bibtex export results in empty file

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2011-02-03
2013-05-28
  • Tobias Lippert
    Tobias Lippert
    2011-02-03

    Hello,
    I have collected 135 entries in a group and want to export all of them to bibtex. But I obtain an empty show.php in firefox and the following error message in chrome:
    Fehler 324 (net::ERR_EMPTY_RESPONSE): Unbekannter Fehler.
    I assume that this has to do with too many entries, since it worked fine before.
    Are there any known issues with bibtex export and a high number of entries? Exporting to odf xml works fine, but Endnote and mods export is broken too.

    I use mysql 5.0 and php 4.3.8.

    Thanks in advance
    Tobias

     
  • Tobias Lippert
    Tobias Lippert
    2011-02-03

    The error disappears when I export only 128 records.

     
  • With very large datasets, you have lots of potential problems: execution timeouts, exceeding maximum memory allocation or file size limits, browser size/time limits.  To know which of these is at fault, you would need to enable logging of php+apache & would inspect the server's error log.

     
  • Tobias Lippert
    Tobias Lippert
    2011-02-04

    Thank you for your quick reply! I really appreciate that.
    I found the error in the log. Sorry, I dont know anything about php. And especially not where to look for errors.
    This problem was caused by too much memory consumption. The script needs more than the allowed 32 MB.
    However, this seems to be quite a lot of memory. Is there anything I can do to reduce the memory consumption?

     
  • Tobias Lippert
    Tobias Lippert
    2011-02-04

    I have learned some basic php and looked a bit into the code and found that every mods xml node of  has about 200kb of size. This is quite a lot. I do not know why it takes so much memory (that is about 100 pages of text). I have tried to remove the keywords (since there a lot of them if you import the entries via pubmed) but the xml trees were still quite big.

    I suppose that the xml implementation that is used is very inefficient.
    Are there any standard xml implementations that use less memory on php? This could help to reduce the memory footprint

     
  • We have discussed replacing the ActiveLink XML parser that we now use, as it is no longer maintained.  I have not yet tried to see if SimpleXML (or others) can handle the fairly large XML files you're making (I'd expect the final MODS file to be something like half a megabyte).