Commit 7af48cd7 authored by Shane Hathaway's avatar Shane Hathaway

Improved documentation of the refresh-related functionality.

- Renamed updateCodeTimestamp() to resetCaches().

- Added a test of resetCaches().

- Removed a spurious comment about chaining connections together.
parent 00df8ddb
......@@ -13,7 +13,7 @@
##############################################################################
"""Database connection support
$Id: Connection.py,v 1.103 2003/12/08 21:12:25 jeremy Exp $"""
$Id: Connection.py,v 1.104 2003/12/10 20:02:15 shane Exp $"""
import sys
import threading
......@@ -33,16 +33,20 @@ from ZODB.utils import oid_repr, z64
from ZODB.serialize \
import ObjectWriter, getClassMetadata, ConnectionObjectReader
global_code_timestamp = 0
global_reset_counter = 0
def updateCodeTimestamp():
"""Called after changes are made to persistence-based classes.
def resetCaches():
"""Causes all connection caches to be reset as connections are reopened.
Causes all connection caches to be re-created as the connections are
reopened.
Zope's refresh feature uses this. When you reload Python modules,
instances of classes continue to use the old class definitions.
To use the new code immediately, the refresh feature asks ZODB to
clear caches by calling resetCaches(). When the instances are
loaded by subsequent connections, they will use the new class
definitions.
"""
global global_code_timestamp
global_code_timestamp = time()
global global_reset_counter
global_reset_counter += 1
class Connection(ExportImport, object):
"""Object managers for individual object space.
......@@ -55,12 +59,9 @@ class Connection(ExportImport, object):
_tmp=None
_debug_info=()
_opened=None
_code_timestamp = 0
_reset_counter = 0
_transaction = None
# Experimental. Other connections can register to be closed
# when we close by putting something here.
def __init__(self, version='', cache_size=400,
cache_deactivate_after=60):
"""Create a new Connection"""
......@@ -76,7 +77,7 @@ class Connection(ExportImport, object):
self._cache.cache_drain_resistance = 100
self._incrgc = self.cacheGC = cache.incrgc
self._committed = []
self._code_timestamp = global_code_timestamp
self._reset_counter = global_reset_counter
self._load_count = 0 # Number of objects unghosted
self._store_count = 0 # Number of objects stored
......@@ -161,7 +162,7 @@ class Connection(ExportImport, object):
self._storage = odb._storage
self._sortKey = odb._storage.sortKey
self.new_oid = odb._storage.new_oid
if self._code_timestamp != global_code_timestamp:
if self._reset_counter != global_reset_counter:
# New code is in place. Start a new cache.
self._resetCache()
else:
......@@ -173,8 +174,11 @@ class Connection(ExportImport, object):
return self
def _resetCache(self):
"""Creates a new cache, discarding the old."""
self._code_timestamp = global_code_timestamp
"""Creates a new cache, discarding the old.
See the docstring for the resetCaches() function.
"""
self._reset_counter = global_reset_counter
self._invalidated.clear()
cache_size = self._cache.cache_size
self._cache = cache = PickleCache(self, cache_size)
......
......@@ -139,6 +139,9 @@ class ZODBTests(unittest.TestCase):
def checkResetCache(self):
# The cache size after a reset should be 0 and the GC attributes
# ought to be linked to it rather than the old cache.
# Note that _resetCache is not a public API, but the
# resetCaches() function is, and resetCaches() causes
# _resetCache() to be called.
self.populate()
conn = self._db.open()
conn.root()
......@@ -148,6 +151,19 @@ class ZODBTests(unittest.TestCase):
self.assert_(conn._incrgc == conn._cache.incrgc)
self.assert_(conn.cacheGC == conn._cache.incrgc)
def checkResetCachesAPI(self):
# Checks the resetCaches() API.
# (resetCaches used to be called updateCodeTimestamp.)
self.populate()
conn = self._db.open()
conn.root()
self.assert_(len(conn._cache) > 0) # Precondition
ZODB.Connection.resetCaches()
conn.close()
self.assert_(len(conn._cache) > 0) # Still not flushed
conn._setDB(self._db) # simulate the connection being reopened
self.assertEqual(len(conn._cache), 0)
def checkLocalTransactions(self):
# Test of transactions that apply to only the connection,
# not the thread.
......@@ -282,3 +298,7 @@ class ZODBTests(unittest.TestCase):
def test_suite():
return unittest.makeSuite(ZODBTests, 'check')
if __name__ == "__main__":
unittest.main(defaultTest="test_suite")
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