Apache 2.2 Authentication with PostgreSQL

This is just a quick transcript of my attempts at trying to set up Apache authentication against a PostgreSQL database. I started by following the mod_auth_pgsql instructions. After doing that, I got the error:

Internal error: pcfg_openfile() called with NULL filename
(9)Bad file descriptor: Could not open password file: (null)

It looks like Apache is still trying to authenticate against an htpasswd file. I added "AuthBasicAuthoritative off" to the Apache config so that a failed file authentication passes through to the auth_pgsql authentication. That worked, but now I get

[mod_auth_pgsql.c] - ERROR - PG user admin: password mismatch

I know the password I entered was right. After reading the source code for mod_auth_pgsql, I realized that the MD5 passwords it supports are not the same as Apache's MD5 format. They're just a straight MD5 hash of the password and therefore not as secure as I might like (since they can be searched in an MD5 database). I proceeded to investigate the mod_authn_dbd instructions. I hoped that it would be able to authenticate against Apache's $apr1$ MD5 password format. After getting it set up, I got the message:

Invalid command 'DBDriver', perhaps misspelled or defined
by a module not included in the server configuration

Oops, I forgot to load mod_dbd. After loading that module, I get:

Unknown Authn provider: dbd

Oops, I forgot to load mod_authn_dbd. After loading that module, I get:

AuthDBDUserPWQuery takes one argument,
Query used to fetch password for user

Oops, I had a trailing ; after my query string. Removing the semicolon, I get:

(22)Invalid argument: DBD: failed to initialise

Based on reading the source, that looks like something to do with threads. I'll save the remaining debugging for another day. Maybe this transcript will be useful to someone out there.