Hi, I am looking for a way to improve loading times in an application, so I did a little experiment with binary CAS serialization to see if it was superior to XMI serialization. For serialization I used the CASCompleteSerializer to serialize the type-system and heaps into the same file using Java object serialization - at least that is what I understood it should do. To read in these files, I would deserialize the CASCompleteSerializer and initialize a CAS from it using CASImpl.reinit().
96.400 files plain text (uncompressed) : 581.865.593 Byte binary (serialized java, gzip) : 0:47:02.835 3.555.449.597 Byte xmi (gzip) : 1:20:31.535 4.712.633.769 Byte So binary takes about 60% of the time xmi serialization would need and uses about 75% of the space. I didn't do reading experiment yet, but I suppose the improvement should be on a similar level, if not better. I am also not sure yet about the draw-backs of binary serialization and in which scenarios they apply. The draw-backs I saw so far are: - Type-system is stored redudantly in every output file. - The type system configured with CASImpl.reinit() may be different from the one which was used to initialize the pipeline, CAS-based annotators relying on typeSystemInit() may not be configured with the correct types - this is a hypothesis I didn't test. - Serialized Java objects may become due to refactoring within the UIMA framework. However, there is yet another binary CAS serialization in UIMA which uses the DataOutputStream and may be more stable. Did anybody ever use any form of binary CAS serialization outside Vinci/UIMA-AS? Cheers, -- Richard -- ------------------------------------------------------------------- Richard Eckart de Castilho Technical Lead Ubiquitous Knowledge Processing Lab (UKP-TUD) FB 20 Computer Science Department Technische Universität Darmstadt Hochschulstr. 10, D-64289 Darmstadt, Germany phone [+49] (0)6151 16-7477, fax -5455, room S2/02/B117 [email protected] www.ukp.tu-darmstadt.de Web Research at TU Darmstadt (WeRC) www.werc.tu-darmstadt.de -------------------------------------------------------------------
