Commit 2c105365 authored by Thomas Lotze's avatar Thomas Lotze

- Fixed bug in ClientCache that occurred with objects larger than the total

  cache size.
parent 668dc2af
......@@ -10,7 +10,7 @@ New Features
- Versions are no-longer supported.
- ZEO cache files can be larger than 4G. Note that lder ZEO cache
- ZEO cache files can be larger than 4G. Note that older ZEO cache
files are not supported.
- Document conflict resolution (see ZODB/ConflictResolution.txt).
......@@ -62,3 +62,6 @@ Bugs Fixed
deal with garbage files
- Fixed bug in which MVCC would not work for blobs.
- Fixed bug in ClientCache that occurred with objects larger than the total
cache size.
......@@ -234,6 +234,8 @@ class ClientCache(object):
"already have current data for oid")
else:
return
if not self.fc.add(o):
return # too large
self.current[oid] = start_tid
self._trace(0x52, oid, start_tid, dlen=len(data))
else:
......@@ -241,9 +243,10 @@ class ClientCache(object):
p = start_tid, end_tid
if p in L:
return # duplicate store
if not self.fc.add(o):
return # too large
bisect.insort_left(L, p)
self._trace(0x54, oid, start_tid, end_tid, dlen=len(data))
self.fc.add(o)
##
# Remove all knowledge of noncurrent revisions of oid, both in
......@@ -883,7 +886,8 @@ class FileCache(object):
##
# Add Object object to the cache. This may evict existing objects, to
# make room (and almost certainly will, in steady state once the cache
# is first full). The object must not already be in the cache.
# is first full). The object must not already be in the cache. If the
# object is too large for the cache, False is returned, otherwise True.
def add(self, object):
size = OBJECT_HEADER_SIZE + object.size
# A number of cache simulation experiments all concluded that the
......@@ -891,7 +895,7 @@ class FileCache(object):
# objects simply weren't cached. For now, we ignore the request
# only if the entire cache file is too small to hold the object.
if size > self.maxsize - ZEC4_HEADER_SIZE:
return
return False
assert object.key not in self.key2entry
assert len(object.key[0]) == 8
......@@ -902,6 +906,7 @@ class FileCache(object):
available = self._makeroom(size)
self._writeobj(object, available)
return True
##
# Return Object for key, or None if not in cache.
......
......@@ -52,6 +52,7 @@ Initially the object is not in the cache:
We can add it to the cache:
>>> fc.add(obj1_1)
True
And now it's in the cache:
......@@ -146,6 +147,7 @@ Case 1: Allocating a new block that fits after the last used one
>>> obj2_1 = Object(key=(oid(2), tid(1)), data='******',
... start_tid=tid(1), end_tid=None)
>>> fc.add(obj2_1)
True
The new block fits exactly in the remaining 47 bytes (41 bytes header + 6
bytes payload) so the beginning of the data is the same except for the last 47
......@@ -171,6 +173,7 @@ Case 2: Allocating a block that wraps around and frees *exactly* one block
>>> obj3_1 = Object(key=(oid(3), tid(1)), data='@'*100,
... start_tid=tid(1), end_tid=None)
>>> fc.add(obj3_1)
True
>>> hexprint(fc.f)
00000000 5a 45 43 34 00 00 00 00 00 00 00 00 61 00 00 00 |ZEC4........a...|
......@@ -192,6 +195,7 @@ Case 3: Allocating a block that requires 1 byte less than the next block
>>> obj4_1 = Object(key=(oid(4), tid(1)), data='~~~~~',
... start_tid=tid(1), end_tid=None)
>>> fc.add(obj4_1)
True
>>> hexprint(fc.f)
00000000 5a 45 43 34 00 00 00 00 00 00 00 00 61 00 00 00 |ZEC4........a...|
......@@ -213,6 +217,7 @@ Case 4: Allocating a block that requires 2 bytes less than the next block
>>> obj4_1 = Object(key=(oid(5), tid(1)), data='^'*98,
... start_tid=tid(1), end_tid=None)
>>> fc.add(obj4_1)
True
>>> hexprint(fc.f)
00000000 5a 45 43 34 00 00 00 00 00 00 00 00 61 00 00 00 |ZEC4........a...|
......@@ -239,6 +244,7 @@ it.
>>> obj4_1 = Object(key=(oid(6), tid(1)), data='+'*95,
... start_tid=tid(1), end_tid=None)
>>> fc.add(obj4_1)
True
>>> hexprint(fc.f)
00000000 5a 45 43 34 00 00 00 00 00 00 00 00 61 00 00 00 |ZEC4........a...|
......@@ -264,6 +270,7 @@ file.
>>> obj4_1 = Object(key=(oid(7), tid(1)), data='-'*89,
... start_tid=tid(1), end_tid=None)
>>> fc.add(obj4_1)
True
>>> hexprint(fc.f)
00000000 5a 45 43 34 00 00 00 00 00 00 00 00 61 00 00 00 |ZEC4........a...|
......@@ -287,6 +294,7 @@ Again, we replace the block at the beginning of the cache.
>>> obj4_1 = Object(key=(oid(8), tid(1)), data='='*80,
... start_tid=tid(1), end_tid=None)
>>> fc.add(obj4_1)
True
>>> hexprint(fc.f)
00000000 5a 45 43 34 00 00 00 00 00 00 00 00 61 00 00 00 |ZEC4........a...|
......
......@@ -241,6 +241,36 @@ class CacheTests(unittest.TestCase):
eq(copy.current, self.cache.current)
eq(copy.noncurrent, self.cache.noncurrent)
def testCurrentObjectLargerThanCache(self):
if self.cache.path:
os.remove(self.cache.path)
self.cache = ZEO.cache.ClientCache(size=50)
self.cache.open()
# We store an object that is a bit larger than the cache can handle.
self.cache.store(n1, n2, None, "x"*64)
# We can see that it was not stored.
self.assertEquals(None, self.cache.load(n1))
# If an object cannot be stored in the cache, it must not be
# recorded as current.
self.assert_(n1 not in self.cache.current)
# Regression test: invalidation must still work.
self.cache.invalidate(n1, n2)
def testOldObjectLargerThanCache(self):
if self.cache.path:
os.remove(self.cache.path)
self.cache = ZEO.cache.ClientCache(size=50)
self.cache.open()
# We store an object that is a bit larger than the cache can handle.
self.cache.store(n1, n2, n3, "x"*64)
# We can see that it was not stored.
self.assertEquals(None, self.cache.load(n1))
# If an object cannot be stored in the cache, it must not be
# recorded as non-current.
self.assert_((n2, n3) not in self.cache.noncurrent[n1])
def test_suite():
suite = unittest.TestSuite()
......
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