[pybsddb] Making calls to keys() more efficient (or, how to do inequality gets on keys?)

[Jesus Cea]

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On 18/06/10 16:16, Denis Papathanasiou wrote:
> Unfortunately, the db in question is not a btree, so I couldn't use the
> cursor idea.

You could "convert it" to a btree easily, surely. I would recomend you
to do.

You only need to open new databases with "DB_BTREE" instead of
"DB_HASH". To convert a old database, you only need to create a new
"DB_BTREE" database and copy the values over with a cursor. It is a
simple and fast, one time operation.

Usually HASH databases have better performance when you have huge number
or registers accessed at random, but I suspect you have a pretty high
locality of reference, so a BTREE would be more performant (because it
keeps key-close registers close in disk too).

Please, evaluate seriously to migrate to btree. Collect stats with both
approaches, and decide with real hard data at hand.

> Is range key request limited to btrees? If not, then I'd vote for it to
> be included in pybsddb as well.

Only btree allows ranges, because hashes doesn't preserve key ordering
in disk.

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