The three binary formats supported by pg_dump are the custom, the directory and the tar format. The first two can be accessed randomly by the restore program and have the parallel restore support, being the best choice for having a flexible and reliable restore. Before the the 9.3 the only format supporting the parallel restore was the custom. With this version the directory format accepts the -j switch. This feature, combined with the parallel dump seen in 9.

Finally I’ve found some time to complete a working prototype of the new library pg_chamelion. The github repos is here, https://github.com/the4thdoctor/pg_chameleon, please fork it if you want to debug or give me some feedback. The library exports the metadata from mysql using sqlalchemy. The informations are used by the PostgreSQL library to rebuild the schema in a PostgreSQL database. Finally the data is dumped to multiple files in CSV format and reloaded into PostgreSQL using the copy_expert command.