From 09d06bc0857c2f5faec7b1bf70e62d30a9c1bb3d Mon Sep 17 00:00:00 2001
From: Guillermo Pages <mail@guillermo.at>
Date: Thu, 12 Feb 2026 23:28:22 +0100
Subject: [PATCH] fix: add persistent connections + fix self::$pdo bug
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- Add PDO::ATTR_PERSISTENT to prevent SQL Server connection storms
  under concurrent PHP-FPM load (was causing 241 SQLSTATE[08001]
  failures/day on callioapi)
- Fix bug: $pdo → self::$pdo in connect() and getPDOInstance()
  guards (was checking undefined local var instead of static prop)
---
 src/PDOWithFilters/PDOWithFilters.php | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/PDOWithFilters/PDOWithFilters.php b/src/PDOWithFilters/PDOWithFilters.php
index dd387ce..beee684 100644
--- a/src/PDOWithFilters/PDOWithFilters.php
+++ b/src/PDOWithFilters/PDOWithFilters.php
@@ -35,16 +35,16 @@ class PDOWithFilters {
 
 
   public static function connect($dsn, $username, $password) {
-    if (!empty($pdo)) {
+    if (!empty(self::$pdo)) {
       throw new \Exception('Create Pdo only once');
     }
-    self::$pdo = new \PDO($dsn, $username, $password);
+    self::$pdo = new \PDO($dsn, $username, $password, [\PDO::ATTR_PERSISTENT => true]);
 
     return self::$pdo;
   }
 
   public static function getPDOInstance() {
-    if (empty($pdo)) {
+    if (empty(self::$pdo)) {
       throw new \Exception('You must call connect() first');
     }
     return self::$pdo;