42 lines
1.3 KiB
Markdown
42 lines
1.3 KiB
Markdown
---
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title: Use Connection Pooling for All Applications
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impact: CRITICAL
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impactDescription: Handle 10-100x more concurrent users
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tags: connection-pooling, pgbouncer, performance, scalability
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---
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## Use Connection Pooling for All Applications
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Postgres connections are expensive (1-3MB RAM each). Without pooling, applications exhaust connections under load.
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**Incorrect (new connection per request):**
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```sql
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-- Each request creates a new connection
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-- Application code: db.connect() per request
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-- Result: 500 concurrent users = 500 connections = crashed database
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-- Check current connections
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select count(*) from pg_stat_activity; -- 487 connections!
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```
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**Correct (connection pooling):**
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```sql
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-- Use a pooler like PgBouncer between app and database
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-- Application connects to pooler, pooler reuses a small pool to Postgres
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-- Configure pool_size based on: (CPU cores * 2) + spindle_count
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-- Example for 4 cores: pool_size = 10
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-- Result: 500 concurrent users share 10 actual connections
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select count(*) from pg_stat_activity; -- 10 connections
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```
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Pool modes:
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- **Transaction mode**: connection returned after each transaction (best for most apps)
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- **Session mode**: connection held for entire session (needed for prepared statements, temp tables)
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Reference: [Connection Pooling](https://supabase.com/docs/guides/database/connecting-to-postgres#connection-pooler)
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