temporary file access denied on Windows
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Key: LUCENE-665
URL: http://issues.apache.org/jira/browse/LUCENE-665
Project: Lucene - Java
Issue Type: Bug
Components: Store
Affects Versions: 2.0.0
Environment: Windows
Reporter: Doron Cohen
Attachments: FSDirectory_Retry_Logic.patch, Test_Output.txt,
TestInterleavedAddAndRemoves.java
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") -
http://issues.apache.org/jira/browse/LUCENE-516
- user list questions due to file errors:
-
http://www.nabble.com/OutOfMemory-and-IOException-Access-Denied-errors-tf1649795.html
-
http://www.nabble.com/running-a-lucene-indexing-app-as-a-windows-service-on-xp%2C-crashing-tf2053536.html
- discussion on lock-less commits
http://www.nabble.com/Lock-less-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
http://www.nabble.com/running-a-lucene-indexing-app-as-a-windows-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. TestInterleavedAddAndRemoves.java - 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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