> In my current project I expect the total size of the indexes to exceed > by far the size of the data indexed, but because Berkeley does not > support multiple indexed columns (i.e. only one key value column as > index) if I access the database files one after another (not > simultaneously) it should work without problems with RAM, right?
You can maintain multiple secondary indices on a primary database. BDB isn't a "relational" database, though, so speaking of columns confuses the issue. But you can have one database with primary key -> value, then multiple secondary key -> primary key databases (with bdb transparently providing the secondary key -> value mapping if you desire). > Do the data volume required to store the key values have impact on the > size of the index pages or does the size of the index pages depend only > on the number of records and kind of the index (btree, hash)? For btree, it is the size of the keys that matters. I presume the same is true for the hashtable, but I'm not certain. > What is the upper limit of number of records in practice? Depends on sizes of the keys and values, page size, cache size, and physical limitations of your machine. -Mike -- http://mail.python.org/mailman/listinfo/python-list
