Bug: maxPgConnections config option is ignored in EdgeWorker.start()

[jumski]

Description

The maxPgConnections option passed to EdgeWorker.start() is silently ignored. The SQL connection pool is always created with hardcoded max: 10 regardless of user configuration.

Reproduction

// User expects 4 connections per worker
EdgeWorker.start(GreetUser, { maxPgConnections: 4 });

// But each worker actually creates 10 connections
// With 8 workers: 80 connections instead of expected 32

Root Cause

The issue is in how the SQL client flows through the initialization:

1. EdgeWorker.startFlowWorker() calls createAdapter() without passing maxPgConnections:

   // EdgeWorker.ts:197-200
   const platform = await createAdapter({
     sql: config.sql,
     connectionString: config.connectionString,
     // maxPgConnections is NOT passed here
   });

2. SupabasePlatformAdapter creates SQL via resolveSqlConnection() with hardcoded max: 10:

   // resolveConnection.ts:87, 92, 97
   return postgres(options.connectionString, { prepare: false, max: 10 });

3. EdgeWorker.startFlowWorker() passes platform's SQL to createFlowWorker:

   // EdgeWorker.ts:204-208
   const workerConfig: FlowWorkerConfig = {
     ...config,                           // maxPgConnections: 4 is here
     sql: platform.platformResources.sql, // BUT sql is overwritten with max:10 client
   };

4. createFlowWorker() sees config.sql exists and uses it directly, never checking maxPgConnections:

   // createFlowWorker.ts:71-76
   const sql =
     config.sql ||  // ← truthy (platform SQL with max:10), so used directly
     postgres(config.connectionString, {
       max: config.maxPgConnections ?? 4,  // ← NEVER REACHED
     });

Impact

• Users cannot control connection pool size
• With default max: 10 and multiple workers, connection limits are easily exhausted
• Results in CONNECTION_CLOSED errors and remaining connection slots are reserved for roles with SUPERUSER attribute errors

Proposed Fix

Option A (minimal): Pass maxPgConnections through to resolveSqlConnection():

// resolveConnection.ts - add maxPgConnections parameter
export function resolveSqlConnection(
  env: ConnectionEnv,
  options?: SqlConnectionOptions & { maxPgConnections?: number }
): postgres.Sql {
  const max = options?.maxPgConnections ?? 4;
  
  if (options?.sql) return options.sql;
  if (options?.connectionString) {
    return postgres(options.connectionString, { prepare: false, max });
  }
  // ... etc
}

And update createAdapter() to accept and pass through maxPgConnections.

Option B (cleaner): Don't create SQL in the platform adapter. Let createFlowWorker always create its own SQL connection using the config, and just pass connectionString from the platform.

Environment

• @pgflow/edge-worker (current main branch)
• Discovered while running 8 edge function workers with maxPgConnections: 4 config