
+    v_processed INTEGER := 0;
+    v_total_processed INTEGER := 0;
+    v_batch_size INTEGER := 1000;
 BEGIN
-    FOR participant_record IN 
+    RAISE NOTICE 'Starting participant migration...';
+    
+    -- Process participants in batches
+    LOOP
+        WITH to_process AS (
             SELECT id, name, email 
             FROM participants 
             WHERE user_id IS NULL
-    LOOP
-        WITH new_user AS (
+            LIMIT v_batch_size
+            FOR UPDATE SKIP LOCKED
+        ),
+        new_users AS (
             INSERT INTO users (id, is_guest, created_at)
-            VALUES (
-                gen_random_uuid()::text,
-                TRUE,
-                NOW()
-            )
+            SELECT gen_random_uuid()::text, TRUE, NOW()
+            FROM to_process
             RETURNING id
         )
-        UPDATE participants
-        SET user_id = (SELECT id FROM new_user)
-        WHERE id = participant_record.id;
+        UPDATE participants p
+        SET user_id = u.id
+        FROM (
+            SELECT id, ROW_NUMBER() OVER () as rn
+            FROM new_users
+        ) u
+        WHERE p.id IN (
+            SELECT id FROM to_process
+        )
+        AND p.user_id IS NULL;
+
+        GET DIAGNOSTICS v_processed = ROW_COUNT;
+        v_total_processed := v_total_processed + v_processed;
+        
+        EXIT WHEN v_processed = 0;
+        RAISE NOTICE 'Processed % participants (total: %)', v_processed, v_total_processed;
     END LOOP;
+
+    RAISE NOTICE 'Completed participant migration. Total processed: %', v_total_processed;
 END;
 $$;
 
 -- Create guest users for comments without user_id and link them
 DO $$
 DECLARE
-    comment_record RECORD;
+    v_processed INTEGER := 0;
+    v_total_processed INTEGER := 0;
+    v_batch_size INTEGER := 1000;
 BEGIN
-    FOR comment_record IN 
+    RAISE NOTICE 'Starting comment migration...';
+    
+    -- Process comments in batches
+    LOOP
+        WITH to_process AS (
             SELECT id, author_name
             FROM comments 
             WHERE user_id IS NULL
-    LOOP
-        WITH new_user AS (
+            LIMIT v_batch_size
+            FOR UPDATE SKIP LOCKED
+        ),
+        new_users AS (
             INSERT INTO users (id, is_guest, created_at)
-            VALUES (
-                gen_random_uuid()::text,
-                TRUE,
-                NOW()
-            )
+            SELECT gen_random_uuid()::text, TRUE, NOW()
+            FROM to_process
             RETURNING id
         )
-        UPDATE comments
-        SET user_id = (SELECT id FROM new_user)
-        WHERE id = comment_record.id;
+        UPDATE comments c
+        SET user_id = u.id
+        FROM (
+            SELECT id, ROW_NUMBER() OVER () as rn
+            FROM new_users
+        ) u
+        WHERE c.id IN (
+            SELECT id FROM to_process
+        )
+        AND c.user_id IS NULL;
+
+        GET DIAGNOSTICS v_processed = ROW_COUNT;
+        v_total_processed := v_total_processed + v_processed;
+        
+        EXIT WHEN v_processed = 0;
+        RAISE NOTICE 'Processed % comments (total: %)', v_processed, v_total_processed;
     END LOOP;
+
+    RAISE NOTICE 'Completed comment migration. Total processed: %', v_total_processed;
+EXCEPTION WHEN OTHERS THEN
+    RAISE WARNING 'Error during comment migration: %', SQLERRM;
+    RAISE;
 END;
 $$;
+
+COMMIT;