Thursday, February 2, 2012

Playing with PELAGIOS: Dealing with a bazillion RDF files

Latest in a Playing with PELAGIOS series

Some of the PELAGIOS partners distribute their annotation RDF in a relatively small number of files. Others (like SPQR and ANS) have a very large number of files. This makes the technique I used earlier for adding triples to the database ungainly. Fortunately, 4store provides some command line methods for loading triples.

First, stop the 4store http server (why?):
$ killall 4s-httpd
Try to import all the RDF files.  Rats!
$ 4s-import -a pelagios *.rdf
-bash: /Applications/ Argument list too long
Bash to the rescue (but note that doing one file at a time has a cost on the 4store side):
$ for f in *.rdf; do 4s-import -av pelagios $f; done
Reading <file:///Users/paregorios/Documents/files/P/pelagios-data/coins/0000.999.00000.rdf>
Pass 1, processed 10 triples (10)
Pass 2, processed 10 triples, 8912 triples/s
Updating index
Index update took 0.000890 seconds
Imported 10 triples, average 4266 triples/s
Reading <file:///Users/paregorios/Documents/files/P/pelagios-data/coins/0000.999.101.rdf>
Pass 1, processed 11 triples (11)
Pass 2, processed 11 triples, 9856 triples/s
Updating index
Index update took 0.000936 seconds
Imported 11 triples, average 4493 triples/s
Reading <file:///Users/paregorios/Documents/files/P/pelagios-data/coins/0000.999.10176.rdf>
Pass 1, processed 8 triples (8)
Pass 2, processed 8 triples, 6600 triples/s
Updating index
Index update took 0.000892 seconds
Imported 8 triples, average 3256 triples/s
This took a while. There are 86,200 files in the ANS annotation batch.

Note the use of the -a option on 4s-import to ensure the triples are added to the current contents of the database, rather than replacing them! Note also the -v option, which is what gives you the report (otherwise, it's silent and that makes my ctrl-c finger twitchy).

Now, back to the SPARQL mines.

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