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Commit 671a5fb8 authored by Jim Fulton's avatar Jim Fulton Committed by GitHub
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Merge pull request #48 from zopefoundation/prefetch 

Optimizations, featuring prefetch
parents 3c525909 09d8df62
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Showing with 287 additions and 284 deletions
src/ZEO/ClientStorage.py
View file @ 671a5fb8
......@@ -504,8 +504,15 @@ class ClientStorage(ZODB.ConflictResolution.ConflictResolvingStorage):
return result[:2]
def loadBefore(self, oid, tid):
result = self._cache.loadBefore(oid, tid)
if result:
return result
return self._server.load_before(oid, tid)
def prefetch(self, oids, tid):
self._server.prefetch(oids, tid)
def new_oid(self):
"""Storage API: return a new object identifier.
"""
......
src/ZEO/asyncio/client.py
View file @ 671a5fb8
......@@ -8,6 +8,7 @@ else:
from ZEO.Exceptions import ClientDisconnected
from ZODB.ConflictResolution import ResolvedSerial
import concurrent.futures
import functools
import logging
import random
import threading
......@@ -27,6 +28,37 @@ Fallback = object()
local_random = random.Random() # use separate generator to facilitate tests
def future_generator(func):
"""Decorates a generator that generates futures
"""
@functools.wraps(func)
def call_generator(*args, **kw):
gen = func(*args, **kw)
try:
f = next(gen)
except StopIteration:
gen.close()
else:
def store(gen, future):
@future.add_done_callback
def _(future):
try:
try:
result = future.result()
except Exception as exc:
f = gen.throw(exc)
else:
f = gen.send(result)
except StopIteration:
gen.close()
else:
store(gen, f)
store(gen, f)
return call_generator
class Protocol(base.Protocol):
"""asyncio low-level ZEO client interface
"""
......@@ -127,15 +159,9 @@ class Protocol(base.Protocol):
self.closed = True
self.client.disconnected(self)
@future_generator
def finish_connect(self, protocol_version):
# We use a promise model rather than coroutines here because
# for the most part, this class is reactive and coroutines
# aren't a good model of it's activities. During
# initialization, however, we use promises to provide an
# imperative flow.
# The promise(/future) implementation we use differs from
# The future implementation we use differs from
# asyncio.Future in that callbacks are called immediately,
# rather than using the loops call_soon. We want to avoid a
# race between invalidations and cache initialization. In
......@@ -150,56 +176,29 @@ class Protocol(base.Protocol):
self.client.register_failed(
self, ZEO.Exceptions.ProtocolError(protocol_version))
return
self._write(self.protocol_version)
register = self.promise(
try:
try:
server_tid = yield self.fut(
'register', self.storage_key,
self.read_only if self.read_only is not Fallback else False,
)
if self.read_only is not Fallback:
# Get lastTransaction in flight right away to make
# successful connection quicker, but only if we're not
# doing read-only fallback. If we might need to retry, we
# can't send lastTransaction because if the registration
# fails, it will be seen as an invalid message and the
# connection will close. :( It would be a lot better of
# registere returned the last transaction (and info while
# it's at it).
lastTransaction = self.promise('lastTransaction')
else:
lastTransaction = None # to make python happy
@register
def registered(_):
except ZODB.POSException.ReadOnlyError:
if self.read_only is Fallback:
self.read_only = False
r_lastTransaction = self.promise('lastTransaction')
else:
r_lastTransaction = lastTransaction
self.client.registered(self, r_lastTransaction)
@register.catch
def register_failed(exc):
if (isinstance(exc, ZODB.POSException.ReadOnlyError) and
self.read_only is Fallback):
# We tried a write connection, degrade to a read-only one
self.read_only = True
logger.info("%s write connection failed. Trying read-only",
self)
register = self.promise('register', self.storage_key, True)
# get lastTransaction in flight.
lastTransaction = self.promise('lastTransaction')
@register
def registered(_):
self.client.registered(self, lastTransaction)
@register.catch
def register_failed(exc):
self.client.register_failed(self, exc)
server_tid = yield self.fut(
'register', self.storage_key, True)
else:
raise
else:
if self.read_only is Fallback:
self.read_only = False
except Exception as exc:
self.client.register_failed(self, exc)
else:
self.client.registered(self, server_tid)
exception_type_type = type(Exception)
def message_received(self, data):
......@@ -237,8 +236,19 @@ class Protocol(base.Protocol):
self._write(self.encode(self.message_id, False, method, args))
return future
def promise(self, method, *args):
return self.call(Promise(), method, args)
def fut(self, method, *args):
return self.call(Fut(), method, args)
def load_before(self, oid, tid):
# Special-case loadBefore, so we collapse outstanding requests
message_id = (oid, tid)
future = self.futures.get(message_id)
if future is None:
future = asyncio.Future(loop=self.loop)
self.futures[message_id] = future
self._write(
self.encode(message_id, False, 'loadBefore', (oid, tid)))
return future
# Methods called by the server.
# WARNING WARNING we can't call methods that call back to us
......@@ -362,18 +372,18 @@ class Client(object):
for addr in self.addrs
]
def registered(self, protocol, last_transaction_promise):
def registered(self, protocol, server_tid):
if self.protocol is None:
self.protocol = protocol
if not (self.read_only is Fallback and protocol.read_only):
# We're happy with this protocol. Tell the others to
# stop trying.
self._clear_protocols(protocol)
self.verify(last_transaction_promise)
self.verify(server_tid)
elif (self.read_only is Fallback and not protocol.read_only and
self.protocol.read_only):
self.upgrade(protocol)
self.verify(last_transaction_promise)
self.verify(server_tid)
else:
protocol.close() # too late, we went home with another
......@@ -391,11 +401,14 @@ class Client(object):
self.try_connecting)
verify_result = None # for tests
def verify(self, last_transaction_promise):
@future_generator
def verify(self, server_tid):
protocol = self.protocol
if server_tid is None:
server_tid = yield protocol.fut('lastTransaction')
@last_transaction_promise
def finish_verify(server_tid):
try:
cache = self.cache
if cache:
cache_tid = cache.getLastTid()
......@@ -404,7 +417,6 @@ class Client(object):
logger.error("Non-empty cache w/o tid -- clearing")
cache.clear()
self.client.invalidateCache()
self.finished_verify(server_tid)
elif cache_tid > server_tid:
self.verify_result = "Cache newer than server"
logger.critical(
......@@ -413,17 +425,14 @@ class Client(object):
server_tid, cache_tid, protocol)
elif cache_tid == server_tid:
self.verify_result = "Cache up to date"
self.finished_verify(server_tid)
else:
@protocol.promise('getInvalidations', cache_tid)
def verify_invalidations(vdata):
vdata = yield protocol.fut('getInvalidations', cache_tid)
if vdata:
self.verify_result = "quick verification"
tid, oids = vdata
server_tid, oids = vdata
for oid in oids:
cache.invalidate(oid, None)
self.client.invalidateTransaction(tid, oids)
return tid
self.client.invalidateTransaction(server_tid, oids)
else:
# cache is too old
self.verify_result = "cache too old, clearing"
......@@ -438,37 +447,33 @@ class Client(object):
)
self.cache.clear()
self.client.invalidateCache()
return server_tid
verify_invalidations(
self.finished_verify,
self.connected.set_exception,
)
else:
self.verify_result = "empty cache"
self.finished_verify(server_tid)
@finish_verify.catch
def verify_failed(exc):
except Exception as exc:
del self.protocol
self.register_failed(protocol, exc)
def finished_verify(self, server_tid):
else:
# The cache is validated and the last tid we got from the server.
# Set ready so we apply any invalidations that follow.
# We've been ignoring them up to this point.
self.cache.setLastTid(server_tid)
self.ready = True
@self.protocol.promise('get_info')
def got_info(info):
self.client.notify_connected(self, info)
self.connected.set_result(None)
try:
info = yield protocol.fut('get_info')
except Exception as exc:
# This is weird. We were connected and verified our cache, but
# Now we errored getting info.
@got_info.catch
def failed_info(exc):
# XXX Need a test fpr this. The lone before is what we
# had, but it's wrong.
self.register_failed(self, exc)
else:
self.client.notify_connected(self, info)
self.connected.set_result(None)
def get_peername(self):
return self.protocol.get_peername()
......@@ -514,27 +519,49 @@ class Client(object):
# Special methods because they update the cache.
@future_generator
def load_before_threadsafe(self, future, oid, tid):
data = self.cache.loadBefore(oid, tid)
if data is not None:
future.set_result(data)
elif self.ready:
@self.protocol.promise('loadBefore', oid, tid)
def load_before(data):
try:
data = yield self.protocol.load_before(oid, tid)
except Exception as exc:
future.set_exception(exc)
else:
future.set_result(data)
if data:
data, start, end = data
self.cache.store(oid, start, end, data)
load_before.catch(future.set_exception)
else:
self._when_ready(self.load_before_threadsafe, future, oid, tid)
@future_generator
def _prefetch(self, oid, tid):
try:
data = yield self.protocol.load_before(oid, tid)
if data:
data, start, end = data
self.cache.store(oid, start, end, data)
except Exception:
logger.exception("prefetch %r %r" % (oid, tid))
def prefetch(self, future, oids, tid):
if self.ready:
for oid in oids:
if self.cache.loadBefore(oid, tid) is None:
self._prefetch(oid, tid)
future.set_result(None)
else:
future.set_exception(ClientDisconnected())
@future_generator
def tpc_finish_threadsafe(self, future, tid, updates, f):
if self.ready:
@self.protocol.promise('tpc_finish', tid)
def committed(tid):
try:
tid = yield self.protocol.fut('tpc_finish', tid)
cache = self.cache
for oid, data, resolved in updates:
cache.invalidate(oid, tid)
......@@ -552,8 +579,6 @@ class Client(object):
else:
f(tid)
future.set_result(tid)
committed.catch(future.set_exception)
else:
future.set_exception(ClientDisconnected())
......@@ -648,6 +673,9 @@ class ClientRunner(object):
def async_iter(self, it):
return self.__call(self.client.call_async_iter_threadsafe, it)
def prefetch(self, oids, tid):
return self.__call(self.client.prefetch, oids, tid)
def load_before(self, oid, tid):
return self.__call(self.client.load_before_threadsafe, oid, tid)
......@@ -754,95 +782,24 @@ class ClientThread(ClientRunner):
if self.exception:
raise self.exception
class Promise(object):
"""Lightweight future with a partial promise API.
These are lighweight because they call callbacks synchronously
rather than through an event loop, and because they ony support
single callbacks.
class Fut(object):
"""Lightweight future that calls it's callback immediately rather than soon
"""
# Note that we can know that they are completed after callbacks
# are set up because they're used to make network requests.
# Requests are made by writing to a transport. Because we're used
# in a single-threaded protocol, we can't get a response and be
# completed if the callbacks are set in the same code that
# created the promise, which they are.
next = success_callback = error_callback = cancelled = None
def __call__(self, success_callback = None, error_callback = None):
"""Set the promises success and error handlers and beget a new promise
The promise returned provides for promise chaining, providing
a sane imperative flow. Let's call this the "next" promise.
Any results or exceptions generated by the promise or it's
callbacks are passed on to the next promise.
When the promise completes successfully, if a success callback
isn't set, then the next promise is completed with the
successfull result. If a success callback is provided, it's
called. If the call succeeds, and the result is a promise,
them the result is called with the next promise's set_result
and set_exception methods, chaining the result and next
promise. If the result isn't a promise, then the next promise
is completed with it by calling set_result. If the success
callback fails, then it's exception is passed to
next.set_exception.
If the promise completes with an error and the error callback
isn't set, then the exception is passed to the next promises
set_exception. If an error handler is provided, it's called
and if it doesn't error, then the original exception is passed
to the next promise's set_exception. If there error handler
errors, then that exception is passed to the next promise's
set_exception.
"""
self.next = self.__class__()
self.success_callback = success_callback
self.error_callback = error_callback
return self.next
def cancel(self):
self.set_exception(concurrent.futures.CancelledError)
def catch(self, error_callback):
self.error_callback = error_callback
def add_done_callback(self, cb):
self.cb = cb
exc = None
def set_exception(self, exc):
self._notify(None, exc)
self.exc = exc
self.cb(self)
def set_result(self, result):
self._notify(result, None)
self._result = result
self.cb(self)
def _notify(self, result, exc):
next = self.next
if exc is not None:
if self.error_callback is not None:
try:
result = self.error_callback(exc)
except Exception:
logger.exception("Exception handling error %s", exc)
if next is not None:
next.set_exception(exc)
else:
if next is not None:
next.set_result(result)
elif next is not None:
next.set_exception(exc)
else:
if self.success_callback is not None:
try:
result = self.success_callback(result)
except Exception as exc:
logger.exception("Exception in success callback")
if next is not None:
next.set_exception(exc)
else:
if next is not None:
if isinstance(result, Promise):
result(next.set_result, next.set_exception)
def result(self):
if self.exc:
raise self.exc
else:
next.set_result(result)
elif next is not None:
next.set_result(result)
return self._result
src/ZEO/asyncio/tests.py
View file @ 671a5fb8
......@@ -12,7 +12,6 @@ from ZODB.POSException import ReadOnlyError
import collections
import logging
import pdb
import struct
import unittest
......@@ -71,6 +70,12 @@ class Base(object):
class ClientTests(Base, setupstack.TestCase, ClientRunner):
maxDiff = None
def tearDown(self):
self.client.close()
super(ClientTests, self)
def start(self,
addrs=(('127.0.0.1', 8200), ), loop_addrs=None,
read_only=False,
......@@ -95,12 +100,9 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
if finish_start:
protocol.data_received(sized(b'Z3101'))
self.assertEqual(self.pop(2, False), b'Z3101')
self.assertEqual(self.pop(),
[(1, False, 'register', ('TEST', False)),
(2, False, 'lastTransaction', ()),
])
self.respond(1, None)
self.respond(2, 'a'*8)
self.pop(4)
self.assertEqual(self.pop(), (3, False, 'get_info', ()))
self.respond(3, dict(length=42))
......@@ -134,12 +136,9 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
# The client sends back a handshake, and registers the
# storage, and requests the last transaction.
self.assertEqual(self.pop(2, False), b'Z5')
self.assertEqual(self.pop(),
[(1, False, 'register', ('TEST', False)),
(2, False, 'lastTransaction', ()),
])
self.assertEqual(self.pop(), (1, False, 'register', ('TEST', False)))
# Actually, the client isn't connected until it initializes it's cache:
# The client isn't connected until it initializes it's cache:
self.assertFalse(client.connected.done() or transport.data)
# If we try to make calls while the client is *initially*
......@@ -162,9 +161,13 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
# The wrapper object (ClientStorage) hasn't been notified:
self.assertFalse(wrapper.notify_connected.called)
# Let's respond to those first 2 calls:
# Let's respond to the register call:
self.respond(1, None)
# The client requests the last transaction:
self.assertEqual(self.pop(), (2, False, 'lastTransaction', ()))
# We respond
self.respond(2, 'a'*8)
# After verification, the client requests info:
......@@ -191,9 +194,11 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
# Loading objects gets special handling to leverage the cache.
loaded = self.load_before(b'1'*8, m64)
# The data wasn't in the cache, so we make a server call:
self.assertEqual(self.pop(), (5, False, 'loadBefore', (b'1'*8, m64)))
self.respond(5, (b'data', b'a'*8, None))
# The data wasn't in the cache, so we made a server call:
self.assertEqual(self.pop(),
((b'1'*8, m64), False, 'loadBefore', (b'1'*8, m64)))
# Note load_before uses the oid as the message id.
self.respond((b'1'*8, m64), (b'data', b'a'*8, None))
self.assertEqual(loaded.result(), (b'data', b'a'*8, None))
# If we make another request, it will be satisfied from the cache:
......@@ -206,9 +211,16 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
# Now, if we try to load current again, we'll make a server request.
loaded = self.load_before(b'1'*8, m64)
self.assertEqual(self.pop(), (6, False, 'loadBefore', (b'1'*8, m64)))
self.respond(6, (b'data2', b'b'*8, None))
# Note that if we make another request for the same object,
# the requests will be collapsed:
loaded2 = self.load_before(b'1'*8, m64)
self.assertEqual(self.pop(),
((b'1'*8, m64), False, 'loadBefore', (b'1'*8, m64)))
self.respond((b'1'*8, m64), (b'data2', b'b'*8, None))
self.assertEqual(loaded.result(), (b'data2', b'b'*8, None))
self.assertEqual(loaded2.result(), (b'data2', b'b'*8, None))
# Loading non-current data may also be satisfied from cache
loaded = self.load_before(b'1'*8, b'b'*8)
......@@ -219,9 +231,10 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
self.assertFalse(transport.data)
loaded = self.load_before(b'1'*8, b'_'*8)
self.assertEqual(self.pop(),
(7, False, 'loadBefore', (b'1'*8, b'_'*8)))
self.respond(7, (b'data0', b'^'*8, b'_'*8))
self.assertEqual(
self.pop(),
((b'1'*8, b'_'*8), False, 'loadBefore', (b'1'*8, b'_'*8)))
self.respond((b'1'*8, b'_'*8), (b'data0', b'^'*8, b'_'*8))
self.assertEqual(loaded.result(), (b'data0', b'^'*8, b'_'*8))
# When committing transactions, we need to update the cache
......@@ -244,8 +257,8 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
cache.load(b'4'*8))
self.assertEqual(cache.load(b'1'*8), (b'data2', b'b'*8))
self.assertEqual(self.pop(),
(8, False, 'tpc_finish', (b'd'*8,)))
self.respond(8, b'e'*8)
(5, False, 'tpc_finish', (b'd'*8,)))
self.respond(5, b'e'*8)
self.assertEqual(committed.result(), b'e'*8)
self.assertEqual(cache.load(b'1'*8), None)
self.assertEqual(cache.load(b'2'*8), ('committed 2', b'e'*8))
......@@ -257,8 +270,9 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
loaded = self.load_before(b'1'*8, m64)
f1 = self.call('foo', 1, 2)
self.assertFalse(loaded.done() or f1.done())
self.assertEqual(self.pop(), [(9, False, 'loadBefore', (b'1'*8, m64)),
(10, False, 'foo', (1, 2))],
self.assertEqual(self.pop(),
[((b'1'*8, m64), False, 'loadBefore', (b'1'*8, m64)),
(6, False, 'foo', (1, 2))],
)
exc = TypeError(43)
......@@ -286,15 +300,14 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
# protocol:
protocol.data_received(sized(b'Z310'))
self.assertEqual(self.unsized(transport.pop(2)), b'Z310')
self.assertEqual(self.pop(),
[(1, False, 'register', ('TEST', False)),
(2, False, 'lastTransaction', ()),
])
self.assertEqual(self.pop(), (1, False, 'register', ('TEST', False)))
self.assertFalse(wrapper.notify_connected.called)
self.respond(1, None)
self.respond(2, b'e'*8)
self.assertEqual(self.pop(), (3, False, 'get_info', ()))
self.respond(3, dict(length=42))
# If the register response is a tid, then the client won't
# request lastTransaction
self.respond(1, b'e'*8)
self.assertEqual(self.pop(), (2, False, 'get_info', ()))
self.respond(2, dict(length=42))
# Because the server tid matches the cache tid, we're done connecting
wrapper.notify_connected.assert_called_with(client, {'length': 42})
......@@ -323,12 +336,9 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
self.assertFalse(client.connected.done() or transport.data)
protocol.data_received(sized(b'Z3101'))
self.assertEqual(self.unsized(transport.pop(2)), b'Z3101')
self.assertEqual(self.pop(),
[(1, False, 'register', ('TEST', False)),
(2, False, 'lastTransaction', ()),
])
self.respond(1, None)
self.respond(2, b'e'*8)
self.pop(4)
# We have to verify the cache, so we're not done connecting:
self.assertFalse(client.connected.done())
......@@ -361,12 +371,9 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
self.assertFalse(client.connected.done() or transport.data)
protocol.data_received(sized(b'Z3101'))
self.assertEqual(self.unsized(transport.pop(2)), b'Z3101')
self.assertEqual(self.pop(),
[(1, False, 'register', ('TEST', False)),
(2, False, 'lastTransaction', ()),
])
self.respond(1, None)
self.respond(2, b'e'*8)
self.pop(4)
# We have to verify the cache, so we're not done connecting:
self.assertFalse(client.connected.done())
......@@ -433,12 +440,9 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
cache.setLastTid('b'*8)
protocol.data_received(sized(b'Z3101'))
self.assertEqual(self.unsized(transport.pop(2)), b'Z3101')
self.assertEqual(self.pop(),
[(1, False, 'register', ('TEST', False)),
(2, False, 'lastTransaction', ()),
])
self.respond(1, None)
self.respond(2, 'a'*8)
self.pop()
self.assertFalse(client.connected.done() or transport.data)
delay, func, args, _ = loop.later.pop(1) # first in later is heartbeat
self.assert_(8 < delay < 10)
......@@ -450,12 +454,9 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
transport = loop.transport
protocol.data_received(sized(b'Z3101'))
self.assertEqual(self.unsized(transport.pop(2)), b'Z3101')
self.assertEqual(self.pop(),
[(1, False, 'register', ('TEST', False)),
(2, False, 'lastTransaction', ()),
])
self.respond(1, None)
self.respond(2, 'b'*8)
self.pop(4)
self.assertEqual(self.pop(), (3, False, 'get_info', ()))
self.respond(3, dict(length=42))
self.assert_(client.connected.done() and not transport.data)
......@@ -481,12 +482,10 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
self.assertTrue(self.is_read_only())
# The client tries for a read-only connection:
self.assertEqual(self.pop(),
[(2, False, 'register', ('TEST', True)),
(3, False, 'lastTransaction', ()),
])
self.assertEqual(self.pop(), (2, False, 'register', ('TEST', True)))
# We respond with successfully:
self.respond(2, None)
self.pop(2)
self.respond(3, 'b'*8)
self.assertTrue(self.is_read_only())
......@@ -513,12 +512,12 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
# We respond and the writable connection succeeds:
self.respond(1, None)
self.assertFalse(self.is_read_only())
# at this point, a lastTransaction request is emitted:
self.assertEqual(self.parse(loop.transport.pop()),
(2, False, 'lastTransaction', ()))
self.assertFalse(self.is_read_only())
# Now, the original protocol is closed, and the client is
# no-longer ready:
......@@ -542,11 +541,8 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
wrapper, cache, loop, client, protocol, transport = self.start()
protocol.data_received(sized(b'Z3101'))
self.assertEqual(self.unsized(transport.pop(2)), b'Z3101')
self.assertEqual(self.pop(),
[(1, False, 'register', ('TEST', False)),
(2, False, 'lastTransaction', ()),
])
self.respond(1, None)
self.pop(4)
self.send('invalidateTransaction', b'b'*8, [b'1'*8], called=False)
self.respond(2, b'a'*8)
self.send('invalidateTransaction', b'c'*8, [b'1'*8], no_output=False)
......@@ -563,11 +559,8 @@ class ClientTests(Base, setupstack.TestCase, ClientRunner):
protocol.data_received(sized(b'Z3101'))
self.assertEqual(self.unsized(transport.pop(2)), b'Z3101')
self.assertEqual(self.pop(),
[(1, False, 'register', ('TEST', False)),
(2, False, 'lastTransaction', ()),
])
self.respond(1, None)
self.pop(4)
self.send('invalidateTransaction', b'd'*8, [b'1'*8], called=False)
self.respond(2, b'c'*8)
self.send('invalidateTransaction', b'e'*8, [b'1'*8], no_output=False)
......@@ -720,7 +713,9 @@ class MemoryCache(object):
def store(self, oid, start_tid, end_tid, data):
assert start_tid is not None
revisions = self.data[oid]
revisions.append((start_tid, end_tid, data))
data = (start_tid, end_tid, data)
if not revisions or data != revisions[-1]:
revisions.append(data)
revisions.sort()
def loadBefore(self, oid, tid):
......
src/ZEO/tests/testZEO2.py
View file @ 671a5fb8
......@@ -513,6 +513,50 @@ ZEOStorage as closed and see if trying to get a lock cleans it up:
>>> logging.getLogger('ZEO').removeHandler(handler)
"""
def test_prefetch(self):
"""The client storage prefetch method pre-fetches from the server
>>> count = 999
>>> import ZEO
>>> addr, stop = ZEO.server()
>>> conn = ZEO.connection(addr)
>>> root = conn.root()
>>> cls = root.__class__
>>> for i in range(count):
... root[i] = cls()
>>> conn.transaction_manager.commit()
>>> oids = [root[i]._p_oid for i in range(count)]
>>> conn.close()
>>> conn = ZEO.connection(addr)
>>> storage = conn.db().storage
>>> len(storage._cache)
1
>>> storage.prefetch(oids, conn._storage._start)
The prefetch returns before the cache is filled:
>>> len(storage._cache) < count
True
But it is filled eventually:
>>> from zope.testing.wait import wait
>>> wait(lambda : len(storage._cache) > count)
>>> loads = storage.server_status()['loads']
Now if we reload the data, it will be satisfied from the cache:
>>> for oid in oids:
... _ = conn._storage.load(oid)
>>> storage.server_status()['loads'] == loads
True
>>> conn.close()
>>> stop()
"""
def test_suite():
return unittest.TestSuite((
......
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