RE: back-bdb DB_RECOVER and soft restart

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

> -----Original Message-----
> From: owner-openldap-devel@OpenLDAP.org
> [mailto:owner-openldap-devel@OpenLDAP.org]On Behalf Of Lars Uffmann

> On Tue, 2003-09-16 at 02:01, Matthew Hardin wrote:
>
> Why make it so complicated?
>
> http://www.sleepycat.com/docs/ref/transapp/app.html
>
> The easy way:
>
> It greatly simplifies matters that recovery may be performed
> regardless
> of whether recovery strictly needs to be performed; that is, it is not
> an error to run recovery on a database for which no recovery is
> necessary. Because of this fact, it is almost invariably simpler to
> ignore the previous rules about shutting an application down cleanly,
> and simply run recovery each time a thread of control accessing a
> database environment fails for any reason, as well as before accessing
> any database environment after system reboot.
>
> Why choose the "hard way"?

That's what back-bdb used to do, in its infancy. It turned out to cause slapd
startup to be very slow. During recovery the BDB cache is destroyed and
recreated, which makes for a lot of unnecessary data churn, and has a large
negative impact on performance until the cache gets repopulated. Yes it's
true that it is safe to run recovery even when it's not needed, but it is far
from desirable.

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