From 22bc693d4dc1ab104f3ab0916838853dbb04ab85 Mon Sep 17 00:00:00 2001
From: Vitali Graf <info@vitaligraf.de>
Date: Mon, 9 Mar 2026 20:05:48 +0100
Subject: [PATCH] Perf: Polars-Import lazy gemacht (nur bei DB-Nutzung laden)
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Polars wird nicht mehr beim App-Start importiert, sondern erst wenn
eine Datenbankabfrage tatsächlich ausgeführt wird. Beschleunigt den
Kaltstart der Anwendung.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 src/ui/PostgreSqlConfigDialog.py | 9 ++++-----
 src/ui/mixins/database.py        | 3 ++-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/ui/PostgreSqlConfigDialog.py b/src/ui/PostgreSqlConfigDialog.py
index ad0b458..132c69f 100644
--- a/src/ui/PostgreSqlConfigDialog.py
+++ b/src/ui/PostgreSqlConfigDialog.py
@@ -3,21 +3,20 @@ from PySide6.QtCore import QThread, Signal, Qt
 
 from ui.PostgreSqlConfigDialog_ui import Ui_PostgreSqlConfigDialog
 
-import polars as pl
-
 
 class DatabaseTestThread(QThread):
     """Thread für den Datenbankverbindungstest."""
-    
+
     # Signale für die Kommunikation mit dem UI-Thread
     test_completed = Signal(bool, str)  # success, message
-    
+
     def __init__(self, connection_data):
         super().__init__()
         self.connection_data = connection_data
-    
+
     def run(self):
         """Führt den Datenbanktest in einem separaten Thread aus."""
+        import polars as pl
         try:
             timeout = self.connection_data.get("timeout", 10)
             uri = (
diff --git a/src/ui/mixins/database.py b/src/ui/mixins/database.py
index 14255ee..7d4e620 100644
--- a/src/ui/mixins/database.py
+++ b/src/ui/mixins/database.py
@@ -10,7 +10,6 @@ import time
 import logging
 from pathlib import Path
 
-import polars as pl
 from PySide6.QtCore import QThread, Signal, Qt
 from PySide6.QtWidgets import QMessageBox, QProgressDialog
 
@@ -31,6 +30,7 @@ class DatabaseQueryThread(QThread):
         self.connection_string = connection_string
 
     def run(self):
+        import polars as pl
         try:
             df = pl.read_database_uri(self.sql_query, self.connection_string, engine="connectorx").sort(
                 ["reporttyp_bez", "report_bez", "repfile_bez"]
@@ -208,6 +208,7 @@ class DatabaseMixin:
         Returns:
             list[TreeNode]: Liste der erstellten Root-Nodes
         """
+        import polars as pl
         try:
             start_time = time.time()