[dak/master] Provide a way to set Pg's work_mem from dak.

[Torsten Werner <twerner@debian.org>]

Signed-off-by: Torsten Werner <twerner@debian.org>
---
 daklib/contents.py |    4 ++--
 daklib/dbconn.py   |   13 +++++++++++--
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/daklib/contents.py b/daklib/contents.py
index f3077aa..449fb88 100755
--- a/daklib/contents.py
+++ b/daklib/contents.py
@@ -285,7 +285,7 @@ def binary_helper(suite_id, arch_id, overridetype_id, component_id = None):
     This function is called in a new subprocess and multiprocessing wants a top
     level function.
     '''
-    session = DBConn().session()
+    session = DBConn().session(work_mem = 1000)
     suite = Suite.get(suite_id, session)
     architecture = Architecture.get(arch_id, session)
     overridetype = OverrideType.get(overridetype_id, session)
@@ -304,7 +304,7 @@ def source_helper(suite_id, component_id):
     This function is called in a new subprocess and multiprocessing wants a top
     level function.
     '''
-    session = DBConn().session()
+    session = DBConn().session(work_mem = 1000)
     suite = Suite.get(suite_id, session)
     component = Component.get(component_id, session)
     log_message = [suite.suite_name, 'source', component.component_name]
diff --git a/daklib/dbconn.py b/daklib/dbconn.py
index ae5a9e0..9c25f67 100755
--- a/daklib/dbconn.py
+++ b/daklib/dbconn.py
@@ -3591,12 +3591,21 @@ class DBConn(object):
         self.__setupmappers()
         self.pid = os.getpid()
 
-    def session(self):
+    def session(self, work_mem = 0):
+        '''
+        Returns a new session object. If a work_mem parameter is provided a new
+        transaction is started and the work_mem parameter is set for this
+        transaction. The work_mem parameter is measured in MB. A default value
+        will be used if the parameter is not set.
+        '''
         # reinitialize DBConn in new processes
         if self.pid != os.getpid():
             clear_mappers()
             self.__createconn()
-        return self.db_smaker()
+        session = self.db_smaker()
+        if work_mem > 0:
+            session.execute("SET LOCAL work_mem TO '%d MB'" % work_mem)
+        return session
 
 __all__.append('DBConn')
 
-- 
1.7.2.5