Mercurial > p > roundup > code
annotate roundup/backends/locking.py @ 6565:2c2dbfc332ba
Try to handle multiple connections better.
The session database is a hot spot. When multiple requests (e.g. 20)
come in at the same time session database contention can get great.
The original code didn't retry session database access when the open
failed. This resulted in errors at the client.
The second pass delayed 0.01 seconds and retried. It was better but we
still had multiple second stalls. I think the first request got in,
everybody else backed up and then retried at the same time. Again they
stepped on each other. With logging I would see many counters go all
the way to low single digits or to -1 indicating falure.
This pass uses randomint to generate delays from 0-.125 seconds in 5ms
increments. This performs better in testing. I rarely saw a counter
less than 13 (2 failed retries). Current logging starts after 6
failures and counts down until success or failure.
| author | John Rouillard <rouilj@ieee.org> |
|---|---|
| date | Thu, 16 Dec 2021 20:02:00 -0500 |
| parents | 6e3e4f24c753 |
| children | 608f140237c9 |
| rev | line source |
|---|---|
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1 #! /usr/bin/env python |
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2 # Copyright (c) 2002 ekit.com Inc (http://www.ekit-inc.com/) |
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3 # |
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4 # Permission is hereby granted, free of charge, to any person obtaining a copy |
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5 # of this software and associated documentation files (the "Software"), to deal |
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6 # in the Software without restriction, including without limitation the rights |
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7 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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8 # copies of the Software, and to permit persons to whom the Software is |
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9 # furnished to do so, subject to the following conditions: |
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10 # |
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11 # The above copyright notice and this permission notice shall be included in |
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12 # all copies or substantial portions of the Software. |
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13 # |
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14 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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15 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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16 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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17 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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18 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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19 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
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20 # SOFTWARE. |
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21 |
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22 '''This module provides a generic interface to acquire and release |
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23 exclusive access to a file. |
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24 |
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25 It should work on Unix and Windows. |
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26 ''' |
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2005
fc52d57c6c3e
documentation cleanup
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27 __docformat__ = 'restructuredtext' |
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28 |
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Beginnings of a big code cleanup / modernisation to make 2to3 happy
Richard Jones <richard@users.sourceforge.net>
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29 from roundup.backends import portalocker |
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30 |
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31 def acquire_lock(path, block=1): |
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32 '''Acquire a lock for the given path |
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33 ''' |
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34 file = open(path, 'w') |
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35 if block: |
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36 portalocker.lock(file, portalocker.LOCK_EX) |
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37 else: |
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38 portalocker.lock(file, portalocker.LOCK_EX|portalocker.LOCK_NB) |
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39 return file |
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40 |
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509a101305da
node ids are now generated from a lockable store - no more race conditions
Richard Jones <richard@users.sourceforge.net>
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41 def release_lock(file): |
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509a101305da
node ids are now generated from a lockable store - no more race conditions
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42 '''Release our lock on the given path |
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509a101305da
node ids are now generated from a lockable store - no more race conditions
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43 ''' |
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509a101305da
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44 portalocker.unlock(file) |
