feat(mysql): add pool size options for each connection (#11810)

Co-authored-by: 아이작_조서환 <wtae1216@sooplive.com>

src/driver/mysql/MysqlConnectionCredentialsOptions.ts

@@ -43,4 +43,10 @@ export interface MysqlConnectionCredentialsOptions {
      * Database socket path
      */
     readonly socketPath?: string
+
+    /**
+     * Maximum number of clients the pool should contain.
+     * for each connection
+     */
+    readonly poolSize?: number
 }

src/driver/mysql/MysqlDriver.ts

@@ -1287,7 +1287,7 @@ export class MysqlDriver implements Driver {
                 port: credentials.port,
                 ssl: options.ssl,
                 socketPath: credentials.socketPath,
-                connectionLimit: options.poolSize,
+                connectionLimit: credentials.poolSize ?? options.poolSize,
             },
             options.acquireTimeout === undefined
                 ? {}