Add in-app connection string settings

PluralKit.Core/Database/Database.cs

@@ -25,6 +25,7 @@ namespace PluralKit.Core
         private readonly ILogger _logger;
         private readonly IMetrics _metrics;
         private readonly DbConnectionCountHolder _countHolder;
+        private readonly string _connectionString;
 
         public Database(CoreConfig config, DbConnectionCountHolder countHolder, ILogger logger,
                         IMetrics metrics)
@@ -33,6 +34,11 @@ namespace PluralKit.Core
             _countHolder = countHolder;
             _metrics = metrics;
             _logger = logger;
+            
+            _connectionString = new NpgsqlConnectionStringBuilder(_config.Database)
+            {
+                Pooling = true, MaxPoolSize = 500, Enlist = false, NoResetOnClose = true
+            }.ConnectionString;
         }
         
         public static void InitStatic()
@@ -76,7 +82,7 @@ namespace PluralKit.Core
             
             // Create a connection and open it
             // We wrap it in PKConnection for tracing purposes
-            var conn = new PKConnection(new NpgsqlConnection(_config.Database), _countHolder, _logger, _metrics);
+            var conn = new PKConnection(new NpgsqlConnection(_connectionString), _countHolder, _logger, _metrics);
             await conn.OpenAsync();
             return conn;
         }