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NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.
To learn about what's going on, see About the Archive Site.
Hi Lak: This behavior is controlled by the singleton class ucar.nc2.util.DiskCache. See the javadocs for that: http://www.unidata.ucar.edu/software/netcdf-java/v4.0/javadoc/index.html An overview is at: http://www.unidata.ucar.edu/software/netcdf-java/tutorial/NetcdfFile.html#DiskCache see embedded comments below: Valliappa Lakshmanan wrote: > I've been using the Java Netcdf API and am running into several issues > with the temporary files that are created. > > For example, when a gzipped NetCDF file is read, an uncompressed > version is written to disk before it is read. I assume that this is > because the NetCDF API allows for file seeks etc. > which wouldn't be possible if the file remained gzipped. But (and this > is the problem), the uncompressed > file is stored in the SAME directory as the original file. This causes > three major problems (in increasing order > of severity): > (a) The data directory (which would be considered read-only) is being > modified. This causes problems because of the I/O optimizations that we do > on real-time systems you can make all temp files go to a different directory. > (b) The temporary file is not automatically cleaned up, so these > temporaries start to fill up the disk. see overview for example on how to cleanup. > But removing the temporary file when the original file is closed > is not enough because of problem (c). > (c) if there are two simultaneous programs reading a gzipped file, > then a potential for race conditions exists yes, this is a good point. the default case is optimized for single-threaded use. The TDS uses a different strategy for this reason. Do you actually see this problem? If so, in what context? > > The same problem seems to exist when reading a Grib1 file (a .gbx > temporary file is created). > > Is there any work-around for this problem? > > Lak > > p.s. I suggest the consistent use of java.io.File's createTempFile() ... That might be a useful option. Do you actually need it, or is this theoretical? The default case is to avoid the overhead of unzipping/indexing more than once. > > > ------------------------------------------------------------------------ > > _______________________________________________ > netcdfgroup mailing list > netcdfgroup@xxxxxxxxxxxxxxxx > For list information or to unsubscribe, visit: > http://www.unidata.ucar.edu/mailing_lists/
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