<b><a name="description">DESCRIPTION</a></b>
The Postfix mail system uses optional tables for address rewriting or
mail routing. These tables are usually in <b><a href="lmdb_table.5.html">lmdb</a>:</b>, <b><a href="CDB_README.html">cdb</a>:</b>, <b><a href="DATABASE_README.html#types">hash</a>:</b>, or <b><a href="DATABASE_README.html#types">dbm</a>:</b>
format.
Alternatively, lookup tables can be specified as PostgreSQL databases.
To find out what types of lookup tables your Postfix system supports
use the "<b>postconf -m</b>"command.
In order to use PostgreSQL lookups, define a PostgreSQL source as a
lookup table in <a href="postconf.5.html">main.cf</a>, for example:
<a href="postconf.5.html#alias_maps">alias_maps</a> = <a href="pgsql_table.5.html">pgsql</a>:/etc/postfix/pgsql-aliases.cf
The file /etc/postfix/pgsql-aliases.cf has the same format as the Post-
fix <a href="postconf.5.html">main.cf</a> file, and can specify the parameters described below.
<b><a name="list_membership">LIST MEMBERSHIP</a></b>
When using SQL to store lists such as $<a href="postconf.5.html#mynetworks">mynetworks</a>, $<ahref="postconf.5.html#mydestination">mydestination</a>,
$<a href="postconf.5.html#relay_domains">relay_domains</a>, $<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a>, etc., it is important to under-
stand that the table must store each list member as a separate key. The table lookup verifies the *existence* of the key. See "Postfix lists
versus tables" in the <a href="DATABASE_README.html">DATABASE_README</a> document for a discussion.
Do NOT create tables that return the full list of domains in $<a href="postconf.5.html#mydestination">mydesti</a>-
<a href="postconf.5.html#mydestination">nation</a> or $<a href="postconf.5.html#relay_domains">relay_domains</a> etc., or IP addresses in $<a href="postconf.5.html#mynetworks">mynetworks</a>.
DO create tables with each matching item as a key and with an arbitrary
value. With SQL databases it is not uncommon to return the key itself
or a constant value.
<b><a name="pgsql_parameters">PGSQL PARAMETERS</a></b>
<b>hosts</b> The hosts that Postfix will try to connect to and query from.
Besides a PostgreSQL connection URI, this setting supports the
historical forms <b>unix:/</b><i>pathname</i> for UNIX-domain sockets and
<b>inet:</b><i>host:port</i> for TCP connections, where the <b>unix:</b> and <b>inet:</b>
prefixes are accepted and ignored for backwards compatibility.
Examples:
hosts = postgresql://username@example.com/<i>databasename</i>?sslmode=require
hosts = postgres://user:secret@localhost
hosts = inet:host1.some.domain inet:host2.some.domain:port
hosts = host1.some.domain host2.some.domain:port
hosts = unix:/file/name
The hosts are tried in random order. The connections are auto-
matically closed after being idle for about 1 minute, and are
re-opened as necessary. See <b>idle_interval</b> for details.
NOTE: if the <b>hosts</b> setting specifies a PostgreSQL connection
URI, the Postfix PostgreSQL client will ignore the <b>dbname</b>, <b>user</b>,
and <b>password</b> settings for that connection.
NOTE: if the <b>hosts</b> setting specifies only one server, this
client assumes that the target is a load balancer and will
reconnect immediately after a single failure. With Postfix ver-
sions 3.9 and earlier, specify the same server twice.
<b>user</b>
<b>password</b>
The user name and password to log into the pgsql server. Exam-
ple:
user = someone
password = some_password
The <b>user</b> and <b>password</b> settings are ignored for <b>hosts</b> connections
that are specified as an URI.
<b>dbname</b> The database name on the servers. Example:
dbname = customer_database
The <b>dbname</b> setting is ignored for <b>hosts</b> connections that are
specified as an URI.
The <b>dbname</b> setting is required with Postfix 3.10 and later, when
<b>hosts</b> specifies any non-URI connection; it is always required
with earlier Postfix versions.
<b>encoding</b>
The encoding used by the database client. The default setting
is:
encoding = UTF8
Historically, the database client was hard coded to use LATIN1
in an attempt to disable multibyte character support.
This feature is available in Postfix 3.8 and later.
<b>idle_interval (default: 60)</b>
The number of seconds after which an idle database connection
will be closed.
This feature is available in Postfix 3.9 and later.
<b>retry_interval (default: 60)</b>
The number of seconds that a database connection will be skipped
after an error.
NOTE: if the <b>hosts</b> setting specifies only one server, this
client assumes that the target is a load balancer and will
reconnect immediately after a single failure. With Postfix ver-
sions 3.9 and earlier, specify the same server twice.
This feature is available in Postfix 3.9 and later.
<b>query</b> The SQL query template used to search the database, where <b>%s</b> is a substitute for the address Postfix is trying to resolve, e.g.
query = SELECT replacement FROM aliases WHERE mailbox = '%s'
This parameter supports the following '%' expansions:
<b>%%</b> This is replaced by a literal '%' character. (Postfix 2.2
and later)
<b>%s</b> This is replaced by the input key. SQL quoting is used
to make sure that the input key does not add unexpected
metacharacters.
<b>%u</b> When the input key is an address of the form user@domain,
<b>%u</b> is replaced by the SQL quoted local part of the address. Otherwise, <b>%u</b> is replaced by the entire search
string. If the localpart is empty, the query is sup-
pressed and returns no results.
<b>%d</b> When the input key is an address of the form user@domain,
<b>%d</b> is replaced by the SQL quoted domain part of the address. Otherwise, the query is suppressed and returns
no results.
<b>%[SUD]</b> The upper-case equivalents of the above expansions behave
in the <b>query</b> parameter identically to their lower-case
counter-parts. With the <b>result_format</b> parameter (see
below), they expand the input key rather than the result
value.
The above %S, %U and %D expansions are available with
Postfix 2.2 and later
<b>%[1-9]</b> The patterns %1, %2, ... %9 are replaced by the corre-
sponding most significant component of the input key's
domain. If the input key is <i>user@mail.example.com</i>, then
%1 is <b>com</b>, %2 is <b>example</b> and %3 is <b>mail</b>. If the input key
is unqualified or does not have enough domain components
to satisfy all the specified patterns, the query is sup-
pressed and returns no results.
The above %1, ... %9 expansions are available with Post-
fix 2.2 and later
The <b>domain</b> parameter described below limits the input keys to
addresses in matching domains. When the <b>domain</b> parameter is
non-empty, SQL queries for unqualified addresses or addresses in
non-matching domains are suppressed and return no results.
The precedence of this parameter has changed with Postfix 2.2,
in prior releases the precedence was, from highest to lowest,
<b>select_function</b>, <b>query</b>, <b>select_field</b>, ...
With Postfix 2.2 the <b>query</b> parameter has highest precedence, see
OBSOLETE QUERY INTERFACES below.
NOTE: DO NOT put quotes around the <b>query</b> parameter.
<b>result_format (default: %s</b>)
Format template applied to result attributes. Most commonly used
to append (or prepend) text to the result. This parameter sup-
ports the following '%' expansions:
<b>%%</b> This is replaced by a literal '%' character.
<b>%s</b> This is replaced by the value of the result attribute.
When result is empty it is skipped.
<b>%u</b> When the result attribute value is an address of the form
user@domain, <b>%u</b> is replaced by the local part of the address. When the result has an empty localpart it is
skipped.
<b>%d</b> When a result attribute value is an address of the form
user@domain, <b>%d</b> is replaced by the domain part of the
attribute value. When the result is unqualified it is
skipped.
<b>%[SUD1-9]</b>
The upper-case and decimal digit expansions interpolate
the parts of the input key rather than the result. Their
behavior is identical to that described with <b>query</b>, and
in fact because the input key is known in advance,
queries whose key does not contain all the information
specified in the result template are suppressed and
return no results.
For example, using "result_format = <a href="smtp.8.html">smtp</a>:[%s]" allows one to use a mailHost attribute as the basis of a <a href="transport.5.html">transport(5)</a> table. After
applying the result format, multiple values are concatenated as
comma separated strings. The expansion_limit and parameter
explained below allows one to restrict the number of values in
the result, which is especially useful for maps that must return
at most one value.
The default value <b>%s</b> specifies that each result value should be
used as is.
This parameter is available with Postfix 2.2 and later.
NOTE: DO NOT put quotes around the result format!
<b>domain (default: no domain list)</b>
This is a list of domain names, paths to files, or "<a href="DATABASE_README.html">type:table</a>"
databases. When specified, only fully qualified search keys with a *non-empty* localpart and a matching domain are eligible for
lookup: 'user' lookups, bare domain lookups and "@domain"
lookups are not performed. This can significantly reduce the
query load on the PostgreSQL server.
domain = postfix.org, <a href="DATABASE_README.html#types">hash</a>:/etc/postfix/searchdomains
It is best not to use SQL to store the domains eligible for SQL
lookups.
This parameter is available with Postfix 2.2 and later.
NOTE: DO NOT define this parameter for <a href="local.8.html">local(8)</a> aliases, because
the input keys are always unqualified.
<b>expansion_limit (default: 0)</b>
A limit on the total number of result elements returned (as a
comma separated list) by a lookup against the map. A setting of
zero disables the limit. Lookups fail with a temporary error if
the limit is exceeded. Setting the limit to 1 ensures that
lookups do not return multiple values.
<b>OBSOLETE MAIN.CF PARAMETERS</b>
For compatibility with other Postfix lookup tables, PostgreSQL parame-
ters can also be defined in <a href="postconf.5.html">main.cf</a>. In order to do that, specify as
PostgreSQL sourcea name that doesn't begin with a slash or a dot. The
PostgreSQL parameters will then be accessible as the name you've given
the source in its definition, an underscore, and the name of the param-
eter. For example, if the map is specified as "<a href="pgsql_table.5.html">pgsql</a>:<i>pgsqlname</i>", the
parameter "hosts" would be defined in <a href="postconf.5.html">main.cf</a> as "<i>pgsqlname</i>_hosts".
Note: with this form, the passwords for the PostgreSQL sources are
written in <a href="postconf.5.html">main.cf</a>, which is normally world-readable. Support for this form will be removed in a future Postfix version.
<b><a name="obsolete_query_interfaces">OBSOLETE QUERY INTERFACES</a></b>
This section describes query interfaces that are deprecated as of Post-
fix 2.2. Please migrate to the new <b>query</b> interface as the old inter-
faces are slated to be phased out.
<b>select_function</b>
This parameter specifies a database function name. Example:
select_function = my_lookup_user_alias
This is equivalent to:
query = SELECT my_lookup_user_alias('%s')
This parameter overrides the legacy table-related fields
(described below). With Postfix versions prior to 2.2, it also
overrides the <b>query</b> parameter. Starting with Postfix 2.2, the
<b>query</b> parameter has highest precedence, and the <b>select_function</b>
parameter is deprecated.
The following parameters (with lower precedence than the <b>select_func-</b>
<b>tion</b> interface described above) can be used to build the SQL select
statement as follows:
SELECT [<b>select_field</b>]
FROM [<b>table</b>]
WHERE [<b>where_field</b>] = '%s'
[<b>additional_conditions</b>]
The specifier %s is replaced with each lookup by the lookup key and is
escaped so if it contains single quotes or other odd characters, it
will not cause a parse error, or worse, a security problem.
Starting with Postfix 2.2, this interface is obsoleted by the more gen-
eral <b>query</b> interface described above. If higher precedence the <b>query</b> or
<b>select_function</b> parameters described above are defined, the parameters
described here are ignored.
<b>select_field</b>
The SQL "select" parameter. Example:
<b>select_field</b> = forw_addr
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