TDB: using the jenkins hash for non-persistent tdbs

Stefan (metze) Metzmacher metze at
Mon Sep 20 03:41:08 MDT 2010

Hi Rusty,

> On Fri, 17 Sep 2010 11:55:02 pm Stefan (metze) Metzmacher wrote:
>> If the jenkins hash is used, we set the rwlocks field in the tdb header
>> to a magic value.
>> Current tdb versions expect this to be 0 and fail the open.
> Unfortunately, this is an ABI break.  Someone using TDB and a non-default
> hash won't be able to open their old TDBs any more.

I the caller specifies a hash function, we still use that one.
So I don't see how this breaks existing users.

> My original version used the same trick, but I reluctantly replaced it with
> your other 100% backwards-compatible version.  That's the price we pay for
> exporting tdb as a standalone library.
> The only way we could do this is as a separate flag to tdb_open, eg.
> TDB_INCOMPATIBLE_HASH or something.  I'm not sure that's worthwhile though?

I'd like to avoid that.


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