Comment 7 for bug 638584

(In reply to comment #4)
> WONTFIX -

> rpm might switch to btree by default for other reasons (such as
> potentially better performance)

Expecting hash was chosen because rpm does not need to traverse the entries in sorted order. In such case btree is slower (O(log(n)) than hash (O(1)).
It is just the current luck of better compatibility that may be worth the change (while the performance degradation may not be measurable).

> while a future rpm version might be able to deal with on-the-fly btree/ht
> detection/conversion, there's little chance that such code would end up in
> existing RHEL and even less chance for EOL Fedora version.

This is invalid argument. Current (F12) db4 btree is still compatible with existing epel-4 btree format. I did file this Bug for Rawhide, not for F9 or RHEL4. rpm change for F13 was the intended target of this Bug which would ease the epel-4 maintenance already in several months.

> Of course you're free to configure your own systems and chroots to use btree
> instead of hash while the luck with compatibility lasts.

I already do workaround rpm4 by regular --rebuilddb (Bug 464752) and occasional db*_{dump,load} (this Bug). Suggesting workarounds is not the goal of a package maintainer assignment.