blob: fe08407b1be7676610dbe87e62485dc57a1b6fd6 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
|
#------------------------------------------------------------------------
#
# In my performance tests, using this (as in dbtest.py test4) is
# slightly slower than simply compiling _db.c with MYDB_THREAD
# undefined to prevent multithreading support in the C module.
# Using NoDeadlockDb also prevent deadlocks from mutliple processes
# accessing the same database.
#
# Copyright (C) 2000 Autonomous Zone Industries
#
# License: This is free software. You may use this software for any
# purpose including modification/redistribution, so long as
# this header remains intact and that you do not claim any
# rights of ownership or authorship of this software. This
# software has been tested, but no warranty is expressed or
# implied.
#
# Author: Gregory P. Smith <greg@electricrain.com>
#
# Note: I don't know how useful this is in reality since when a
# DBDeadlockError happens the current transaction is supposed to be
# aborted. If it doesn't then when the operation is attempted again
# the deadlock is still happening...
# --Robin
#
#------------------------------------------------------------------------
#
# import the time.sleep function in a namespace safe way to allow
# "from bsddb3.db import *"
#
from time import sleep
_sleep = sleep
del sleep
import _db
_deadlock_MinSleepTime = 1.0/64 # always sleep at least N seconds between retrys
_deadlock_MaxSleepTime = 1.0 # never sleep more than N seconds between retrys
def DeadlockWrap(function, *_args, **_kwargs):
"""DeadlockWrap(function, *_args, **_kwargs) - automatically retries
function in case of a database deadlock.
This is a DeadlockWrapper method which DB calls can be made using to
preform infinite retrys with sleeps in between when a DBLockDeadlockError
exception is raised in a database call:
d = DB(...)
d.open(...)
DeadlockWrap(d.put, "foo", data="bar") # set key "foo" to "bar"
"""
sleeptime = _deadlock_MinSleepTime
while (1) :
try:
return apply(function, _args, _kwargs)
except _db.DBLockDeadlockError:
print 'DeadlockWrap sleeping ', sleeptime
_sleep(sleeptime)
# exponential backoff in the sleep time
sleeptime = sleeptime * 2
if sleeptime > _deadlock_MaxSleepTime :
sleeptime = _deadlock_MaxSleepTime
#------------------------------------------------------------------------
|
