Documents regarding the use of amavisd-new with an SQL server are located in /usr/share/doc/amavisd-new. Use gunzip to uncompress the files ending with .gz.

When amavisd-new works with an SQL server it can use two sets of tables. The first part is read only and has the following tables: users, mailaddr, wblist and policy. The second part is read/write and is used when you store quarantined emails into the SQL. The tables in the second part are: maddr, msgs, msgrcpt, quarantine.

We are going to setup both sets of tables in the same database named mail_amavis. Enter mysql and run:

CREATE DATABASE mail_amavis;
CREATE USER 'amavis'@'localhost' IDENTIFIED BY 'new_password';
GRANT ALL PRIVILEGES ON `mail_amavis` . * TO 'amavis'@'localhost';
FLUSH PRIVILEGES;

Create an amavis.sql file and paste this into it:

-- local users
CREATE TABLE users (
  id         int unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY,  -- unique id
  priority   integer      NOT NULL DEFAULT '7',  -- sort field, 0 is low prior.
  policy_id  integer unsigned NOT NULL DEFAULT '1',  -- JOINs with policy.id
  email      varbinary(255) NOT NULL UNIQUE,
  fullname   varchar(255) DEFAULT NULL,    -- not used by amavisd-new
  local      char(1)      -- Y/N  (optional field, see note further down)
);

-- any e-mail address (non- rfc2822-quoted), external or local,
-- used as senders in wblist
CREATE TABLE mailaddr (
  id         int unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY,
  priority   integer      NOT NULL DEFAULT '7',  -- 0 is low priority
  email      varbinary(255) NOT NULL UNIQUE
);

-- per-recipient whitelist and/or blacklist,
-- puts sender and recipient in relation wb  (white or blacklisted sender)
CREATE TABLE wblist (
  rid        integer unsigned NOT NULL,  -- recipient: users.id
  sid        integer unsigned NOT NULL,  -- sender: mailaddr.id
  wb         varchar(10)  NOT NULL,  -- W or Y / B or N / space=neutral / score
  PRIMARY KEY (rid,sid)
);

CREATE TABLE policy (
  id  int unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY,
                                    -- 'id' this is the _only_ required field
  policy_name      varchar(32),     -- not used by amavisd-new, a comment

  virus_lover          char(1) default NULL,     -- Y/N
  spam_lover           char(1) default NULL,     -- Y/N
  banned_files_lover   char(1) default NULL,     -- Y/N
  bad_header_lover     char(1) default NULL,     -- Y/N

  bypass_virus_checks  char(1) default NULL,     -- Y/N
  bypass_spam_checks   char(1) default NULL,     -- Y/N
  bypass_banned_checks char(1) default NULL,     -- Y/N
  bypass_header_checks char(1) default NULL,     -- Y/N

  spam_modifies_subj   char(1) default NULL,     -- Y/N

  virus_quarantine_to      varchar(64) default NULL,
  spam_quarantine_to       varchar(64) default NULL,
  banned_quarantine_to     varchar(64) default NULL,
  bad_header_quarantine_to varchar(64) default NULL,
  clean_quarantine_to      varchar(64) default NULL,
  other_quarantine_to      varchar(64) default NULL,

  spam_tag_level  float default NULL, -- higher score inserts spam info headers
  spam_tag2_level float default NULL, -- inserts 'declared spam' header fields
  spam_kill_level float default NULL, -- higher score triggers evasive actions
                                      -- e.g. reject/drop, quarantine, ...
                                     -- (subject to final_spam_destiny setting)
  spam_dsn_cutoff_level        float default NULL,
  spam_quarantine_cutoff_level float default NULL,

  addr_extension_virus      varchar(64) default NULL,
  addr_extension_spam       varchar(64) default NULL,
  addr_extension_banned     varchar(64) default NULL,
  addr_extension_bad_header varchar(64) default NULL,

  warnvirusrecip      char(1)     default NULL, -- Y/N
  warnbannedrecip     char(1)     default NULL, -- Y/N
  warnbadhrecip       char(1)     default NULL, -- Y/N
  newvirus_admin      varchar(64) default NULL,
  virus_admin         varchar(64) default NULL,
  banned_admin        varchar(64) default NULL,
  bad_header_admin    varchar(64) default NULL,
  spam_admin          varchar(64) default NULL,
  spam_subject_tag    varchar(64) default NULL,
  spam_subject_tag2   varchar(64) default NULL,
  message_size_limit  integer     default NULL, -- max size in bytes, 0 disable
  banned_rulenames    varchar(64) default NULL  -- comma-separated list of ...
        -- names mapped through %banned_rules to actual banned_filename tables
);

-- R/W part of the dataset (optional)
--   May reside in the same or in a separate database as lookups database;
--   REQUIRES SUPPORT FOR TRANSACTIONS; specified in @storage_sql_dsn
--
--  Wayne Smith adds: When using MySQL with InnoDB one might want to
--  increase buffer size for both pool and log, and might also want
--  to change flush settings for a little better performance. Example:
--    innodb_buffer_pool_size = 384M
--    innodb_log_buffer_size = 8M
--    innodb_flush_log_at_trx_commit = 0
--  The big performance increase is the first two, the third just helps with
--  lowering disk activity. Consider also adjusting the key_buffer_size.

-- provide unique id for each e-mail address, avoids storing copies
CREATE TABLE maddr (
  partition_tag integer   DEFAULT 0,   -- see $sql_partition_tag
  id         bigint unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY,
  email      varbinary(255) NOT NULL,  -- full mail address
  domain     varchar(255)   NOT NULL,  -- only domain part of the email address
                                       -- with subdomain fields in reverse
  CONSTRAINT part_email UNIQUE (partition_tag,email)
) ENGINE=InnoDB;

-- information pertaining to each processed message as a whole;
-- NOTE: records with NULL msgs.content should be ignored by utilities,
--   as such records correspond to messages just being processes, or were lost
-- NOTE: instead of a character field time_iso, one might prefer:
--   time_iso TIMESTAMP NOT NULL DEFAULT 0,
--   but the following MUST then be set in amavisd.conf: $timestamp_fmt_mysql=1
CREATE TABLE msgs (
  partition_tag integer    DEFAULT 0,   -- see $sql_partition_tag
  mail_id    varbinary(12) NOT NULL PRIMARY KEY,  -- long-term unique mail id
  secret_id  varbinary(12)   DEFAULT '',  -- authorizes release of mail_id
  am_id      varchar(20)   NOT NULL,    -- id used in the log
  time_num   integer unsigned NOT NULL, -- rx_time: seconds since Unix epoch
  time_iso   char(16)      NOT NULL,    -- rx_time: ISO8601 UTC ascii time
  sid        bigint unsigned NOT NULL, -- sender: maddr.id
  policy     varchar(255)  DEFAULT '',  -- policy bank path (like macro %p)
  client_addr varchar(255) DEFAULT '',  -- SMTP client IP address (IPv4 or v6)
  size       integer unsigned NOT NULL, -- message size in bytes
  content    binary(1),                 -- content type: V/B/S/s/M/H/O/C:
    -- virus/banned/spam(kill)/spammy(tag2)/bad-mime/bad-header/oversized/clean
    -- is NULL on partially processed mail
    -- use binary instead of char for case sensitivity ('S' != 's')
  quar_type  binary(1),                 -- quarantined as: ' '/F/Z/B/Q/M/L
                                        --  none/file/zipfile/bsmtp/sql/
                                        --  /mailbox(smtp)/mailbox(lmtp)
  quar_loc   varbinary(255) DEFAULT '', -- quarantine location (e.g. file)
  dsn_sent   char(1),                   -- was DSN sent? Y/N/q (q=quenched)
  spam_level float,                     -- SA spam level (no boosts)
  message_id varchar(255)  DEFAULT '',  -- mail Message-ID header field
  from_addr  varchar(255)  DEFAULT '',  -- mail From header field,    UTF8
  subject    varchar(255)  DEFAULT '',  -- mail Subject header field, UTF8
  host       varchar(255)  NOT NULL,    -- hostname where amavisd is running
  FOREIGN KEY (sid) REFERENCES maddr(id) ON DELETE RESTRICT
) ENGINE=InnoDB;
CREATE INDEX msgs_idx_sid      ON msgs (sid);
CREATE INDEX msgs_idx_mess_id  ON msgs (message_id); -- useful with pen pals
CREATE INDEX msgs_idx_time_num ON msgs (time_num);
-- alternatively when purging based on time_iso (instead of msgs_idx_time_num):
-- CREATE INDEX msgs_idx_time_iso ON msgs (time_iso);

-- per-recipient information related to each processed message;
-- NOTE: records in msgrcpt without corresponding msgs.mail_id record are
--  orphaned and should be ignored and eventually deleted by external utilities
CREATE TABLE msgrcpt (
  partition_tag integer    DEFAULT 0,    -- see $sql_partition_tag
  mail_id    varbinary(12) NOT NULL,     -- (must allow duplicates)
  rid        bigint unsigned NOT NULL,   -- recipient: maddr.id (dupl. allowed)
  ds         char(1)       NOT NULL,     -- delivery status: P/R/B/D/T
                                         -- pass/reject/bounce/discard/tempfail
  rs         char(1)       NOT NULL,     -- release status: initialized to ' '
  bl         char(1)       DEFAULT ' ',  -- sender blacklisted by this recip
  wl         char(1)       DEFAULT ' ',  -- sender whitelisted by this recip
  bspam_level float,                     -- spam level + per-recip boost
  smtp_resp  varchar(255)  DEFAULT '',   -- SMTP response given to MTA
  FOREIGN KEY (rid)     REFERENCES maddr(id)     ON DELETE RESTRICT,
  FOREIGN KEY (mail_id) REFERENCES msgs(mail_id) ON DELETE CASCADE
) ENGINE=InnoDB;
CREATE INDEX msgrcpt_idx_mail_id  ON msgrcpt (mail_id);
CREATE INDEX msgrcpt_idx_rid      ON msgrcpt (rid);

-- mail quarantine in SQL, enabled by $*_quarantine_method='sql:'
-- NOTE: records in quarantine without corresponding msgs.mail_id record are
--  orphaned and should be ignored and eventually deleted by external utilities
CREATE TABLE quarantine (
  partition_tag integer    DEFAULT 0,    -- see $sql_partition_tag
  mail_id    varbinary(12) NOT NULL,     -- long-term unique mail id
  chunk_ind  integer unsigned NOT NULL,  -- chunk number, starting with 1
  mail_text  blob          NOT NULL,     -- store mail as chunks of octets
  PRIMARY KEY (mail_id,chunk_ind),
  FOREIGN KEY (mail_id) REFERENCES msgs(mail_id) ON DELETE CASCADE
) ENGINE=InnoDB;

INSERT INTO policy (id, policy_name,
  virus_lover, spam_lover, banned_files_lover, bad_header_lover,
  bypass_virus_checks, bypass_spam_checks,
  bypass_banned_checks, bypass_header_checks, spam_modifies_subj,
  spam_tag_level, spam_tag2_level, spam_kill_level) VALUES
  (1, 'Non-paying',    'N','N','N','N', 'Y','Y','Y','N', 'Y', 3.0,   7, 10),
  (2, 'Uncensored',    'Y','Y','Y','Y', 'N','N','N','N', 'N', 3.0, 999, 999),
  (3, 'Wants all spam','N','Y','N','N', 'N','N','N','N', 'Y', 3.0, 999, 999),
  (4, 'Wants viruses', 'Y','N','Y','Y', 'N','N','N','N', 'Y', 3.0, 6.9, 6.9),
  (5, 'Normal',        'N','N','N','N', 'N','N','N','N', 'Y', -999, 6.9, 9.0),
  (6, 'Trigger happy', 'N','N','N','N', 'N','N','N','N', 'Y', 3.0,   5, 5),
  (7, 'Permissive',    'N','N','N','Y', 'N','N','N','N', 'Y', 3.0,  10, 20);

To run this SQL:

mysql -p mail_amavis < amavis-schema.sql

Now that we have the database set we need to reconfigure amavisd-new.

Open /etc/amavis/conf.d/50-user and add/set the the information that amavis needs to connect to the database (replace new_passwd with the password you chose for the amavis user):

@lookup_sql_dsn =  ( ['DBI:mysql:database=mail_amavis;host=127.0.0.1;port=3306', 'amavis', 'new_passwd']);
@storage_sql_dsn = @lookup_sql_dsn;

If you decided to split read and read/write parts of the amavis database you will need to set @storage_sql_dsn with the correct options.

As we mentiond before, we were using @local_domains_acl = ( ".$mydomain", "domain2.com", "domain3.org" ); to tell amavis to run spam and virus checks for mail addressed to one of this domains. This is a problem because every time we add another domain we have to edit the configuration file to add the new domain to the list of local domains.

To solve this problem we have two options. One is to just check all of the incoming mail to the system for spam and viruses regardless of the recipients domaint. We can do this by rewriting the query that amavis uses to check if the email address is local to the system:

$sql_select_policy = 'SELECT "Y" AS local, 1 AS id;

But, this is not the recommended way. I didn't even test this, so your milage may vary. The recommended way is to just insert every domain you host in the users table.

For example:

mysql> USE mail_amavis;
Database changed
INSERT INTO users VALUES ( NULL, 5, 5, '@example.com',      NULL, 'Y');

To explain what this does, first lets take a look at the users table now:

mysql> select * from users;
+----+----------+-----------+--------------+----------+-------+
| id | priority | policy_id | email        | fullname | local |
+----+----------+-----------+--------------+----------+-------+
|  1 |        5 |         5 | @example.com | NULL     | Y     |
+----+----------+-----------+--------------+----------+-------+

This raw in the table will match all email directed to any email address @example.com domain (that is because the local is set to Y). If we add another raw to the table that has email set to someuser@example.com and priority is higher than 5 this users policy will have precedance over the domains policy.

And finaly the policy_id. In this example it says that all the email directed to @example.com domain will use a policy with an identifier 5. If you take a look at the amavis-schema.sql file we used to create the database for amavis, at the end we also inserted some policies, and the policy with an ID 5 was inserted like this:

INSERT INTO policy (id, policy_name,
  virus_lover, spam_lover, banned_files_lover, bad_header_lover,
  bypass_virus_checks, bypass_spam_checks,
  bypass_banned_checks, bypass_header_checks, spam_modifies_subj,
  spam_tag_level, spam_tag2_level, spam_kill_level) VALUES
  (5, 'Normal',        'N','N','N','N', 'N','N','N','N', 'Y', -999, 6.9, 9);

We will skeep through most of the options (you have amavisd-new documentation if you want to go into detail) but we will look at the last three numbers inserted. spam_tag_level, spam_tag2_level and spam_kill_level are set to 3.0, 6.9 and 8.0 respectively. This means that emails that are flagged with over -999 (that should be all emails) by SpamAssassin will have X-Spam headers added to them. Emails tagged over 6.9 will have "SPAM" added to the subject and emails tagged over 9 will trigger spam evasive actions (depends on what you have $final_spam_destiny set to in the config file /etc/amavis/conf.d/50-user).

If you still want to set the same settings for all of the domains you can add a catchall user to the users table that will use the policy with ID 5.

INSERT INTO users VALUES (NULL, 0, 5, '@.',             NULL, 'Y');

You will have to cleanup the records in the MySQL from time to time, so we are going to create a PHP script that is going to be run daily with CRON.

#!/usr/bin/php
<?php

/**
* Amavisd-new cleanup script
* 
* Based on the Amavisd-new documentation shipped with amavisd-new package in
* Debian 6.0 (Squeeze). Version of Amavisd-new 2.6.4.
*
* @author Goran Juric
**/

$host = 'localhost';
$user = 'amavis';
$password = 'new_passwd';
$database = 'mail_amavis';
$keep_days = 14;

// Calculate the timestamp
$prune_older_then = time() - ($keep_days * 24 * 60 * 60);

// Connect to the database
$link = mysql_connect($host, $user, $password);
if (!$link) {
    die('Could not connect: ' . mysql_error());
}
$db = mysql_select_db($database, $link);
if (!$db) {
    die ("Can't use $database : " . mysql_error());
}

// Delete old msgs records based on timestamps only (for time_iso see next),
// and delete leftover msgs records from aborted mail checking operations
mysql_query("DELETE FROM msgs WHERE time_num < $prune_older_then ;", $link)
    or die(mysql_error());;
mysql_query("DELETE FROM msgs WHERE time_num < 60*60 AND content IS NULL;", $link)
    or die(mysql_error());;

// Delete unreferenced e-mail addresses
mysql_query("DELETE FROM maddr
WHERE NOT EXISTS (SELECT 1 FROM msgs WHERE sid=id)
AND NOT EXISTS (SELECT 1 FROM msgrcpt WHERE rid=id);", $link)
    or die(mysql_error());;

// When a FOREIGN KEY ... ON DELETE CASCADE is not used, tables msgrcpt
// and quarantine need to be purged explicitly, e.g.:
mysql_query("DELETE FROM quarantine
WHERE NOT EXISTS (SELECT 1 FROM msgs WHERE mail_id=quarantine.mail_id);", $link)
    or die(mysql_error());;
mysql_query("DELETE FROM msgrcpt
WHERE NOT EXISTS (SELECT 1 FROM msgs WHERE mail_id=msgrcpt.mail_id);", $link)
    or die(mysql_error());;

// Optimize tables
mysql_query("OPTIMIZE TABLE msgs, msgrcpt, quarantine, maddr;", $link)
    or die(mysql_error());;

// Close the database
mysql_close($link);

Save this file to /etc/cron.daily/amavisd-new-cleanup (change the password at the top of the file) and make the script executable:

chmod +x /etc/cron.daily/amavisd-new-cleanup
chmod 700 /etc/cron.daily/amavisd-new-cleanup

If you want a GUI for managing your Amavisd-new configuration take a look at Postvis Admin.