INFORMATION ON BUILDING/USING EZMLM WITH POSTGRESQL SUPPORT

Original source:
(c) 1999, Frederik Lindberg, lindberg@id.wustl.edu
		You may use under GPL.

and for PostgreSQL modifications:
(c) 1999, Magnus Stålåker, stalaker@umc.se

Rewritten as a plugin by:
(c) 2007 Bruce Guenter, bruce@untroubled.org

For information on PostgreSQL, see http://www.postgresql.org/

This version of the PostgresSQL supports the basic subscriber address
database and subscription logging. The log that is searched by the -log.
command is the local listdir/Log file, NOT the SQL database. Message
logging is not supported, and central admin of list clusters is not
supported. Still, the current support covers the functionality used in
99% of lists.

Most of this information is available in FAQ.

If you are interested in contributing/testing a subscriber db interface
for another SQL server, please see README.std and the routines here,
and contact bruce@untroubled.org (it may already be in process). See end
of this file for other ways to contribute.

conf-mysql must be edited to reflect your system. On many systems, you
also need to include ``-lsocket'', as well as change the paths to the
/usr/local equivalents. For the i386.rpm-based systems, you need at
least MySQL-devel to build the files. Look at your mysql docs for more info.

TABLES USED FOR (My)SQL SUPPORT

The basic philosophy is that the database can be on any host (if you use
SENDER restrictions, connectivity to the main host is more important than
to the sublists), and you choose the database and "table root" names. The
default database is ``ezmlm'' and the default table root is ``list''. Each
list has a separate table root. Any number of lists can share a database.

The main list address table is named with the table root only, others have
that name with various suffixes. In the following ``list'' is used as the
table root.

ADDRESS TABLES
list		subscriber addresses
list_slog	subscriber address log
list_allow	subscriber aliases for posts on SENDER checked lists.
list_allow_slog	subscriber log for list_allow
list_deny	blacklisted addresses for posts on SENDER checked lists.
list_deny_slog	log for list_deny.
list_mod	moderator addresses
list_mod_slog	log for list_mod
list_digest	subscriber log for digest list.
list_digest_slog	log for list_digest

MESSAGE LOGGING TABLES (not supported by this version of the interface)
list_cookie	message cookie table for main list
list_mlog	message logging table for main list
list_digest_cookie	message cookie table for digest list
list_digest_mlog	message logging table for digest list

SUBLIST SPLIT TABLES (not supported by this version of the interface)
list_name	sublist split table for main list
list_digest_name	sublist split table for digest list.

The address tables contain (address,domain,hash,h,num). For normal
lists only the address field is used. For main->sublist clusters, the other
fields are used for load splitting. The domain is the first up to 3 characters
of the last part of the domain name. The hash is a address hash [0-52] differnt
from the one used by ezmlm for splitting within DIR/subscribers. When using
the address field as a primary key, the size of the index was unreasonable.
Therefore, ``num'' is used as a dummy primary key, and ``h'' (a 32 bit hash
of the address) is used as an index. This markedly speeds up (un)sub with
large (>30,000 rows) subscriber tables.

The *_slog tables contain the same info as DIR/Log, i.e. address, timestamp,
entry-type, entry-direction, and fromline. The entry-type is the first letter
of the type of entry (probe, manual, `` '' for normal), entry-direction is
``+'' for addition, ``-'' for removal. Fromline is the From: header contents
taken from the subscribe confirm message or from ezmlm-sub (if used with -n).
It is blank for all address removals, and may be blank also for additions. It
is used by the list-log.xx command. It is trivial to JOIN this table with the
address table to get e.g. subsciber names, subscription dates, etc. These
tables also have the 32-bit hash ``h'' as an index. Joins should be done on
``h'' as well as ``address'' for better performance.

The *_cookie tables contain message number, timestamp, and cookie. For each
message a pseudo-random cookie is generated that is ``impossible'' to guess
beforehand. For lists with sublists, this is used as basic authentication,
i.e. the sublist will refuse to process a message that doesn't contain the
correct cookie or that the sublist has already successfully processed.

The *_mlog tables contain log entries from main and sublists. These are
timestamp, listno, done. Listno is the lowest listnumber for an active list
entry with the name of this sublist as looked up in the *_name table. Done
is -1 for bounce, 0 for arrived, 1 for finished processing, and 2 for receipt
received. The routines are set up so that only the first attempt for each
combination (listno,code) is logged.

The *_name tables contain listno,name,domain,hash_lo,hash_hi,msgnum_lo,
msgnum_hi,notuse. Listno is auto_increment and unique. Name is the name of the
sublist. domain is the last up to 3 characters of the top domain name for
addresses served by this list (default = ''). It is is '', the list servers
all_domains_that_are_not_served_by_another list (in addition to domain '').
Of the addresses that match the domain criterion, the list serves the subset
with hash between hash_lo and hash_hi (defaults 0, 52). Any entry is ingnored if
notuse != 0 OR the current message number is not between msgnum_lo and
msgnum_hi.

For normal lists that are not distributed (i.e. they are a single list),
entries in the *_name tables are not needed and logging is not very
relevant.

For most lists, the only addresses that are stored in the SQL database are
the subscribers of list and digest, and the ``allow'' aliases. It is NOT
normally advisable to store moderator addresses there, since they are
needed only at the main list and secrecy is more important. ``Deny'' addresses
are few and again only needed at the main list. ``Allow'' are put in the
SQL database when using the default ezmlmrc file only to make all relevant
addresses manipulatable via the SQL server. The other tables are created, in
case they are  wanted (the cost for having them as empty table is zero). The
basedir/sql file is the decision point. If it exists, an SQL table is used;
if not a local ezmlm db is used.

CONTRIBUTIONS REQESTED

I would be very grateful if there are users out there willing to do any of
the following and contribute it to this package. Please check with me first
(bruce@untroubled.org), as the project may already be in progress/done.

1. Interfaces for other SQL servers. Oracle, SyBase, ...

2. A GUI admin utility to add/remove/manipulate the sublist split, essentially
   by modifying list_[digest_]name in a safe way. Ideally WWW if it can be
   done securely. If you use some standard interface (JDBC/DBD) it would be
   useful also with other SQL severs. This could even be an Access program
   using ODBC, although writing it for a platform running qmail/ezmlm makes
   most sense.

3. a WWW GUI that allows users to subscribe/unsubscribe in a safe way. A random
   password would be created the first time and stored in a new address->pw
   table and mailed to the subscriber address. With that password, the user
   would be able to [un]subscribe to lists, edit the name (for compatibility
   implemented by adding a subscribe line to list_[digest]slog). Add/remove
   aliases. Ideally, it should also allow searching by subscriber name. This
   would search *_slog.fromline. If less that 'x' alternatives are found, the
   user would be presented with names (not addresses), allowing the user to
   cause the subscription name and password to be sent to the respective
   subscription address. With that info, the subscriber can then unsubscribe,
   even if s/he has forgotten the subscription address. It is complicated
   slightly by the fact that ``fromline'' is the crude line and needs to be
   rfc822 parsed. Again, use of a standard interface is encouraged to make it
   compatible also with other SQL servers.

The aim of all this is to make it easy to use ezmlm to run very large lists,
easy to set up sites that handle subscriber interaction, archive access, etc,
and hopefully easier to integrate many ezmlm as done by some WWW sites today.

