diff --git a/yum/__init__.py b/yum/__init__.py

index 6378cdc..cc57e98 100644

--- a/yum/__init__.py

+++ b/yum/__init__.py

@@ -427,6 +427,9 @@ class YumBase(depsolve.Depsolve):

     def closeRpmDB(self):

         """closes down the instances of the rpmdb we have wangling around"""

+        if self._rpmdb is not None:

+            self._rpmdb.ts = None

+            self._rpmdb.dropCachedData()

         self._rpmdb = None

         self._ts = None

         self._tsInfo = None

@@ -1008,6 +1011,7 @@ class YumBase(depsolve.Depsolve):

         # for any kind of install add from_repo to the yumdb, and the cmdline

         # and the install reason

+        self.rpmdb.dropCachedData()

         for txmbr in self.tsInfo:

             if txmbr.output_state in TS_INSTALL_STATES:

                 if not self.rpmdb.contains(po=txmbr.po):

@@ -1037,7 +1041,7 @@ class YumBase(depsolve.Depsolve):

             else:

                 self.verbose_logger.log(logginglevels.DEBUG_2, 'What is this? %s' % txmbr.po)

-

+        self.rpmdb.dropCachedData()

     def costExcludePackages(self):

         """exclude packages if they have an identical package in another repo

diff --git a/yum/rpmsack.py b/yum/rpmsack.py

index 5189b18..8556e9a 100644

--- a/yum/rpmsack.py

+++ b/yum/rpmsack.py

@@ -140,7 +140,10 @@ class RPMDBPackageSack(PackageSackBase):

         self._simple_pkgtup_list = []

         self._get_pro_cache = {}

         self._get_req_cache = {}

-        misc.unshare_data()

+        #  We can be called on python shutdown (due to yb.__del__), at which

+        # point other modules might not be available.

+        if misc is not None:

+            misc.unshare_data()

         self._cache = {

             'provides' : { },

             'requires' : { },