At 12:14 AM 5/20/00 -0400, Bruce Momjian wrote:
> We have shared buffers that are mapped into the address space of each
> backend. [ ... ]
> I wonder how SDB performs such file scans.
Berkeley DB is an embedded toolkit, and works hard to provide mechanism
in place of policy. That is to say, you can request memory-mapped
access to database files, or you can use a shared memory buffer cache.
We give you the tools to do what you want. We try not to force you to
do what we want.
We don't do query processing, we do fast storage and retrieval. Query
planning and optimization, including access path selection and buffer
management policy selection, get built on top of Berkeley DB. We offer
a variety of ways, via the API, to control the behavior of the lock,
log, shmem, and transaction subsystems.
mike