Known Bugs and Limitations The known limitations include the BSDDB performance issues related to caching and the memory size. As long as the BSDDB cache fits completely into the available memory on the system, the performance should be adequate. When the cache size exceeds that of the free memory and portions of database cache start to be swapped onto the disk, the performance degrades appreciably. This can be solved by adjusting the BSDDB cache size for the large databases.