原文：http://gentoo-wiki.com/TIP_speed_up_portage_with_cdb

注意: この方法は ~x86 unstable にある portage-2.1 だと利用できなくなっています。

cdbでPortageを高速化 ↑

• cdbでPortageを高速化
  • はじめに
  • 警告
  • 必要なもの
  • Portageの設定
    • 新規モジュールの作成
    • Portageがこれを使うようにする
    • 最終段階
  • 最後に

はじめに ↑

このtipでは、syncの後や依存関係の計算のPortageの速度を劇的に増加させる方法を教えます。この手法は、ただのファイルの束をmetadataに保存する代わりに、データベースを使用します。これにはcdbモジュールが必要です。原文(原文の原文)はフォーラムで見ることができます。

また、bugzillaにはebuildがあります。

警告 ↑

The method this tip uses to plugin a new module to portage is fine- portage devs added it to portage explicitly for purposes like this. That said, using a third party plugin with portage means you have to deal with the bugs- for example, if you unmerge python-cdb, you need to remember to remove the custom /etc/portage/modules setting.

Beyond that, an upcoming cache backport to 2.0.x from the >=2.1 line of portage will break this module. This should occur sometime around >=2.0.54. However, instructions are below which will repair the problem.

必要なもの ↑

多くは必要ありません。テキストエディタと、cdbモジュールだけです。ではemergeしましょう。

 emerge dev-python/python-cdb

Portageの設定 ↑

これを動作させるには、2つのファイルを作成/編集する必要があります。

新規モジュールの作成 ↑

We first need to create a new file, telling portage how to work with cdb. So create the new file /usr/lib/portage/pym/portage_db_cdb.py and put the following in it:

File: /usr/lib/portage/pym/portage_db_cdb.py

 # Copyright 2004, 2005 Tobias Bell <[email protected]>
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation; either version 2 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 
 import portage_db_template
 import os
 import os.path
 import cPickle
 import cdb
 
 
 class _data(object):
 
     def __init__(self, path, category, uid, gid):
         self.path = path
         self.category = category
         self.uid = uid
         self.gid = gid
         self.addList = {}
         self.delList = []
         self.modified = False
         self.cdbName = os.path.normpath(os.path.join(
             self.path, self.category) + ".cdb")
         self.cdbObject = None
 
     def __del__(self):
         if self.modified:
             self.realSync()
 
         self.closeCDB()
 
     def realSync(self):
         if self.modified:
             self.modified = False
             newDB = cdb.cdbmake(self.cdbName, self.cdbName + ".tmp")
            
             for key, value in iter(self.cdbObject.each, None):
                 if key in self.delList:
                     if key in self.addList:
                         newDB.add(key, cPickle.dumps(self.addList[key], cPickle.HIGHEST_PROTOCOL))
                         del self.addList[key]
                 elif key in self.addList:                   
                     newDB.add(key, cPickle.dumps(self.addList[key], cPickle.HIGHEST_PROTOCOL))
                     del self.addList[key]
                 else:
                     newDB.add(key, value)
 
 
             self.closeCDB()
 
             for key, value in self.addList.iteritems():
                 newDB.add(key, cPickle.dumps(value, cPickle.HIGHEST_PROTOCOL))
 
             newDB.finish()
             del newDB
 
             self.addList = {}
             self.delList = []
 
             self.openCDB()
 
     def openCDB(self):
         prevmask = os.umask(0)
 
         if not os.path.exists(self.path):
             os.makedirs(self.path, 02775)
             os.chown(self.path, self.uid, self.gid)
 
         if not os.path.isfile(self.cdbName):
             maker = cdb.cdbmake(self.cdbName, self.cdbName + ".tmp")
             maker.finish()
             del maker
             os.chown(self.cdbName, self.uid, self.gid)
             os.chmod(self.cdbName, 0664)
 
         os.umask(prevmask)
 
         self.cdbObject = cdb.init(self.cdbName)
 
     def closeCDB(self):
         if self.cdbObject:
             self.cdbObject = None
 
 
 class _dummyData:
     cdbName = ""
 
     def realSync():
         pass
     realSync = staticmethod(realSync)
 
 
 _cacheSize = 4
 _cache = [_dummyData()] * _cacheSize
 
 
 class database(portage_db_template.database):   
 
     def module_init(self):
         self.data = _data(self.path, self.category, self.uid, self.gid)
 
         for other in _cache:
             if other.cdbName == self.data.cdbName:
                 self.data = other
                 break
         else:
             self.data.openCDB()
             _cache.insert(0, self.data)           
             _cache.pop().realSync()
            
     def has_key(self, key):
         self.check_key(key)
         retVal = 0
 
         if self.data.cdbObject.get(key) is not None:
             retVal = 1
 
         if self.data.modified:
             if key in self.data.delList:
                 retVal = 0
             if key in self.data.addList:
                 retVal = 1
            
         return retVal
 
     def keys(self):
         myKeys = self.data.cdbObject.keys()
 
         if self.data.modified:
             for k in self.data.delList:
                 myKeys.remove(k)
             for k in self.data.addList.iterkeys():
                 if k not in myKeys:
                     myKeys.append(k)
                    
         return myKeys
 
     def get_values(self, key):
         values = None
        
         if self.has_key(key):
             if key in self.data.addList:
                 values = self.data.addList[key]
             else:
                 values = cPickle.loads(self.data.cdbObject.get(key))
 
         return values
    
     def set_values(self, key, val):
         self.check_key(key)
         self.data.modified = True
         self.data.addList[key] = val
 
     def del_key(self, key):
         retVal = 0
        
         if self.has_key(key):
             self.data.modified = True
             retVal = 1
             if key in self.data.addList:
                 del self.data.addList[key]
             else:
                 self.data.delList.append(key)
 
         return retVal
                    
     def sync(self):
         pass
    
     def close(self):
         pass
 
 
 if __name__ == "__main__":
     import portage
     uid = os.getuid()
     gid = os.getgid()
     portage_db_template.test_database(database,"/tmp", "sys-apps", portage.auxdbkeys, uid, gid) 

Portageがこれを使うようにする ↑

After setting that up, we need to tell portage to use our new database. So create the file /etc/portage/modules (if its not already there) and put the following in it:

File: /etc/portage/modules

 portdbapi.auxdbmodule = portage_db_cdb.database
 eclass_cache.dbmodule = portage_db_cdb.database 

最終段階 ↑

必要なことはPortageのキャッシュを再構築することだけです。

 emerge metadata

最後に ↑

• New updates to portage will be much faster, and if you use emerge --searchdesc then you'll definitely notice a speedup as well.
• If you want to turn this off, just comment out the two lines we added in /etc/portage/modules.
• Will this work with a /usr/portage that is shared across multiple servers? If so, does the module and cdb need to be installed on every one or...?
• According to DirtyEpic? on the Gentoo Forums, upgrading to python-2.4 will break portage. Comment out your /etc/portage/modules file, and remerge portage and python-cdb to fix it. [you can also just leave it and run python-updater, which you should be doing after each python upgrade]