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From robert engels <>
Subject Re: [jira] Commented: (LUCENE-665) temporary file access denied on Windows
Date Wed, 13 Sep 2006 19:58:06 GMT
Also, what was stated is that "this is not a safe assumption" is  
ludicrous. It happens to not be safe because X software package that  
was installed is holding locks on files.... If could be that Y  
software package (virus scanner !) deletes files automatically when  
it doesn't recognize an extension - or possibly one of the lucene  
index files ends up matching some virus signature.

You always must be aware of the environment in which you install  
anyway software. Having indexing software or virus scanning software  
run on the directories that contains Lucene files is just a bad  
(incorrect) deployment - will perform badly as best, and not at all  
at worst.

On Sep 13, 2006, at 2:52 PM, Bruce Ritchie wrote:

> While what you say is true about indexing should be disabled, that
> really doesn't solve the actual issue. Administrators of applications
> using lucene often do not have control over the actual machine and  
> thus
> cannot determine what is and is not installed. Besides that, many  
> of us
> do development on Windows machines and don't want the hassle of being
> forced to run the application either remotely on a unix box or in a VM
> just to work around this issue. I've hit this exact issue during
> development - it's truly an annoying issue that a simple sleep/retry
> loop should resolve.
> Regards,
> Bruce Ritchie
> -----Original Message-----
> From: robert engels []
> Sent: Wednesday, September 13, 2006 3:41 PM
> To:
> Subject: Re: [jira] Commented: (LUCENE-665) temporary file access  
> denied
> on Windows
> This is a server application. Windows indexing service should be  
> disable
> on the directories that contain Lucene locks and files.
> This is the same procedure that would be required for any database.
> On Sep 13, 2006, at 2:27 PM, Michael McCandless (JIRA) wrote:
>>     [
>> page=comments#action_12434527 ]
>> Michael McCandless commented on LUCENE-665:
>> -------------------------------------------
>> I do think we should make Lucene robust to "windows change log"
>> software.
>> We could take the position that you have to uninstall such software
>> because they "conflict" with Lucene, but I don't think that's
>> realistic.  Apparently many packages use this convenient API and that
>> will only get worse with time.
>> I would put this under the "Lucene should assume the least common
>> denominator of filesystem's capabilities" umbrella.  Meaning, Lucene
>> now assumes it can rename files right after closing them, but on
>> Windows this isn't a safe assumption so if possible we should change
>> the index format to not require this.
>> I will try to reproduce this bug with my [upcoming] changes for
>> lockless commits (numbered segments files) -- the lockless commits
>> changes do much less file renaming, so the issue should be rarer (but
>> could still occur).
>>> temporary file access denied on Windows
>>> ---------------------------------------
>>>                 Key: LUCENE-665
>>>                 URL:
>>>             Project: Lucene - Java
>>>          Issue Type: Bug
>>>          Components: Store
>>>    Affects Versions: 2.0.0
>>>         Environment: Windows
>>>            Reporter: Doron Cohen
>>>         Attachments: FSDirectory_Retry_Logic.patch,
>>> FSDirs_Retry_Logic_3.patch, Test_Output.txt,
>>> When interleaving adds and removes there is frequent opening/  
>>> closing
>>> of readers and writers.
>>> I tried to measure performance in such a scenario (for issue 565),
>>> but the performance test failed  - the indexing process crashed
>>> consistently with file "access denied" errors - "cannot create a  
>>> lock
>>> file" in "lockFile.createNewFile()" and "cannot rename file".
>>> This is related to:
>>> - issue 516 (a closed issue: "TestFSDirectory fails on Windows") -
>>> - user list questions due to file errors:
>>>   -
>>> Denied-errors-tf1649795.html
>>>   -
>>> windows-service-on-xp%2C-crashing-tf2053536.html
>>> - discussion on lock-less commits
>>> commits-tf2126935.html My test setup is: XP (SP1), JAVA 1.5 - both
>>> SUN and IBM SDKs.
>>> I noticed that the problem is more frequent when locks are  
>>> created on
>>> one disk and the index on another. Both are NTFS with Windows
>>> indexing service enabled. I suspect this indexing service might be
>>> related - keeping files busy for a while, but don't know for sure.
>>> After experimenting with it I conclude that these problems - at  
>>> least
>>> in my scenario - are due to a temporary situation - the FS, or the
>>> OS, is *temporarily* holding references to files or folders,
>>> preventing from renaming them, deleting them, or creating new files
>>> in certain directories.
>>> So I added to FSDirectory a retry logic in cases the error was
>>> related to "Access Denied". This is the same approach brought in
>>> service-on-xp%2C-crashing-tf2053536.html - there, in addition to the
>>> retry, gc() is invoked (I did not gc()). This is based on the
>>> *hope* that a access-denied situation would vanish after a small
>>> delay, and the retry would succeed.
>>> I modified FSDirectory this way for "Access Denied" errors during
>>> creating a new files, renaming a file.
>>> This worked fine for me. The performance test that failed before,  
>>> now
>>> managed to complete. There should be no performance implications due
>>> to this modification, because only the cases that would otherwise
>>> wrongly fail are now delaying some extra millis and retry.
>>> I am attaching here a patch - FSDirectory_Retry_Logic.patch - that
>>> has these changes to FSDirectory.
>>> All "ant test" tests pass with this patch.
>>> Also attaching a test case that demostrates the problem - at  
>>> least on
>>> my machine. There two tests cases in that test file - one that works
>>> in system temp (like most Lucene tests) and one that creates the
>>> index in a different disk. The latter case can only run if the path
>>> ("D:" , "tmp") is valid.
>>> It would be great if people that experienced these problems could  
>>> try
>>> out this patch and comment whether it made any difference for them.
>>> If it turns out useful for others as well, including this patch in
>>> the code might help to relieve some of those "frustration" user
>>> cases.
>>> A comment on state of proposed patch:
>>> - It is not a "ready to deploy" code - it has some debug printing,
>>> showing the cases that the "retry logic" actually took place.
>>> - I am not sure if current 30ms is the right delay... why not 50ms?
>>> 10ms? This is currently defined by a constant.
>>> - Should a call to gc() be added? (I think not.)
>>> - Should the retry be attempted also on "non access-denied"
>>> exceptions? (I think not).
>>> - I feel it is somewhat "woodoo programming", but though I don't  
>>> like
>>> it, it seems to work...
>>> Attached files:
>>> 1. - the LONG test that fails  
>>> on XP
>>> without the patch and passes with the patch.
>>> 2. FSDirectory_Retry_Logic.patch
>>> 3. Test_Output.txt- output of the test with the patch, on my XP.
>>> Only the createNewFile() case had to be bypassed in this test, but
>>> for another program I also saw the renameFile() being bypassed.
>>> - Doron
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