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From Julian Reschke <julian.resc...@gmx.de>
Subject Re: no space left on device-exception by Property.getStream()
Date Fri, 12 Apr 2013 14:53:22 GMT
On 2013-04-12 16:24, Stefan Guggisberg wrote:
> On Fri, Apr 12, 2013 at 3:29 PM, Ulrich <Forums@gombers.de> wrote:
>> Retrieving data is completely sequential, no concurrent processing at all. I changed
the code to session.logout() and session.connect() after every step, this didn't help.
>> So the code works like this:
>> while (String path : pathList) {
>>       Session session = ...
>>       Node currentNode = session.getNode(path);
>>       Node filenode = Node.getNode("jcr:content");
>>       Property jcrdata = filenode.getProperty("jcr:data");
>>       InputStream is = jcrdata.getBinary().getStream();
>>       is.close();
>>       session.logout();
>> }
>> To be honest, this is not the exact code; the logic is spread over two classes -
but it shows the effective data flow.
>> Nevertheless - the problem remains.
>> But when I retry the whole sequence later on, I get the same result - this means
the buffer has been cleared in the meantime.
>> It looks as if there is a kind of garbage collector
> yes, it's your jvm's garbage collector.
>> , running asynchronously not fast enough for avoiding the error but being done after
a while.
> yes, that's expected behaviour. the jvm's garbage collection runs
> async with a low priority (unless you're
> running out of memory of course).
>> I tried to track the storage space by 'df -vk' but couldn't see a problem here.
> did you check inodes as well ('df -i /')?
> as i already mentioned: reading a lot of binaries will create
> a lot of temp files. those temp files will eventually be deleted
> once the gc determines that they're not used anymore (see [1]).
> but this can take some time, due to the async nature of java's gc.
> an example:
> assume you have 500mb free disk space.
> now when you're reading 1k binaries from the repository, 1mb size each,
> in a loop,  you're likely going to see said exception.
> ...

But why don't we purge the transient file once it's not needed anymore? 
Relying on GC appears to be an anti-pattern to me...

Best regards, Julian

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