From: Zac Medico <zmedico@gentoo.org>
Date: Wed, 11 Mar 2009 06:01:59 +0000 (-0000)
Subject: When loading vdb_metadata.pickle inside vardbapi._aux_cache_init(), in
X-Git-Tag: v2.1.6.8~149
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=09621d445e87c102869e5c97898fda55c217d643;p=portage.git

When loading vdb_metadata.pickle inside vardbapi._aux_cache_init(), in
order to avoid an extreme performance issue, disable buffering when opening
the file under python-3.0. Unfortunately, performance is still poor relative
to python-2.x, but buffering makes it much worse. (trunk r12665)

svn path=/main/branches/2.1.6/; revision=12928
---

diff --git a/pym/portage/dbapi/vartree.py b/pym/portage/dbapi/vartree.py
index 3c8ece366..f65afb6bd 100644
--- a/pym/portage/dbapi/vartree.py
+++ b/pym/portage/dbapi/vartree.py
@@ -35,6 +35,7 @@ from portage.cache.mappings import slot_dict_class
 import os, re, shutil, stat, errno, copy, subprocess
 import logging
 import shlex
+import sys
 from itertools import izip
 
 try:
@@ -389,8 +390,15 @@ class vardbapi(dbapi):
 
 	def _aux_cache_init(self):
 		aux_cache = None
+		open_kwargs = {}
+		if sys.hexversion >= 0x3000000:
+			# Buffered io triggers extreme performance issues in
+			# Unpickler.load() (problem observed with python-3.0.1).
+			# Unfortunately, performance is still poor relative to
+			# python-2.x, but buffering makes it much worse.
+			open_kwargs["buffering"] = 0
 		try:
-			f = open(self._aux_cache_filename, 'rb')
+			f = open(self._aux_cache_filename, mode='rb', **open_kwargs)
 			mypickle = pickle.Unpickler(f)
 			aux_cache = mypickle.load()
 			f.close()