From: Daniele Varrazzo <daniele.varrazzo@gmail.com>
Date: Tue, 19 Sep 2023 20:38:03 +0000 (+0200)
Subject: perf(windows): don't use wait_c.
X-Git-Tag: pool-3.1.8~10
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ca41e834ec3aee184a297646776dbf093adaffdf;p=thirdparty%2Fpsycopg.git

perf(windows): don't use wait_c.

The function was reported to use excessive CPU. Need to investigate,
however, for the moment, suspend its usage on Windows.

See #645.
---

diff --git a/docs/news.rst b/docs/news.rst
index 63290f460..978cf3860 100644
--- a/docs/news.rst
+++ b/docs/news.rst
@@ -17,6 +17,7 @@ Psycopg 3.1.11 (unreleased)
   usage (:ticket:`#628`).
 - Fix integer overflow in C/binary extension with OID > 2^31 (:ticket:`#630`).
 - Fix loading of intervals with days and months or years (:ticket:`#643`).
+- Work around excessive CPU usage on Windows (reported in :ticket:`#645`).
 - Fix building on Solaris and derivatives (:ticket:`#632`).
 - Fix possible lack of critical section guard in async
   `~AsyncCursor.executemany()`.
diff --git a/psycopg/psycopg/waiting.py b/psycopg/psycopg/waiting.py
index 2c4a10fd1..80827152c 100644
--- a/psycopg/psycopg/waiting.py
+++ b/psycopg/psycopg/waiting.py
@@ -10,6 +10,7 @@ These functions are designed to consume the generators returned by the
 
 
 import os
+import sys
 import select
 import selectors
 from typing import Dict, Optional
@@ -310,7 +311,10 @@ if "PSYCOPG_WAIT_FUNC" in os.environ:
         )
     wait = globals()[fname]
 
-elif _psycopg:
+# On Windows, for the moment, avoid using wait_c, because it was reported to
+# use excessive CPU (see #645).
+# TODO: investigate why.
+elif _psycopg and sys.platform != "win32":
     wait = wait_c
 
 elif selectors.DefaultSelector is getattr(selectors, "SelectSelector", None):