first commit

.agents/skills/supabase-postgres-best-practices/references/conn-prepared-statements.md

@@ -0,0 +1,46 @@
+---
+title: Use Prepared Statements Correctly with Pooling
+impact: HIGH
+impactDescription: Avoid prepared statement conflicts in pooled environments
+tags: prepared-statements, connection-pooling, transaction-mode
+---
+
+## Use Prepared Statements Correctly with Pooling
+
+Prepared statements are tied to individual database connections. In transaction-mode pooling, connections are shared, causing conflicts.
+
+**Incorrect (named prepared statements with transaction pooling):**
+
+```sql
+-- Named prepared statement
+prepare get_user as select * from users where id = $1;
+
+-- In transaction mode pooling, next request may get different connection
+execute get_user(123);
+-- ERROR: prepared statement "get_user" does not exist
+```
+
+**Correct (use unnamed statements or session mode):**
+
+```sql
+-- Option 1: Use unnamed prepared statements (most ORMs do this automatically)
+-- The query is prepared and executed in a single protocol message
+
+-- Option 2: Deallocate after use in transaction mode
+prepare get_user as select * from users where id = $1;
+execute get_user(123);
+deallocate get_user;
+
+-- Option 3: Use session mode pooling (port 5432 vs 6543)
+-- Connection is held for entire session, prepared statements persist
+```
+
+Check your driver settings:
+
+```sql
+-- Many drivers use prepared statements by default
+-- Node.js pg: { prepare: false } to disable
+-- JDBC: prepareThreshold=0 to disable
+```
+
+Reference: [Prepared Statements with Pooling](https://supabase.com/docs/guides/database/connecting-to-postgres#connection-pool-modes)