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Re: slapadd(8), database order

Maybe the thing to do is:
  a) have back-bdb check for existance of parents
  b) provide an LDIF ordering tool

or, provide a ID defragmentation tool :-).

At 10:03 PM 2002-09-08, Howard Chu wrote:
>We need to add some back-bdb specific notes to this manpage, but I wasn't
>sure how I wanted to word it.
>
>slapadd accepts LDIF input in slapcat/database order. When B-trees are used,
>database order is actually the same as the original input order, it is not
>random/unpredictable as with the hash database.
>
>In back-bdb it is important that slapadd's input be well-ordered, with
>superior entries added before child entries. If entries are added in random
>order, the subtree index will quickly become useless as it grows in size.
>When a subtree index slot gets large enough to be converted from an explicit
>list into a range, the number of entries represented by the range can far
>exceed the number of entries represented by the list.
>
>For example, you may have an explicit list with IDs 10, 500, 999999. When
>this list grows large enough to be converted into a range, instead of going
>from 65536 IDs to 65537 IDs, this list will cover 999990 IDs just from adding
>one ID to the list, and the vast majority of the IDs probably aren't in the
>subtree of interest.
>
>This situation can also arise during the life of a DIT from various ldapadd
>operations, but if you start with a well-ordered input to slapadd it will
>take a long time before it becomes a problem. In particular, when you start
>with well-ordered input, it will be impossible for a subtree index slot to
>erroneously include a superior node's ID. With a random input, there are no
>such guarantees.
>
>  -- Howard Chu
>  Chief Architect, Symas Corp.       Director, Highland Sun
>  http://www.symas.com               http://highlandsun.com/hyc
>  Symas: Premier OpenSource Development and Support