first commit

.agent/skills/supabase-postgres-best-practices/references/data-pagination.md

@@ -0,0 +1,50 @@
+---
+title: Use Cursor-Based Pagination Instead of OFFSET
+impact: MEDIUM-HIGH
+impactDescription: Consistent O(1) performance regardless of page depth
+tags: pagination, cursor, keyset, offset, performance
+---
+
+## Use Cursor-Based Pagination Instead of OFFSET
+
+OFFSET-based pagination scans all skipped rows, getting slower on deeper pages. Cursor pagination is O(1).
+
+**Incorrect (OFFSET pagination):**
+
+```sql
+-- Page 1: scans 20 rows
+select * from products order by id limit 20 offset 0;
+
+-- Page 100: scans 2000 rows to skip 1980
+select * from products order by id limit 20 offset 1980;
+
+-- Page 10000: scans 200,000 rows!
+select * from products order by id limit 20 offset 199980;
+```
+
+**Correct (cursor/keyset pagination):**
+
+```sql
+-- Page 1: get first 20
+select * from products order by id limit 20;
+-- Application stores last_id = 20
+
+-- Page 2: start after last ID
+select * from products where id > 20 order by id limit 20;
+-- Uses index, always fast regardless of page depth
+
+-- Page 10000: same speed as page 1
+select * from products where id > 199980 order by id limit 20;
+```
+
+For multi-column sorting:
+
+```sql
+-- Cursor must include all sort columns
+select * from products
+where (created_at, id) > ('2024-01-15 10:00:00', 12345)
+order by created_at, id
+limit 20;
+```
+
+Reference: [Pagination](https://supabase.com/docs/guides/database/pagination)