Commit e387ad59 authored by Julien Muchembled's avatar Julien Muchembled

importer: fix possible data loss on writeback

If the source DB is lost during the import and then restored from a backup,
all new transactions have to written back again on resume. It is the most
common case for which the writeback hits the maximum number of transactions
per partition to process at each iteration; the previous code was buggy in
that it could skip transactions.
parent 48d936cb
......@@ -678,6 +678,7 @@ class WriteBack(object):
_changed = False
_process = None
chunk_size = 100
def __init__(self, db, storage):
self._db = db
......@@ -737,7 +738,6 @@ class WriteBack(object):
def iterator(self):
db = self._db
np = self._np
chunk_size = max(2, 1000 // np)
offset_list = xrange(np)
while 1:
with db:
......@@ -748,23 +748,26 @@ class WriteBack(object):
if np == len(db._readable_set):
while 1:
tid_list = []
loop = False
max_tid = MAX_TID
for offset in offset_list:
x = db.getReplicationTIDList(
self.min_tid, MAX_TID, chunk_size, offset)
self.min_tid, max_tid, self.chunk_size, offset)
tid_list += x
if len(x) == chunk_size:
loop = True
if tid_list:
for tid in tid_list:
if self._stop.is_set():
yield TransactionRecord(db, tid)
if len(x) == self.chunk_size:
max_tid = x[-1]
if not tid_list:
for tid in tid_list:
if self._stop.is_set():
yield TransactionRecord(db, tid)
if tid == max_tid:
self.min_tid = util.add64(tid, 1)
if loop:
self.min_tid = util.add64(tid, 1)
if not self._event.is_set():
......@@ -21,9 +21,11 @@ import os, random, shutil, time, unittest
import transaction, ZODB
from neo.client.exception import NEOPrimaryMasterLost
from neo.lib import logging
from neo.lib.util import u64
from neo.lib.util import p64, u64
from neo.master.transactions import TransactionManager
from import getAdapterKlass, importer, manager
from import Repickler, TransactionRecord
from import \
Repickler, TransactionRecord, WriteBack
from .. import expectedFailure, getTempDirectory, random_tree, Patch
from . import NEOCluster, NEOThreadedTest
from ZODB import serialize
......@@ -179,7 +181,7 @@ class ImporterTests(NEOThreadedTest):
del db_list, iter_list
#del zodb[0][1][zodb.pop()[0]]
# Start NEO cluster with transparent import.
with NEOCluster(importer=importer) as cluster:
with NEOCluster(importer=importer, partitions=2) as cluster:
# Suspend import for a while, so that import
# is finished in the middle of the below 'for' loop.
# Use a slightly different main loop for storage so that it
......@@ -243,10 +245,10 @@ class ImporterTests(NEOThreadedTest):
@unittest.skipUnless(importer.FORK, 'no os.fork')
def test1(self):
def testMultiProcessWriteBack(self):
def testThreadedWriteback(self):
def testThreadedWritebackAndDBReconnection(self):
# Also check reconnection to the underlying DB for relevant backends.
tid_list = []
def __init__(orig, tr, db, tid):
......@@ -274,6 +276,24 @@ class ImporterTests(NEOThreadedTest):
self.assertEqual(len(tid_list), 11)
def testThreadedWritebackWithUnbalancedPartitions(self):
N = 7
nonlocal_ = [0]
def committed(orig, self):
if nonlocal_[0] > N:
def _nextTID(orig, self, *args):
if args:
return orig(self, *args)
nonlocal_[0] += 1
return orig(self, p64(nonlocal_[0] == N), 2)
with Patch(importer, FORK=False), \
Patch(TransactionManager, _nextTID=_nextTID), \
Patch(WriteBack, chunk_size=N-2), \
Patch(WriteBack, committed=committed):
self.assertEqual(nonlocal_[0], 10)
def testMerge(self):
multi = 1, 2, 3
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