RE: back-bdb future

["Howard Chu" <hyc@highlandsun.com>]

> -----Original Message-----
> From: Kurt D. Zeilenga [mailto:Kurt@OpenLDAP.org]

> >My wording may not have been too clear. I am not talking
> about using a
> >memory-only BDB database to store entries in a
> disk-datbase-style format. I
> >mean using the memory-only database to store the pointers to
> the cached
> >entries, instead of using libavl. The question is whether a
> hashing scheme,
> >or a Btree scheme, might be more efficient than an AVL tree.
>
> On nice thing about using BDB here is that they provide a
> common API for both Btree and Hash structures.

yes... so it shouldn't be too painful to benchmark all 3.

> >However, your point about DB overhead probably still stands.
>
> In back-bdb, that overhead will likely have to be increased due
> to read transactions.   The only way I can see to resolve the
> read deadlock problems otherwise would be to ensure backend
> is never reading and writing at the same time.

Do we still have read deadlock problems? I haven't seen any. I believe read
transactions can only hurt things, because locks are held for the life of the
transaction. Reads outside of transactions release their locks right away,
which assures that their locks cause the least possible interference.

  -- Howard Chu
  Chief Architect, Symas Corp.       Director, Highland Sun
  http://www.symas.com               http://highlandsun.com/hyc
  Symas: Premier OpenSource Development and Support