From: Wietse Venema <wietse@porcupine.org>
Date: Fri, 15 Mar 2013 05:00:00 +0000 (-0500)
Subject: postfix-2.11-20130315
X-Git-Tag: v2.11.0-RC1~52
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e24ec95ab0cf59900da5e878b1875351c5389156;p=thirdparty%2Fpostfix.git

postfix-2.11-20130315
---

diff --git a/postfix/.indent.pro b/postfix/.indent.pro
index 204f673d7..41daed59e 100644
--- a/postfix/.indent.pro
+++ b/postfix/.indent.pro
@@ -72,6 +72,7 @@
 -TDICT_FAIL
 -TDICT_HT
 -TDICT_LDAP
+-TDICT_LMDB
 -TDICT_MC
 -TDICT_MYSQL
 -TDICT_NI
diff --git a/postfix/HISTORY b/postfix/HISTORY
index 1793ebebb..d0d817ed3 100644
--- a/postfix/HISTORY
+++ b/postfix/HISTORY
@@ -18247,3 +18247,13 @@ Apologies for any names omitted.
 
 	Bugfix: an error handler for smtp_tls_policy_maps lookups
 	was never invoked.  File: smtp/smtp_session.c.
+
+20130315
+
+	Feature: preliminary LMDB (memory-mapped persistent file)
+	support by Howard Chu. This feature has a number of unexpected
+	limitations and is therefore "snapshot only", i.e. it will
+	not be part of a stable release.  Files: proto/postconf.proto,
+	proto/LMDB_README.html, proto/DATABASE_README.html,
+	util/dict_lmdb.[hc], util/dict_open.c, global/mkmap_lmdb.[hc],
+	global/mkmap_open.c, postconf/postconf.c.
diff --git a/postfix/README_FILES/DATABASE_README b/postfix/README_FILES/DATABASE_README
index 79181be35..ceb661b7d 100644
--- a/postfix/README_FILES/DATABASE_README
+++ b/postfix/README_FILES/DATABASE_README
@@ -210,6 +210,12 @@ To find out what database types your Postfix system supports, use the "ppooss
     iinntteerrnnaall
         A non-shared, in-memory hash table. Its content are lost when a process
         terminates.
+    llmmddbb
+        The OpenLDAP LMDB database (a memory-mapped, persistent file). Database
+        files are created with the postmap(1) or postalias(1) command. The
+        database name as used in "lmdb:table" is the database file name without
+        the ".lmdb" suffix. This database type has unexpected limitations and
+        is therefore not part of the stable Postfix release.
     llddaapp (read-only)
         Perform lookups using the LDAP protocol. Configuration details are
         given in the ldap_table(5).
diff --git a/postfix/README_FILES/INSTALL b/postfix/README_FILES/INSTALL
index 2ab58b4e9..9ed6a0541 100644
--- a/postfix/README_FILES/INSTALL
+++ b/postfix/README_FILES/INSTALL
@@ -148,18 +148,20 @@ compiler. Here are a few examples:
 
 and so on. In some cases, optimization is turned off automatically.
 
-44..33 -- BBuuiillddiinngg wwiitthh ooppttiioonnaall eexxtteennssiioonnss
+44..33 -- BBuuiillddiinngg wwiitthh ooppttiioonnaall ffeeaattuurreess
 
 By default, Postfix builds as a mail system with relatively few bells and
 whistles. Support for third-party databases etc. must be configured when
 Postfix is compiled. The following documents describe how to build Postfix with
-support for extensions:
+support for optional features:
 
      _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
-    |PPoossttffiixx eexxtteennssiioonn                 |DDooccuummeenntt     |AAvvaaiillaabbiilliittyy|
+    |OOppttiioonnaall ffeeaattuurree                  |DDooccuummeenntt     |AAvvaaiillaabbiilliittyy|
     |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ |
     |Berkeley DB database              |DB_README    |Postfix 1.0 |
     |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ |
+    |LMDB database                     |LMDB_README  |Postfix 2.11|
+    |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ |
     |LDAP database                     |LDAP_README  |Postfix 1.0 |
     |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ |
     |MySQL database                    |MYSQL_README |Postfix 1.0 |
diff --git a/postfix/README_FILES/LMDB_README b/postfix/README_FILES/LMDB_README
new file mode 100644
index 000000000..7d422e0a3
--- /dev/null
+++ b/postfix/README_FILES/LMDB_README
@@ -0,0 +1,125 @@
+PPoossttffiixx OOppeennLLDDAAPP LLMMDDBB HHoowwttoo
+
+-------------------------------------------------------------------------------
+
+IInnttrroodduuccttiioonn
+
+Postfix uses databases of various kinds to store and look up information.
+Postfix databases are specified as "type:name". OpenLDAP LMDB implements the
+Postfix database type "lmdb". The name of a Postfix OpenLDAP LMDB database is
+the name of the database file without the ".lmdb" suffix. OpenLDAP LMDB
+databases are maintained with the postmap(1) command.
+
+This document describes:
+
+ 1. How to build Postfix with OpenLDAP LMDB support.
+
+ 2. How to configure LMDB settings.
+
+ 3. Missing pthread library trouble.
+
+    Caution: the current Postfix LMDB client has unexpected limitations. For
+    this reason, LMDB support is not part of the stable Postfix release.
+
+BBuuiillddiinngg PPoossttffiixx wwiitthh OOppeennLLDDAAPP LLMMDDBB ssuuppppoorrtt
+
+Postfix normally does not enable OpenLDAP LMDB support. To build Postfix after
+you installed OpenLDAP LMDB from source code, use something like:
+
+    % make makefiles CCARGS="-DHAS_LMDB -I/usr/local/include" \
+        AUXLIBS="-L/usr/local/lib -llmdb"
+    % make
+
+Solaris needs this:
+
+    % make makefiles CCARGS="-DHAS_LMDB -I/usr/local/include" \
+        AUXLIBS="-R/usr/local/lib -L/usr/local/lib -llmdb"
+    % make
+
+The exact pathnames depend on how OpenLDAP LMDB was installed.
+
+CCoonnffiigguurree LLMMDDBB sseettttiinnggss
+
+Postfix provides a configuration parameter that controls how large an OpenLDAP
+LMDB database may grow.
+
+  * lmdb_map_size (default: 10 MBytes per table). This setting controls how
+    large any OpenLDAP LMDB database may grow. It must be set large enough to
+    accommodate the largest table that Postfix will use.
+
+MMiissssiinngg pptthhrreeaadd lliibbrraarryy ttrroouubbllee
+
+When building Postfix fails with:
+
+    undefined reference to `pthread_mutexattr_destroy'
+    undefined reference to `pthread_mutexattr_init'
+    undefined reference to `pthread_mutex_lock'
+
+Add the "-lpthread" library to the "make makefiles" command.
+
+    % make makefiles .... AUXLIBS="... -lpthread"
+
+Source code for OpenLDAP LMDB is available at http://www.openldap.org. More
+information is available at http://highlandsun.com/hyc/mdb/.
+
+LLiimmiittaattiioonnss ooff PPoossttffiixx LLMMDDBB ddaattaabbaasseess..
+
+  * UUnneexxppeecctteedd ppoossttmmaapp//ppoossttaalliiaass ""ddaattaabbaassee ffuullll"" eerrrroorrss..
+
+    Even if the "postmap filename" command succeeds, the exact same command,
+    with the exact same input data, may fail subsequently with an MDB_MAP_FULL
+    error. The reason is that unlike other Postfix databases such as "hash" or
+    "btree",
+
+      o LMDB databases have a hard size limit (configured with the
+        lmdb_map_size configuration parameter).
+
+      o The Postfix LMDB database client does not implement the "truncate"
+        operation. Instead it saves all store requests to a transaction (which
+        takes up space in addition to the existing data), and commits the
+        transaction when the database is closed. Only then can the space for
+        old data be reused.
+
+    This postmap(1) or postalias(1) command failure does not affect Postfix
+    availability, because the old data still exists in the database.
+
+    To recover, increase the lmdb_map_size limit in main.cf, and retry the
+    postmap(1) or postalias(1) command.
+
+  * PPoossttffiixx ddaaeemmoonn ""ddaattaabbaassee ffuullll"" eerrrroorrss..
+
+    Unfortunately, "database full" problems will affect Postfix availability
+    with daemon programs such as postscreen(8), tlsmgr(8) or verify(8). These
+    daemon programs will continue to fail until someone increases the
+    lmdb_map_size parameter value. Meanwhile, mail processing comes to a halt.
+
+  * NNoonn--oobbvviioouuss rreeccoovveerryy ffrroomm aa ccoorrrruupptteedd ddaattaabbaassee..
+
+    Unlike other Postfix databases such as "hash" or "btree", you can't rebuild
+    a corrupted LMDB database simply by running postmap(1) or postalias(1), as
+    those commands will crash, too.
+
+    The reason for this limitation is that the Postfix LMDB database client
+    does not implement the database "truncate" operation. Instead it tries to
+    save all store requests to a transaction for later processing. That is
+    obviously not possible with a corrupted database file.
+
+    To recover, you must first delete the ".lmdb" file by hand, and only then
+    you can retry the postmap(1) or postalias(1) command.
+
+  * IInnccoommppaattiibbiilliittyy wwiitthh ttllssmmggrr((88))..
+
+    The Postfix LMDB database client breaks tlsmgr(8) TLS session cache
+    management. Specifically, it breaks how tlsmgr(8) clears its TLS session
+    cache databases upon start-up, it breaks how tlsmgr(8) looks up new TLS
+    session cache entries, and it breaks how tlsmgr(8) automatically recovers
+    from a corrupted database file.
+
+    The reason for these limitations is that the Postfix LMDB database client
+    does not implement the database "truncate" operation. Instead it saves all
+    store requests to a transaction which it commits only when the database is
+    closed. Therefore, tlsmgr(8) will never find any entries that it stores
+    after opening its TLS session cache databases. And when the database
+    becomes corrupted, tlsmgr(8) will keep crashing until someone removes the
+    file ".lmdb" file by hand.
+
diff --git a/postfix/RELEASE_NOTES b/postfix/RELEASE_NOTES
index 41818732b..94a1a46ea 100644
--- a/postfix/RELEASE_NOTES
+++ b/postfix/RELEASE_NOTES
@@ -13,3 +13,11 @@ specifies the release date of a stable release or snapshot release.
 
 If you upgrade from Postfix 2.9 or earlier, read RELEASE_NOTES-2.10
 before proceeding.
+
+Major changes with snapshot 20130315
+====================================
+
+Perliminary LMDB support by Howard Chu. This implementation has
+unexpected limitations that make it a poor fit, and for this reason
+the code is "snapshot only", i.e. it will not be part of the stable
+release. See LMDB_README for details.
diff --git a/postfix/html/DATABASE_README.html b/postfix/html/DATABASE_README.html
index bf1447b01..0c1169d99 100644
--- a/postfix/html/DATABASE_README.html
+++ b/postfix/html/DATABASE_README.html
@@ -311,6 +311,15 @@ name as used in "hash:table" is the database file name without the
 <dd> A non-shared, in-memory hash table. Its content are lost when
 a process terminates. </dd>
 
+<dt> <b>lmdb</b> </dt>
+
+<dd> The OpenLDAP LMDB database (a memory-mapped, persistent file).
+Database files are created with the <a href="postmap.1.html">postmap(1)</a> or <a href="postalias.1.html">postalias(1)</a>
+command. The database name as used in "<a href="LMDB_README.html">lmdb</a>:table" is the database
+file name without the ".lmdb" suffix. This database type has
+unexpected limitations and is therefore not part of the stable
+Postfix release.
+
 <dt> <b>ldap</b> (read-only) </dt>
 
 <dd> Perform lookups using the LDAP protocol. Configuration details
diff --git a/postfix/html/INSTALL.html b/postfix/html/INSTALL.html
index 9356d7817..d4fd3a287 100644
--- a/postfix/html/INSTALL.html
+++ b/postfix/html/INSTALL.html
@@ -229,21 +229,25 @@ $ make
 
 <p> and so on. In some cases, optimization is turned off automatically. </p>
 
-<h3>4.3 - Building with optional extensions</h3>
+<h3>4.3 - Building with optional features</h3>
 
 By default, Postfix builds as a mail system with relatively few
 bells and whistles. Support for third-party databases etc.
-must be configured when Postfix is compiled.  The following documents describe how to build Postfix with support for extensions:
+must be configured when Postfix is compiled.  The following documents
+describe how to build Postfix with support for optional features:
 
 <blockquote>
 <table border="1">
 
-<tr> <th>Postfix extension </th> <th>Document </th> <th>Availability</th>
+<tr> <th>Optional feature </th> <th>Document </th> <th>Availability</th>
 </tr>
 
 <tr> <td> Berkeley DB database</td> <td><a href="DB_README.html">DB_README</a></td> <td> Postfix
 1.0 </td> </tr>
 
+<tr> <td> LMDB database</td> <td><a href="LMDB_README.html">LMDB_README</a></td> <td> Postfix
+2.11 </td> </tr>
+
 <tr> <td> LDAP database</td> <td><a href="LDAP_README.html">LDAP_README</a></td> <td> Postfix
 1.0 </td> </tr>
 
diff --git a/postfix/html/LMDB_README.html b/postfix/html/LMDB_README.html
new file mode 100644
index 000000000..df4e32d83
--- /dev/null
+++ b/postfix/html/LMDB_README.html
@@ -0,0 +1,190 @@
+<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN"
+        "http://www.w3.org/TR/html4/loose.dtd">
+
+<html>
+
+<head>
+
+<title>Postfix OpenLDAP LMDB Howto</title>
+
+<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
+
+</head>
+
+<body>
+
+<h1><img src="postfix-logo.jpg" width="203" height="98" ALT="">Postfix OpenLDAP LMDB Howto</h1>
+
+<hr>
+
+<h2>Introduction</h2>
+
+<p> Postfix uses databases of various kinds to store and look up
+information. Postfix databases are specified as "type:name".
+OpenLDAP LMDB implements the Postfix database type "lmdb".
+The name of a Postfix OpenLDAP LMDB database is the name
+of the database file without the ".lmdb" suffix. OpenLDAP LMDB databases
+are maintained with the <a href="postmap.1.html">postmap(1)</a> command.  </p>
+
+<p> This document describes: </p>
+
+<ol>
+
+<li> <p> How to build Postfix <a href="#with_lmdb">with OpenLDAP
+LMDB support</a>. </p>
+
+<li> <p> How to <a href="#configure">configure</a> LMDB settings. </p>
+
+<li> <p> Missing <a href="#pthread">pthread</a> library trouble. </p>
+
+</ol>
+
+<blockquote> <p> Caution: the current Postfix LMDB client has <a
+href="#limitations">unexpected limitations</a>. For this reason,
+LMDB support is not part of the stable Postfix release. </p>
+</blockquote>
+
+<h2><a name="with_lmdb">Building Postfix with OpenLDAP LMDB support</a></h2>
+
+<p> Postfix normally does not enable OpenLDAP LMDB support.
+To build Postfix after you installed OpenLDAP LMDB from
+source code, use something like: </p>
+
+<blockquote>
+<pre>
+% make makefiles CCARGS="-DHAS_LMDB -I/usr/local/include" \
+    AUXLIBS="-L/usr/local/lib -llmdb"
+% make
+</pre>
+</blockquote>
+
+<p> Solaris needs this: </p>
+
+<blockquote>
+<pre>
+% make makefiles CCARGS="-DHAS_LMDB -I/usr/local/include" \
+    AUXLIBS="-R/usr/local/lib -L/usr/local/lib -llmdb"
+% make
+</pre>
+</blockquote>
+
+<p> The exact pathnames depend on how OpenLDAP LMDB was installed. </p>
+
+<h2><a name="configure">Configure LMDB settings</a></h2>
+
+<p> Postfix provides a configuration parameter that controls how
+large an OpenLDAP LMDB database may grow. </p>
+
+<ul>
+
+<li> <p> <a href="postconf.5.html#lmdb_map_size">lmdb_map_size</a> (default: 10 MBytes per
+table).  This setting controls how large any OpenLDAP LMDB database
+may grow. It must be set large enough to accommodate the largest
+table that Postfix will use. </p>
+
+</ul>
+
+<h2><a name="pthread">Missing pthread library trouble</a></h2>
+
+<p> When building Postfix fails with: </p>
+
+<blockquote>
+<pre>
+undefined reference to `pthread_mutexattr_destroy'
+undefined reference to `pthread_mutexattr_init'
+undefined reference to `pthread_mutex_lock'
+</pre>
+</blockquote>
+
+<p> Add the "-lpthread" library to the "make makefiles" command. </p>
+
+<blockquote>
+<pre>
+% make makefiles .... AUXLIBS="... -lpthread"
+</pre>
+</blockquote>
+
+<p> Source code for OpenLDAP LMDB is available at
+<a href="http://www.openldap.org">http://www.openldap.org</a>.
+More information is available at
+<a href="http://highlandsun.com/hyc/mdb/">http://highlandsun.com/hyc/mdb/</a>. </p>
+
+<h2><a name="limitations">Limitations of Postfix LMDB databases. </a> </h2>
+
+<ul>
+
+<li> <p> <strong>Unexpected postmap/postalias "database full" errors.
+</strong></p>
+
+<p> Even if the "postmap filename" command succeeds, the exact same
+command, with the exact same input data, may fail subsequently with
+an MDB_MAP_FULL error. The reason is that unlike other Postfix
+databases such as "hash" or "btree", </p>
+
+<ul>
+
+<li> <p> LMDB databases have a hard size limit (configured with the
+<a href="postconf.5.html#lmdb_map_size">lmdb_map_size</a> configuration parameter). </p>
+
+<li> <p> The Postfix LMDB database client does not implement the
+"truncate" operation.  Instead it saves all store requests to a
+transaction (which takes up space in addition to the existing data),
+and commits the transaction when the database is closed.  Only then
+can the space for old data be reused.  </p>
+
+</ul>
+
+<p> This <a href="postmap.1.html">postmap(1)</a> or <a href="postalias.1.html">postalias(1)</a> command failure does not affect
+Postfix availability, because the old data still exists in the
+database. </p>
+
+<p> To recover, increase the <a href="postconf.5.html#lmdb_map_size">lmdb_map_size</a> limit in <a href="postconf.5.html">main.cf</a>, and
+retry the <a href="postmap.1.html">postmap(1)</a> or <a href="postalias.1.html">postalias(1)</a> command.  </p>
+
+<li> <p> <strong>Postfix daemon "database full" errors. </strong></p>
+
+<p> Unfortunately, "database full" problems will affect Postfix
+availability with daemon programs such as <a href="postscreen.8.html">postscreen(8)</a>, <a href="tlsmgr.8.html">tlsmgr(8)</a>
+or <a href="verify.8.html">verify(8)</a>. These daemon programs will continue to fail until
+someone increases the <a href="postconf.5.html#lmdb_map_size">lmdb_map_size</a> parameter value. Meanwhile,
+mail processing comes to a halt. </p>
+
+<li> <p> <strong>Non-obvious recovery from a corrupted database.
+</strong></p>
+
+<p> Unlike other Postfix databases such as "hash" or "btree", you
+can't rebuild a corrupted LMDB database simply by running <a href="postmap.1.html">postmap(1)</a>
+or <a href="postalias.1.html">postalias(1)</a>, as those commands will crash, too. </p>
+
+<p> The reason for this limitation is that the Postfix LMDB database
+client does not implement the database "truncate" operation.  Instead
+it tries to save all store requests to a transaction for later
+processing.  That is obviously not possible with a corrupted database
+file. </p>
+
+<p> To recover, you must first delete the ".lmdb" file by hand, and
+only then you can retry the <a href="postmap.1.html">postmap(1)</a> or <a href="postalias.1.html">postalias(1)</a> command.
+</p>
+
+<li> <p> <strong>Incompatibility with <a href="tlsmgr.8.html">tlsmgr(8)</a>. </strong></p>
+
+<p> The Postfix LMDB database client breaks <a href="tlsmgr.8.html">tlsmgr(8)</a> TLS session
+cache management. Specifically, it breaks how <a href="tlsmgr.8.html">tlsmgr(8)</a> clears its
+TLS session cache databases upon start-up, it breaks how <a href="tlsmgr.8.html">tlsmgr(8)</a>
+looks up new TLS session cache entries, and it breaks how <a href="tlsmgr.8.html">tlsmgr(8)</a>
+automatically recovers from a corrupted database file.  <p>
+
+<p> The reason for these limitations is that the Postfix LMDB
+database client does not implement the database "truncate" operation.
+Instead it saves all store requests to a transaction which it commits
+only when the database is closed. Therefore, <a href="tlsmgr.8.html">tlsmgr(8)</a> will never
+find any entries that it stores after opening its TLS session cache
+databases. And when the database becomes corrupted, <a href="tlsmgr.8.html">tlsmgr(8)</a> will
+keep crashing until someone removes the file ".lmdb" file by hand.
+</p>
+
+</ul>
+
+</body>
+
+</html>
diff --git a/postfix/html/postconf.5.html b/postfix/html/postconf.5.html
index 0a8a9cf91..562f34e51 100644
--- a/postfix/html/postconf.5.html
+++ b/postfix/html/postconf.5.html
@@ -3773,6 +3773,21 @@ This feature is available in Postfix 2.1 and later.
 this length; upon delivery, long lines are reconstructed.  </p>
 
 
+</DD>
+
+<DT><b><a name="lmdb_map_size">lmdb_map_size</a>
+(default: 10485760)</b></DT><DD>
+
+<p>
+The per-table size limit for programs that create OpenLDAP LMDB
+tables.  Specify a byte count.
+</p>
+
+<p>
+This feature is available in Postfix 2.11 and later.
+</p>
+
+
 </DD>
 
 <DT><b><a name="lmtp_address_preference">lmtp_address_preference</a>
diff --git a/postfix/man/man5/postconf.5 b/postfix/man/man5/postconf.5
index 9e1b3e9bb..f9706e676 100644
--- a/postfix/man/man5/postconf.5
+++ b/postfix/man/man5/postconf.5
@@ -2236,6 +2236,11 @@ This feature is available in Postfix 2.1 and later.
 .SH line_length_limit (default: 2048)
 Upon input, long lines are chopped up into pieces of at most
 this length; upon delivery, long lines are reconstructed.
+.SH lmdb_map_size (default: 10485760)
+The per-table size limit for programs that create OpenLDAP LMDB
+tables.  Specify a byte count.
+.PP
+This feature is available in Postfix 2.11 and later.
 .SH lmtp_address_preference (default: ipv6)
 The LMTP-specific version of the smtp_address_preference
 configuration parameter.  See there for details.
diff --git a/postfix/mantools/postlink b/postfix/mantools/postlink
index 151866be1..e2a54e2f0 100755
--- a/postfix/mantools/postlink
+++ b/postfix/mantools/postlink
@@ -208,6 +208,7 @@ while (<>) {
     s;\bipc_timeout\b;<a href="postconf.5.html#ipc_timeout">$&</a>;g;
     s;\bipc_ttl\b;<a href="postconf.5.html#ipc_ttl">$&</a>;g;
     s;\bline_length_limit\b;<a href="postconf.5.html#line_length_limit">$&</a>;g;
+    s;\blmdb_map_size\b;<a href="postconf.5.html#lmdb_map_size">$&</a>;g;
     s;\blmtp_bind_address\b;<a href="postconf.5.html#lmtp_bind_address">$&</a>;g;
     s;\blmtp_bind_address6\b;<a href="postconf.5.html#lmtp_bind_address6">$&</a>;g;
     s;\blmtp_assume_final\b;<a href="postconf.5.html#lmtp_assume_final">$&</a>;g;
@@ -1068,6 +1069,7 @@ while (<>) {
     s/\b(mysql):/<a href="mysql_table.5.html">$1<\/a>:/g;
     s/\b(nisplus):/<a href="nisplus_table.5.html">$1<\/a>:/g;
     s/\b(ldap):/<a href="ldap_table.5.html">$1<\/a>:/g;
+    s/\b(lmdb):/<a href="LMDB_README.html">$1<\/a>:/g;
     s/\b(regexp):/<a href="regexp_table.5.html">$1<\/a>:/g;
     s/\b(sqlite):/<a href="sqlite_table.5.html">$1<\/a>:/g;
     s/\b(static):/<a href="DATABASE_README.html#types">$1<\/a>:/g;
diff --git a/postfix/proto/DATABASE_README.html b/postfix/proto/DATABASE_README.html
index f19bf3124..0de4f55a2 100644
--- a/postfix/proto/DATABASE_README.html
+++ b/postfix/proto/DATABASE_README.html
@@ -311,6 +311,15 @@ name as used in "hash:table" is the database file name without the
 <dd> A non-shared, in-memory hash table. Its content are lost when
 a process terminates. </dd>
 
+<dt> <b>lmdb</b> </dt>
+
+<dd> The OpenLDAP LMDB database (a memory-mapped, persistent file).
+Database files are created with the postmap(1) or postalias(1)
+command. The database name as used in "lmdb:table" is the database
+file name without the ".lmdb" suffix. This database type has
+unexpected limitations and is therefore not part of the stable
+Postfix release.
+
 <dt> <b>ldap</b> (read-only) </dt>
 
 <dd> Perform lookups using the LDAP protocol. Configuration details
diff --git a/postfix/proto/INSTALL.html b/postfix/proto/INSTALL.html
index 6e26141a0..a4bb6ac46 100644
--- a/postfix/proto/INSTALL.html
+++ b/postfix/proto/INSTALL.html
@@ -229,21 +229,25 @@ $ make
 
 <p> and so on. In some cases, optimization is turned off automatically. </p>
 
-<h3>4.3 - Building with optional extensions</h3>
+<h3>4.3 - Building with optional features</h3>
 
 By default, Postfix builds as a mail system with relatively few
 bells and whistles. Support for third-party databases etc.
-must be configured when Postfix is compiled.  The following documents describe how to build Postfix with support for extensions:
+must be configured when Postfix is compiled.  The following documents
+describe how to build Postfix with support for optional features:
 
 <blockquote>
 <table border="1">
 
-<tr> <th>Postfix extension </th> <th>Document </th> <th>Availability</th>
+<tr> <th>Optional feature </th> <th>Document </th> <th>Availability</th>
 </tr>
 
 <tr> <td> Berkeley DB database</td> <td>DB_README</td> <td> Postfix
 1.0 </td> </tr>
 
+<tr> <td> LMDB database</td> <td>LMDB_README</td> <td> Postfix
+2.11 </td> </tr>
+
 <tr> <td> LDAP database</td> <td>LDAP_README</td> <td> Postfix
 1.0 </td> </tr>
 
diff --git a/postfix/proto/LMDB_README.html b/postfix/proto/LMDB_README.html
new file mode 100644
index 000000000..2f7b4248f
--- /dev/null
+++ b/postfix/proto/LMDB_README.html
@@ -0,0 +1,190 @@
+<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN"
+        "http://www.w3.org/TR/html4/loose.dtd">
+
+<html>
+
+<head>
+
+<title>Postfix OpenLDAP LMDB Howto</title>
+
+<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
+
+</head>
+
+<body>
+
+<h1><img src="postfix-logo.jpg" width="203" height="98" ALT="">Postfix OpenLDAP LMDB Howto</h1>
+
+<hr>
+
+<h2>Introduction</h2>
+
+<p> Postfix uses databases of various kinds to store and look up
+information. Postfix databases are specified as "type:name".
+OpenLDAP LMDB implements the Postfix database type "lmdb".
+The name of a Postfix OpenLDAP LMDB database is the name
+of the database file without the ".lmdb" suffix. OpenLDAP LMDB databases
+are maintained with the postmap(1) command.  </p>
+
+<p> This document describes: </p>
+
+<ol>
+
+<li> <p> How to build Postfix <a href="#with_lmdb">with OpenLDAP
+LMDB support</a>. </p>
+
+<li> <p> How to <a href="#configure">configure</a> LMDB settings. </p>
+
+<li> <p> Missing <a href="#pthread">pthread</a> library trouble. </p>
+
+</ol>
+
+<blockquote> <p> Caution: the current Postfix LMDB client has <a
+href="#limitations">unexpected limitations</a>. For this reason,
+LMDB support is not part of the stable Postfix release. </p>
+</blockquote>
+
+<h2><a name="with_lmdb">Building Postfix with OpenLDAP LMDB support</a></h2>
+
+<p> Postfix normally does not enable OpenLDAP LMDB support.
+To build Postfix after you installed OpenLDAP LMDB from
+source code, use something like: </p>
+
+<blockquote>
+<pre>
+% make makefiles CCARGS="-DHAS_LMDB -I/usr/local/include" \
+    AUXLIBS="-L/usr/local/lib -llmdb"
+% make
+</pre>
+</blockquote>
+
+<p> Solaris needs this: </p>
+
+<blockquote>
+<pre>
+% make makefiles CCARGS="-DHAS_LMDB -I/usr/local/include" \
+    AUXLIBS="-R/usr/local/lib -L/usr/local/lib -llmdb"
+% make
+</pre>
+</blockquote>
+
+<p> The exact pathnames depend on how OpenLDAP LMDB was installed. </p>
+
+<h2><a name="configure">Configure LMDB settings</a></h2>
+
+<p> Postfix provides a configuration parameter that controls how
+large an OpenLDAP LMDB database may grow. </p>
+
+<ul>
+
+<li> <p> lmdb_map_size (default: 10 MBytes per
+table).  This setting controls how large any OpenLDAP LMDB database
+may grow. It must be set large enough to accommodate the largest
+table that Postfix will use. </p>
+
+</ul>
+
+<h2><a name="pthread">Missing pthread library trouble</a></h2>
+
+<p> When building Postfix fails with: </p>
+
+<blockquote>
+<pre>
+undefined reference to `pthread_mutexattr_destroy'
+undefined reference to `pthread_mutexattr_init'
+undefined reference to `pthread_mutex_lock'
+</pre>
+</blockquote>
+
+<p> Add the "-lpthread" library to the "make makefiles" command. </p>
+
+<blockquote>
+<pre>
+% make makefiles .... AUXLIBS="... -lpthread"
+</pre>
+</blockquote>
+
+<p> Source code for OpenLDAP LMDB is available at
+http://www.openldap.org.
+More information is available at
+http://highlandsun.com/hyc/mdb/. </p>
+
+<h2><a name="limitations">Limitations of Postfix LMDB databases. </a> </h2>
+
+<ul>
+
+<li> <p> <strong>Unexpected postmap/postalias "database full" errors.
+</strong></p>
+
+<p> Even if the "postmap filename" command succeeds, the exact same
+command, with the exact same input data, may fail subsequently with
+an MDB_MAP_FULL error. The reason is that unlike other Postfix
+databases such as "hash" or "btree", </p>
+
+<ul>
+
+<li> <p> LMDB databases have a hard size limit (configured with the
+lmdb_map_size configuration parameter). </p>
+
+<li> <p> The Postfix LMDB database client does not implement the
+"truncate" operation.  Instead it saves all store requests to a
+transaction (which takes up space in addition to the existing data),
+and commits the transaction when the database is closed.  Only then
+can the space for old data be reused.  </p>
+
+</ul>
+
+<p> This postmap(1) or postalias(1) command failure does not affect
+Postfix availability, because the old data still exists in the
+database. </p>
+
+<p> To recover, increase the lmdb_map_size limit in main.cf, and
+retry the postmap(1) or postalias(1) command.  </p>
+
+<li> <p> <strong>Postfix daemon "database full" errors. </strong></p>
+
+<p> Unfortunately, "database full" problems will affect Postfix
+availability with daemon programs such as postscreen(8), tlsmgr(8)
+or verify(8). These daemon programs will continue to fail until
+someone increases the lmdb_map_size parameter value. Meanwhile,
+mail processing comes to a halt. </p>
+
+<li> <p> <strong>Non-obvious recovery from a corrupted database.
+</strong></p>
+
+<p> Unlike other Postfix databases such as "hash" or "btree", you
+can't rebuild a corrupted LMDB database simply by running postmap(1)
+or postalias(1), as those commands will crash, too. </p>
+
+<p> The reason for this limitation is that the Postfix LMDB database
+client does not implement the database "truncate" operation.  Instead
+it tries to save all store requests to a transaction for later
+processing.  That is obviously not possible with a corrupted database
+file. </p>
+
+<p> To recover, you must first delete the ".lmdb" file by hand, and
+only then you can retry the postmap(1) or postalias(1) command.
+</p>
+
+<li> <p> <strong>Incompatibility with tlsmgr(8). </strong></p>
+
+<p> The Postfix LMDB database client breaks tlsmgr(8) TLS session
+cache management. Specifically, it breaks how tlsmgr(8) clears its
+TLS session cache databases upon start-up, it breaks how tlsmgr(8)
+looks up new TLS session cache entries, and it breaks how tlsmgr(8)
+automatically recovers from a corrupted database file.  <p>
+
+<p> The reason for these limitations is that the Postfix LMDB
+database client does not implement the database "truncate" operation.
+Instead it saves all store requests to a transaction which it commits
+only when the database is closed. Therefore, tlsmgr(8) will never
+find any entries that it stores after opening its TLS session cache
+databases. And when the database becomes corrupted, tlsmgr(8) will
+keep crashing until someone removes the file ".lmdb" file by hand.
+</p>
+
+</ul>
+
+</body>
+
+</html>
diff --git a/postfix/proto/Makefile.in b/postfix/proto/Makefile.in
index d71454fc0..e9a69cd15 100644
--- a/postfix/proto/Makefile.in
+++ b/postfix/proto/Makefile.in
@@ -23,6 +23,7 @@ HTML	= ../html/ADDRESS_CLASS_README.html \
 	../html/LDAP_README.html \
 	../html/LINUX_README.html \
 	../html/LOCAL_RECIPIENT_README.html ../html/MAILDROP_README.html \
+	../html/LMDB_README.html \
 	../html/MEMCACHE_README.html \
 	../html/MILTER_README.html \
 	../html/MULTI_INSTANCE_README.html \
@@ -64,6 +65,7 @@ README	= ../README_FILES/ADDRESS_CLASS_README \
 	../README_FILES/LDAP_README \
 	../README_FILES/LINUX_README \
 	../README_FILES/LOCAL_RECIPIENT_README ../README_FILES/MAILDROP_README \
+	../README_FILES/LMDB_README \
 	../README_FILES/MEMCACHE_README \
 	../README_FILES/MILTER_README \
 	../README_FILES/MULTI_INSTANCE_README \
@@ -201,6 +203,9 @@ clobber:
 ../html/MAILDROP_README.html: MAILDROP_README.html
 	$(POSTLINK) $? >$@
 
+../html/LMDB_README.html: LMDB_README.html
+	$(POSTLINK) $? >$@
+
 ../html/MEMCACHE_README.html: MEMCACHE_README.html
 	$(POSTLINK) $? >$@
 
@@ -360,6 +365,9 @@ clobber:
 ../README_FILES/MAILDROP_README: MAILDROP_README.html
 	$(HT2READ) $? >$@
 
+../README_FILES/LMDB_README: LMDB_README.html
+	$(HT2READ) $? >$@
+
 ../README_FILES/MEMCACHE_README: MEMCACHE_README.html
 	$(HT2READ) $? >$@
 
diff --git a/postfix/proto/postconf.proto b/postfix/proto/postconf.proto
index 18d27d10f..8ca20beed 100644
--- a/postfix/proto/postconf.proto
+++ b/postfix/proto/postconf.proto
@@ -2831,6 +2831,17 @@ The default time unit is d (days).
 Specify 0 when mail delivery should be tried only once.
 </p>
 
+%PARAM lmdb_map_size 10485760
+
+<p>
+The per-table size limit for programs that create OpenLDAP LMDB
+tables.  Specify a byte count.
+</p>
+
+<p>
+This feature is available in Postfix 2.11 and later.
+</p>
+
 %PARAM message_size_limit 10240000
 
 <p>
diff --git a/postfix/src/global/Makefile.in b/postfix/src/global/Makefile.in
index 664d7726f..1b0e570fc 100644
--- a/postfix/src/global/Makefile.in
+++ b/postfix/src/global/Makefile.in
@@ -16,7 +16,7 @@ SRCS	= abounce.c anvil_clnt.c been_here.c bounce.c bounce_log.c \
 	mail_params.c mail_pathname.c mail_queue.c mail_run.c \
 	mail_scan_dir.c mail_stream.c mail_task.c mail_trigger.c maps.c \
 	mark_corrupt.c match_parent_style.c mbox_conf.c mbox_open.c \
-	mime_state.c mkmap_cdb.c mkmap_db.c mkmap_dbm.c mkmap_open.c \
+	mime_state.c mkmap_cdb.c mkmap_db.c mkmap_dbm.c mkmap_lmdb.c mkmap_open.c \
 	mkmap_sdbm.c msg_stats_print.c msg_stats_scan.c mynetworks.c \
 	mypwd.c namadr_list.c off_cvt.c opened.c own_inet_addr.c \
 	pipe_command.c post_mail.c quote_821_local.c quote_822_local.c \
@@ -50,7 +50,7 @@ OBJS	= abounce.o anvil_clnt.o been_here.o bounce.o bounce_log.o \
 	mail_params.o mail_pathname.o mail_queue.o mail_run.o \
 	mail_scan_dir.o mail_stream.o mail_task.o mail_trigger.o maps.o \
 	mark_corrupt.o match_parent_style.o mbox_conf.o mbox_open.o \
-	mime_state.o mkmap_cdb.o mkmap_db.o mkmap_dbm.o mkmap_open.o \
+	mime_state.o mkmap_cdb.o mkmap_db.o mkmap_dbm.o mkmap_lmdb.o mkmap_open.o \
 	mkmap_sdbm.o msg_stats_print.o msg_stats_scan.o mynetworks.o \
 	mypwd.o namadr_list.o off_cvt.o opened.o own_inet_addr.o \
 	pipe_command.o post_mail.o quote_821_local.o quote_822_local.o \
@@ -740,6 +740,7 @@ data_redirect.o: ../../include/dict.h
 data_redirect.o: ../../include/dict_cdb.h
 data_redirect.o: ../../include/dict_db.h
 data_redirect.o: ../../include/dict_dbm.h
+data_redirect.o: ../../include/dict_lmdb.h
 data_redirect.o: ../../include/msg.h
 data_redirect.o: ../../include/myflock.h
 data_redirect.o: ../../include/name_code.h
@@ -1434,6 +1435,7 @@ mail_params.o: ../../include/argv.h
 mail_params.o: ../../include/attr.h
 mail_params.o: ../../include/dict.h
 mail_params.o: ../../include/dict_db.h
+mail_params.o: ../../include/dict_lmdb.h
 mail_params.o: ../../include/get_hostname.h
 mail_params.o: ../../include/inet_addr_list.h
 mail_params.o: ../../include/inet_proto.h
@@ -1690,12 +1692,29 @@ mkmap_fail.o: ../../include/vstream.h
 mkmap_fail.o: ../../include/vstring.h
 mkmap_fail.o: mkmap.h
 mkmap_fail.o: mkmap_fail.c
+mkmap_lmdb.o: ../../include/argv.h
+mkmap_lmdb.o: ../../include/dict.h
+mkmap_lmdb.o: ../../include/dict_lmdb.h
+mkmap_lmdb.o: ../../include/msg.h
+mkmap_lmdb.o: ../../include/myflock.h
+mkmap_lmdb.o: ../../include/mymalloc.h
+mkmap_lmdb.o: ../../include/stringops.h
+mkmap_lmdb.o: ../../include/sys_defs.h
+mkmap_lmdb.o: ../../include/vbuf.h
+mkmap_lmdb.o: ../../include/vstream.h
+mkmap_lmdb.o: ../../include/vstring.h
+mkmap_lmdb.o: ../../include/warn_stat.h
+mkmap_lmdb.o: mail_conf.h
+mkmap_lmdb.o: mail_params.h
+mkmap_lmdb.o: mkmap.h
+mkmap_lmdb.o: mkmap_lmdb.c
 mkmap_open.o: ../../include/argv.h
 mkmap_open.o: ../../include/dict.h
 mkmap_open.o: ../../include/dict_cdb.h
 mkmap_open.o: ../../include/dict_db.h
 mkmap_open.o: ../../include/dict_dbm.h
 mkmap_open.o: ../../include/dict_fail.h
+mkmap_open.o: ../../include/dict_lmdb.h
 mkmap_open.o: ../../include/dict_sdbm.h
 mkmap_open.o: ../../include/msg.h
 mkmap_open.o: ../../include/myflock.h
diff --git a/postfix/src/global/data_redirect.c b/postfix/src/global/data_redirect.c
index 096e58c14..7f497ca49 100644
--- a/postfix/src/global/data_redirect.c
+++ b/postfix/src/global/data_redirect.c
@@ -72,6 +72,7 @@
 #include <dict_db.h>
 #include <dict_dbm.h>
 #include <dict_cdb.h>
+#include <dict_lmdb.h>
 #include <warn_stat.h>
 
 /* Global directory. */
@@ -99,6 +100,7 @@ static const NAME_CODE data_redirect_map_types[] = {
     DICT_TYPE_HASH, 1,
     DICT_TYPE_BTREE, 1,
     DICT_TYPE_DBM, 1,
+    DICT_TYPE_LMDB, 1,
     DICT_TYPE_CDB, 1,			/* not a read-write map type */
     "sdbm", 1,				/* legacy 3rd-party TLS */
     "dbz", 1,				/* just in case */
diff --git a/postfix/src/global/mail_params.c b/postfix/src/global/mail_params.c
index 0e098b3db..94ea155d7 100644
--- a/postfix/src/global/mail_params.c
+++ b/postfix/src/global/mail_params.c
@@ -96,6 +96,7 @@
 /*	char   *var_proxywrite_service;
 /*	int	var_db_create_buf;
 /*	int	var_db_read_buf;
+/*	int	var_lmdb_map_size;
 /*	int	var_mime_maxdepth;
 /*	int	var_mime_bound_len;
 /*	int	var_header_limit;
@@ -177,6 +178,9 @@
 #ifdef HAS_DB
 #include <dict_db.h>
 #endif
+#ifdef HAS_LMDB
+#include <dict_lmdb.h>
+#endif
 #include <inet_proto.h>
 #include <vstring_vstream.h>
 #include <iostuff.h>
@@ -284,6 +288,7 @@ char   *var_proxymap_service;
 char   *var_proxywrite_service;
 int     var_db_create_buf;
 int     var_db_read_buf;
+int     var_lmdb_map_size;
 int     var_mime_maxdepth;
 int     var_mime_bound_len;
 int     var_header_limit;
@@ -596,6 +601,7 @@ void    mail_params_init()
 	VAR_FAULT_INJ_CODE, DEF_FAULT_INJ_CODE, &var_fault_inj_code, 0, 0,
 	VAR_DB_CREATE_BUF, DEF_DB_CREATE_BUF, &var_db_create_buf, 1, 0,
 	VAR_DB_READ_BUF, DEF_DB_READ_BUF, &var_db_read_buf, 1, 0,
+	VAR_LMDB_MAP_SIZE, DEF_LMDB_MAP_SIZE, &var_lmdb_map_size, 1, 0,
 	VAR_HEADER_LIMIT, DEF_HEADER_LIMIT, &var_header_limit, 1, 0,
 	VAR_TOKEN_LIMIT, DEF_TOKEN_LIMIT, &var_token_limit, 1, 0,
 	VAR_MIME_MAXDEPTH, DEF_MIME_MAXDEPTH, &var_mime_maxdepth, 1, 0,
@@ -712,6 +718,9 @@ void    mail_params_init()
     check_overlap();
 #ifdef HAS_DB
     dict_db_cache_size = var_db_read_buf;
+#endif
+#ifdef HAS_LMDB
+    dict_lmdb_map_size = var_lmdb_map_size;
 #endif
     inet_windowsize = var_inet_windowsize;
 
diff --git a/postfix/src/global/mail_params.h b/postfix/src/global/mail_params.h
index 9c5fde004..53aa582cb 100644
--- a/postfix/src/global/mail_params.h
+++ b/postfix/src/global/mail_params.h
@@ -2727,6 +2727,13 @@ extern int var_db_create_buf;
 #define DEF_DB_READ_BUF			(128 *1024)
 extern int var_db_read_buf;
 
+ /*
+  * OpenLDAP LMDB memory map size.
+  */
+#define VAR_LMDB_MAP_SIZE		"lmdb_map_size"
+#define DEF_LMDB_MAP_SIZE		(16 * 1024 *1024)
+extern int var_lmdb_map_size;
+
  /*
   * Named queue file attributes.
   */
diff --git a/postfix/src/global/mail_version.h b/postfix/src/global/mail_version.h
index 27b088b89..702a68240 100644
--- a/postfix/src/global/mail_version.h
+++ b/postfix/src/global/mail_version.h
@@ -20,7 +20,7 @@
   * Patches change both the patchlevel and the release date. Snapshots have no
   * patchlevel; they change the release date only.
   */
-#define MAIL_RELEASE_DATE	"20130211"
+#define MAIL_RELEASE_DATE	"20130315"
 #define MAIL_VERSION_NUMBER	"2.11"
 
 #ifdef SNAPSHOT
diff --git a/postfix/src/global/mkmap.h b/postfix/src/global/mkmap.h
index d74a9125d..c131d4618 100644
--- a/postfix/src/global/mkmap.h
+++ b/postfix/src/global/mkmap.h
@@ -39,6 +39,7 @@ extern MKMAP *mkmap_dbm_open(const char *);
 extern MKMAP *mkmap_cdb_open(const char *);
 extern MKMAP *mkmap_hash_open(const char *);
 extern MKMAP *mkmap_btree_open(const char *);
+extern MKMAP *mkmap_lmdb_open(const char *);
 extern MKMAP *mkmap_sdbm_open(const char *);
 extern MKMAP *mkmap_proxy_open(const char *);
 extern MKMAP *mkmap_fail_open(const char *);
diff --git a/postfix/src/global/mkmap_lmdb.c b/postfix/src/global/mkmap_lmdb.c
new file mode 100644
index 000000000..7ab120954
--- /dev/null
+++ b/postfix/src/global/mkmap_lmdb.c
@@ -0,0 +1,126 @@
+/*++
+/* NAME
+/*	mkmap_lmdb 3
+/* SUMMARY
+/*	create or open database, LMDB style
+/* SYNOPSIS
+/*	#include <mkmap.h>
+/*
+/*	MKMAP	*mkmap_lmdb_open(path)
+/*	const char *path;
+/*
+/* DESCRIPTION
+/*	This module implements support for creating LMDB databases.
+/*
+/*	mkmap_lmdb_open() takes a file name, appends the ".lmdb"
+/*	suffix, and does whatever initialization is required
+/*	before the OpenLDAP LMDB open routine is called.
+/*
+/*	All errors are fatal.
+/* SEE ALSO
+/*	dict_lmdb(3), LMDB dictionary interface.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Howard Chu
+/*	Symas Corporation
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <stringops.h>
+#include <dict.h>
+#include <dict_lmdb.h>
+#include <myflock.h>
+#include <warn_stat.h>
+
+#if defined(HAS_LMDB) && defined(SNAPSHOT)
+#ifdef PATH_LMDB_H
+#include PATH_LMDB_H
+#else
+#include <lmdb.h>
+#endif
+
+/* Global library. */
+
+#include <mail_conf.h>
+#include <mail_params.h>
+
+/* Application-specific. */
+
+#include "mkmap.h"
+
+int     var_proc_limit;
+
+/* mkmap_lmdb_open */
+
+MKMAP  *mkmap_lmdb_open(const char *path)
+{
+    MKMAP  *mkmap = (MKMAP *) mymalloc(sizeof(*mkmap));
+    static const CONFIG_INT_TABLE int_table[] = {
+	VAR_PROC_LIMIT, DEF_PROC_LIMIT, &var_proc_limit, 1, 0,
+	0,
+    };
+
+    get_mail_conf_int_table(int_table);
+
+    /*
+     * XXX Why is this not set in mail_params.c (with proper #ifdefs)?
+     * 
+     * Override the default per-table map size for map (re)builds.
+     * 
+     * lmdb_map_size is defined in util/dict_lmdb.c and defaults to 10MB. It
+     * needs to be large enough to contain the largest tables in use.
+     * 
+     * XXX This should be specified via the DICT interface so that the buffer
+     * size becomes an object property, instead of being specified by poking
+     * a global variable so that it becomes a class property.
+     * 
+     * XXX Wietse disagrees: storage infrastructure that requires up-front
+     * max-size information is evil. This unlike Postfix (e.g. line length or
+     * process count) limits which are a defense against out-of-control or
+     * malicious external actors.
+     * 
+     * XXX Need to check that an existing table can be rebuilt with a larger
+     * size limit than was used for the initial build.
+     */
+    dict_lmdb_map_size = var_lmdb_map_size;
+
+    /*
+     * XXX Why is this not set in mail_params.c (with proper #ifdefs)?
+     * 
+     * Set the max number of concurrent readers per table. This is the
+     * maximum number of postfix processes, plus some extra for CLI users.
+     * 
+     * XXX Postfix uses asynchronous or blocking I/O with single-threaded
+     * processes so this limit will never be reached, assuming that the limit
+     * is a per-client property, not a shared database property.
+     */
+    dict_lmdb_max_readers = var_proc_limit * 2 + 16;
+
+    /*
+     * Fill in the generic members.
+     */
+    mkmap->open = dict_lmdb_open;
+    mkmap->after_open = 0;
+    mkmap->after_close = 0;
+
+    /*
+     * LMDB uses MVCC so it needs no special lock management here.
+     */
+
+    return (mkmap);
+}
+
+#endif
diff --git a/postfix/src/global/mkmap_open.c b/postfix/src/global/mkmap_open.c
index d939d443d..e3e2d9595 100644
--- a/postfix/src/global/mkmap_open.c
+++ b/postfix/src/global/mkmap_open.c
@@ -65,6 +65,7 @@
 #include <dict_db.h>
 #include <dict_cdb.h>
 #include <dict_dbm.h>
+#include <dict_lmdb.h>
 #include <dict_sdbm.h>
 #include <dict_proxy.h>
 #include <dict_fail.h>
@@ -100,6 +101,9 @@ static const MKMAP_OPEN_INFO mkmap_types[] = {
 #ifdef HAS_DB
     DICT_TYPE_HASH, mkmap_hash_open,
     DICT_TYPE_BTREE, mkmap_btree_open,
+#endif
+#if defined(HAS_LMDB) && defined(SNAPSHOT)
+    DICT_TYPE_LMDB, mkmap_lmdb_open,
 #endif
     DICT_TYPE_FAIL, mkmap_fail_open,
     0,
diff --git a/postfix/src/util/Makefile.in b/postfix/src/util/Makefile.in
index ea44c4ae5..14216c62b 100644
--- a/postfix/src/util/Makefile.in
+++ b/postfix/src/util/Makefile.in
@@ -4,7 +4,7 @@ SRCS	= alldig.c allprint.c argv.c argv_split.c attr_clnt.c attr_print0.c \
 	attr_scan_plain.c auto_clnt.c base64_code.c basename.c binhash.c \
 	chroot_uid.c cidr_match.c clean_env.c close_on_exec.c concatenate.c \
 	ctable.c dict.c dict_alloc.c dict_cdb.c dict_cidr.c dict_db.c \
-	dict_dbm.c dict_debug.c dict_env.c dict_ht.c dict_ni.c dict_nis.c \
+	dict_dbm.c dict_debug.c dict_env.c dict_ht.c dict_lmdb.c dict_ni.c dict_nis.c \
 	dict_nisplus.c dict_open.c dict_pcre.c dict_regexp.c dict_sdbm.c \
 	dict_static.c dict_tcp.c dict_unix.c dir_forest.c doze.c dummy_read.c \
 	dummy_write.c duplex_pipe.c environ.c events.c exec_command.c \
@@ -41,7 +41,7 @@ OBJS	= alldig.o allprint.o argv.o argv_split.o attr_clnt.o attr_print0.o \
 	attr_scan_plain.o auto_clnt.o base64_code.o basename.o binhash.o \
 	chroot_uid.o cidr_match.o clean_env.o close_on_exec.o concatenate.o \
 	ctable.o dict.o dict_alloc.o dict_cdb.o dict_cidr.o dict_db.o \
-	dict_dbm.o dict_debug.o dict_env.o dict_ht.o dict_ni.o dict_nis.o \
+	dict_dbm.o dict_debug.o dict_env.o dict_ht.o dict_lmdb.o dict_ni.o dict_nis.o \
 	dict_nisplus.o dict_open.o dict_pcre.o dict_regexp.o dict_sdbm.o \
 	dict_static.o dict_tcp.o dict_unix.o dir_forest.o doze.o dummy_read.o \
 	dummy_write.o duplex_pipe.o environ.o events.o exec_command.o \
@@ -76,7 +76,7 @@ OBJS	= alldig.o allprint.o argv.o argv_split.o attr_clnt.o attr_print0.o \
 HDRS	= argv.h attr.h attr_clnt.h auto_clnt.h base64_code.h binhash.h \
 	chroot_uid.h cidr_match.h clean_env.h connect.h ctable.h dict.h \
 	dict_cdb.h dict_cidr.h dict_db.h dict_dbm.h dict_env.h dict_ht.h \
-	dict_ni.h dict_nis.h dict_nisplus.h dict_pcre.h dict_regexp.h \
+	dict_lmdb.h dict_ni.h dict_nis.h dict_nisplus.h dict_pcre.h dict_regexp.h \
 	dict_sdbm.h dict_static.h dict_tcp.h dict_unix.h dir_forest.h \
 	events.h exec_command.h find_inet.h fsspace.h fullname.h \
 	get_domainname.h get_hostname.h hex_code.h hex_quote.h host_port.h \
@@ -983,6 +983,21 @@ dict_ht.o: sys_defs.h
 dict_ht.o: vbuf.h
 dict_ht.o: vstream.h
 dict_ht.o: vstring.h
+dict_lmdb.o: argv.h
+dict_lmdb.o: dict.h
+dict_lmdb.o: dict_lmdb.c
+dict_lmdb.o: dict_lmdb.h
+dict_lmdb.o: htable.h
+dict_lmdb.o: iostuff.h
+dict_lmdb.o: msg.h
+dict_lmdb.o: myflock.h
+dict_lmdb.o: mymalloc.h
+dict_lmdb.o: stringops.h
+dict_lmdb.o: sys_defs.h
+dict_lmdb.o: vbuf.h
+dict_lmdb.o: vstream.h
+dict_lmdb.o: vstring.h
+dict_lmdb.o: warn_stat.h
 dict_ni.o: dict_ni.c
 dict_ni.o: sys_defs.h
 dict_nis.o: argv.h
@@ -1018,6 +1033,7 @@ dict_open.o: dict_dbm.h
 dict_open.o: dict_env.h
 dict_open.o: dict_fail.h
 dict_open.o: dict_ht.h
+dict_open.o: dict_lmdb.h
 dict_open.o: dict_ni.h
 dict_open.o: dict_nis.h
 dict_open.o: dict_nisplus.h
diff --git a/postfix/src/util/dict_lmdb.c b/postfix/src/util/dict_lmdb.c
new file mode 100644
index 000000000..e60d44a79
--- /dev/null
+++ b/postfix/src/util/dict_lmdb.c
@@ -0,0 +1,541 @@
+/*++
+/* NAME
+/*	dict_lmdb 3
+/* SUMMARY
+/*	dictionary manager interface to OpenLDAP LMDB files
+/* SYNOPSIS
+/*	#include <dict_lmdb.h>
+/*
+/*	DICT	*dict_lmdb_open(path, open_flags, dict_flags)
+/*	const char *name;
+/*	const char *path;
+/*	int	open_flags;
+/*	int	dict_flags;
+/* DESCRIPTION
+/*	dict_lmdb_open() opens the named LMDB database and makes it available
+/*	via the generic interface described in dict_open(3).
+/*
+/*	The dict_lmdb_map_size variable specifies a non-default per-table
+/*	memory map size.  The map size is 10MB.  The map size is also the
+/*	maximum size the table can grow to, so it must be set large enough
+/*	to accomodate the largest tables in use.
+/* DIAGNOSTICS
+/*	Fatal errors: cannot open file, file write error, out of memory.
+/* SEE ALSO
+/*	dict(3) generic dictionary manager
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Howard Chu
+/*	Symas Corporation
+/*--*/
+
+#include "sys_defs.h"
+
+#if defined(HAS_LMDB) && defined(SNAPSHOT)
+
+/* System library. */
+
+#include <sys/stat.h>
+#include <string.h>
+#include <unistd.h>
+
+#ifdef PATH_LMDB_H
+#include PATH_LMDB_H
+#else
+#include <lmdb.h>
+#endif
+
+/* Utility library. */
+
+#include "msg.h"
+#include "mymalloc.h"
+#include "htable.h"
+#include "iostuff.h"
+#include "vstring.h"
+#include "myflock.h"
+#include "stringops.h"
+#include "dict.h"
+#include "dict_lmdb.h"
+#include "warn_stat.h"
+
+/* Application-specific. */
+
+typedef struct {
+    DICT    dict;			/* generic members */
+    MDB_env *env;			/* LMDB environment */
+    MDB_dbi dbi;			/* database handle */
+    MDB_txn *txn;			/* write transaction for O_TRUNC */
+    MDB_cursor *cursor;			/* for sequence ops */
+    VSTRING *key_buf;			/* key buffer */
+    VSTRING *val_buf;			/* result buffer */
+} DICT_LMDB;
+
+#define SCOPY(buf, data, size) \
+    vstring_str(vstring_strncpy(buf ? buf : (buf = vstring_alloc(10)), data, size))
+
+size_t  dict_lmdb_map_size = (10 * 1024 * 1024);	/* 10MB default mmap
+							 * size */
+unsigned int dict_lmdb_max_readers = 216;	/* 200 postfix processes,
+						 * plus some extra */
+
+/* dict_lmdb_lookup - find database entry */
+
+static const char *dict_lmdb_lookup(DICT *dict, const char *name)
+{
+    DICT_LMDB *dict_lmdb = (DICT_LMDB *) dict;
+    MDB_val mdb_key;
+    MDB_val mdb_value;
+    MDB_txn *txn;
+    const char *result = 0;
+    int     status, klen;
+
+    dict->error = 0;
+    klen = strlen(name);
+
+    /*
+     * Sanity check.
+     */
+    if ((dict->flags & (DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL)) == 0)
+	msg_panic("dict_lmdb_lookup: no DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL flag");
+
+    /*
+     * Optionally fold the key.
+     */
+    if (dict->flags & DICT_FLAG_FOLD_FIX) {
+	if (dict->fold_buf == 0)
+	    dict->fold_buf = vstring_alloc(10);
+	vstring_strcpy(dict->fold_buf, name);
+	name = lowercase(vstring_str(dict->fold_buf));
+    }
+
+    /*
+     * Start a read transaction if there's no global txn.
+     */
+    if (dict_lmdb->txn)
+	txn = dict_lmdb->txn;
+    else if ((status = mdb_txn_begin(dict_lmdb->env, NULL, MDB_RDONLY, &txn)))
+	msg_fatal("%s: txn_begin(read) dictionary: %s", dict_lmdb->dict.name, mdb_strerror(status));
+
+    /*
+     * See if this LMDB file was written with one null byte appended to key
+     * and value.
+     */
+    if (dict->flags & DICT_FLAG_TRY1NULL) {
+	mdb_key.mv_data = (void *) name;
+	mdb_key.mv_size = klen + 1;
+	status = mdb_get(txn, dict_lmdb->dbi, &mdb_key, &mdb_value);
+	if (!status) {
+	    dict->flags &= ~DICT_FLAG_TRY0NULL;
+	    result = SCOPY(dict_lmdb->val_buf, mdb_value.mv_data, mdb_value.mv_size);
+	}
+    }
+
+    /*
+     * See if this LMDB file was written with no null byte appended to key
+     * and value.
+     */
+    if (result == 0 && (dict->flags & DICT_FLAG_TRY0NULL)) {
+	mdb_key.mv_data = (void *) name;
+	mdb_key.mv_size = klen;
+	status = mdb_get(txn, dict_lmdb->dbi, &mdb_key, &mdb_value);
+	if (!status) {
+	    dict->flags &= ~DICT_FLAG_TRY1NULL;
+	    result = SCOPY(dict_lmdb->val_buf, mdb_value.mv_data, mdb_value.mv_size);
+	}
+    }
+
+    /*
+     * Close the read txn if it's not the global txn.
+     */
+    if (!dict_lmdb->txn)
+	mdb_txn_abort(txn);
+
+    return (result);
+}
+
+/* dict_lmdb_update - add or update database entry */
+
+static int dict_lmdb_update(DICT *dict, const char *name, const char *value)
+{
+    DICT_LMDB *dict_lmdb = (DICT_LMDB *) dict;
+    MDB_val mdb_key;
+    MDB_val mdb_value;
+    MDB_txn *txn;
+    int     status;
+
+    dict->error = 0;
+
+    /*
+     * Sanity check.
+     */
+    if ((dict->flags & (DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL)) == 0)
+	msg_panic("dict_lmdb_update: no DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL flag");
+
+    /*
+     * Optionally fold the key.
+     */
+    if (dict->flags & DICT_FLAG_FOLD_FIX) {
+	if (dict->fold_buf == 0)
+	    dict->fold_buf = vstring_alloc(10);
+	vstring_strcpy(dict->fold_buf, name);
+	name = lowercase(vstring_str(dict->fold_buf));
+    }
+    mdb_key.mv_data = (void *) name;
+    mdb_value.mv_data = (void *) value;
+    mdb_key.mv_size = strlen(name);
+    mdb_value.mv_size = strlen(value);
+
+    /*
+     * If undecided about appending a null byte to key and value, choose a
+     * default depending on the platform.
+     */
+    if ((dict->flags & DICT_FLAG_TRY1NULL)
+	&& (dict->flags & DICT_FLAG_TRY0NULL)) {
+#ifdef LMDB_NO_TRAILING_NULL
+	dict->flags &= ~DICT_FLAG_TRY1NULL;
+#else
+	dict->flags &= ~DICT_FLAG_TRY0NULL;
+#endif
+    }
+
+    /*
+     * Optionally append a null byte to key and value.
+     */
+    if (dict->flags & DICT_FLAG_TRY1NULL) {
+	mdb_key.mv_size++;
+	mdb_value.mv_size++;
+    }
+
+    /*
+     * Start a write transaction if there's no global txn.
+     */
+    if (dict_lmdb->txn)
+	txn = dict_lmdb->txn;
+    else if ((status = mdb_txn_begin(dict_lmdb->env, NULL, 0, &txn)))
+	msg_fatal("%s: txn_begin(write) dictionary: %s", dict_lmdb->dict.name, mdb_strerror(status));
+
+    /*
+     * Do the update.
+     */
+    status = mdb_put(txn, dict_lmdb->dbi, &mdb_key, &mdb_value,
+	       (dict->flags & DICT_FLAG_DUP_REPLACE) ? 0 : MDB_NOOVERWRITE);
+    if (status) {
+	if (status == MDB_KEYEXIST) {
+	    if (dict->flags & DICT_FLAG_DUP_IGNORE)
+		 /* void */ ;
+	    else if (dict->flags & DICT_FLAG_DUP_WARN)
+		msg_warn("%s: duplicate entry: \"%s\"", dict_lmdb->dict.name, name);
+	    else
+		msg_fatal("%s: duplicate entry: \"%s\"", dict_lmdb->dict.name, name);
+	} else {
+	    msg_fatal("error writing LMDB database %s: %s", dict_lmdb->dict.name, mdb_strerror(status));
+	}
+    }
+
+    /*
+     * Commit the transaction if it's not the global txn.
+     */
+    if (!dict_lmdb->txn && ((status = mdb_txn_commit(txn))))
+	msg_fatal("error committing LMDB database %s: %s", dict_lmdb->dict.name, mdb_strerror(status));
+
+    return (status);
+}
+
+/* dict_lmdb_delete - delete one entry from the dictionary */
+
+static int dict_lmdb_delete(DICT *dict, const char *name)
+{
+    DICT_LMDB *dict_lmdb = (DICT_LMDB *) dict;
+    MDB_val mdb_key;
+    MDB_txn *txn;
+    int     status = 1, klen, rc;
+
+    dict->error = 0;
+    klen = strlen(name);
+
+    /*
+     * Sanity check.
+     */
+    if ((dict->flags & (DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL)) == 0)
+	msg_panic("dict_lmdb_delete: no DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL flag");
+
+    /*
+     * Optionally fold the key.
+     */
+    if (dict->flags & DICT_FLAG_FOLD_FIX) {
+	if (dict->fold_buf == 0)
+	    dict->fold_buf = vstring_alloc(10);
+	vstring_strcpy(dict->fold_buf, name);
+	name = lowercase(vstring_str(dict->fold_buf));
+    }
+
+    /*
+     * Start a write transaction if there's no global txn.
+     */
+    if (dict_lmdb->txn)
+	txn = dict_lmdb->txn;
+    else if ((status = mdb_txn_begin(dict_lmdb->env, NULL, 0, &txn)))
+	msg_fatal("%s: txn_begin(write) dictionary: %s", dict_lmdb->dict.name, mdb_strerror(status));
+
+    /*
+     * See if this LMDB file was written with one null byte appended to key
+     * and value.
+     */
+    if (dict->flags & DICT_FLAG_TRY1NULL) {
+	mdb_key.mv_data = (void *) name;
+	mdb_key.mv_size = klen + 1;
+	status = mdb_del(txn, dict_lmdb->dbi, &mdb_key, NULL);
+	if (status) {
+	    if (status == MDB_NOTFOUND)
+		status = 1;
+	    else
+		msg_fatal("error deleting from %s: %s", dict_lmdb->dict.name, mdb_strerror(status));
+	} else {
+	    dict->flags &= ~DICT_FLAG_TRY0NULL;	/* found */
+	}
+    }
+
+    /*
+     * See if this LMDB file was written with no null byte appended to key
+     * and value.
+     */
+    if (status > 0 && (dict->flags & DICT_FLAG_TRY0NULL)) {
+	mdb_key.mv_data = (void *) name;
+	mdb_key.mv_size = klen;
+	status = mdb_del(txn, dict_lmdb->dbi, &mdb_key, NULL);
+	if (status) {
+	    if (status == MDB_NOTFOUND)
+		status = 1;
+	    else
+		msg_fatal("error deleting from %s: %s", dict_lmdb->dict.name, mdb_strerror(status));
+	} else {
+	    dict->flags &= ~DICT_FLAG_TRY1NULL;	/* found */
+	}
+    }
+
+    /*
+     * Commit the transaction if it's not the global txn.
+     */
+    if (!dict_lmdb->txn && ((rc = mdb_txn_commit(txn))))
+	msg_fatal("error committing LMDB database %s: %s", dict_lmdb->dict.name, mdb_strerror(rc));
+
+    return (status);
+}
+
+/* traverse the dictionary */
+
+static int dict_lmdb_sequence(DICT *dict, int function,
+			              const char **key, const char **value)
+{
+    const char *myname = "dict_lmdb_sequence";
+    DICT_LMDB *dict_lmdb = (DICT_LMDB *) dict;
+    MDB_val mdb_key;
+    MDB_val mdb_value;
+    MDB_txn *txn;
+    MDB_cursor_op op;
+    int     status;
+
+    dict->error = 0;
+
+    /*
+     * Determine the seek function.
+     */
+    switch (function) {
+    case DICT_SEQ_FUN_FIRST:
+	op = MDB_FIRST;
+	break;
+    case DICT_SEQ_FUN_NEXT:
+	op = MDB_NEXT;
+	break;
+    default:
+	msg_panic("%s: invalid function: %d", myname, function);
+    }
+
+    /*
+     * Open a read transaction and cursor if needed.
+     */
+    if (dict_lmdb->cursor == 0) {
+	if ((status = mdb_txn_begin(dict_lmdb->env, NULL, MDB_RDONLY, &txn)))
+	    msg_fatal("%s: txn_begin(read) dictionary: %s", dict_lmdb->dict.name, mdb_strerror(status));
+	if ((status = mdb_cursor_open(txn, dict_lmdb->dbi, &dict_lmdb->cursor)))
+	    msg_fatal("%s: cursor_open dictionary: %s", dict_lmdb->dict.name, mdb_strerror(status));
+    }
+
+    /*
+     * Database lookup.
+     */
+    status = mdb_cursor_get(dict_lmdb->cursor, &mdb_key, &mdb_value, op);
+    if (status && status != MDB_NOTFOUND)
+	msg_fatal("%s: seeking dictionary: %s", dict_lmdb->dict.name, mdb_strerror(status));
+
+    if (status == MDB_NOTFOUND) {
+
+	/*
+	 * Caller must read to end, to ensure cursor gets closed.
+	 */
+	status = 1;
+	txn = mdb_cursor_txn(dict_lmdb->cursor);
+	mdb_cursor_close(dict_lmdb->cursor);
+	mdb_txn_abort(txn);
+	dict_lmdb->cursor = 0;
+    } else {
+
+	/*
+	 * Copy the key so that it is guaranteed null terminated.
+	 */
+	*key = SCOPY(dict_lmdb->key_buf, mdb_key.mv_data, mdb_key.mv_size);
+
+	if (mdb_value.mv_data != 0 && mdb_value.mv_size > 0) {
+
+	    /*
+	     * Copy the value so that it is guaranteed null terminated.
+	     */
+	    *value = SCOPY(dict_lmdb->val_buf, mdb_value.mv_data, mdb_value.mv_size);
+	    status = 0;
+	}
+    }
+
+    return (status);
+}
+
+/* dict_lmdb_lock - noop lock handler */
+
+static int dict_lmdb_lock(DICT *dict, int unused_op)
+{
+    /* LMDB does its own concurrency control */
+    return 0;
+}
+
+/* dict_lmdb_close - disassociate from data base */
+
+static void dict_lmdb_close(DICT *dict)
+{
+    DICT_LMDB *dict_lmdb = (DICT_LMDB *) dict;
+
+    if (dict_lmdb->txn) {
+	int     status = mdb_txn_commit(dict_lmdb->txn);
+
+	if (status)
+	    msg_fatal("%s: closing dictionary: %s", dict_lmdb->dict.name, mdb_strerror(status));
+	dict_lmdb->cursor = NULL;
+    }
+    if (dict_lmdb->cursor) {
+	MDB_txn *txn = mdb_cursor_txn(dict_lmdb->cursor);
+
+	mdb_cursor_close(dict_lmdb->cursor);
+	mdb_txn_abort(txn);
+    }
+    if (dict_lmdb->dict.stat_fd >= 0)
+	close(dict_lmdb->dict.stat_fd);
+    mdb_env_close(dict_lmdb->env);
+    if (dict_lmdb->key_buf)
+	vstring_free(dict_lmdb->key_buf);
+    if (dict_lmdb->val_buf)
+	vstring_free(dict_lmdb->val_buf);
+    if (dict->fold_buf)
+	vstring_free(dict->fold_buf);
+    dict_free(dict);
+}
+
+/* dict_lmdb_open - open LMDB data base */
+
+DICT   *dict_lmdb_open(const char *path, int open_flags, int dict_flags)
+{
+    DICT_LMDB *dict_lmdb;
+    struct stat st;
+    MDB_env *env;
+    MDB_txn *txn;
+    MDB_dbi dbi;
+    char   *mdb_path;
+    int     env_flags, status;
+
+    mdb_path = concatenate(path, ".lmdb", (char *) 0);
+
+    env_flags = MDB_NOSUBDIR;
+    if (open_flags == O_RDONLY)
+	env_flags |= MDB_RDONLY;
+
+    if ((status = mdb_env_create(&env)))
+	msg_fatal("env_create %s: %s", mdb_path, mdb_strerror(status));
+
+    if ((status = mdb_env_set_mapsize(env, dict_lmdb_map_size)))
+	msg_fatal("env_set_mapsize %s: %s", mdb_path, mdb_strerror(status));
+
+    if ((status = mdb_env_set_maxreaders(env, dict_lmdb_max_readers)))
+	msg_fatal("env_set_maxreaders %s: %s", mdb_path, mdb_strerror(status));
+
+    if ((status = mdb_env_open(env, mdb_path, env_flags, 0644)))
+	msg_fatal("env_open %s: %s", mdb_path, mdb_strerror(status));
+
+    if ((status = mdb_txn_begin(env, NULL, env_flags & MDB_RDONLY, &txn)))
+	msg_fatal("txn_begin %s: %s", mdb_path, mdb_strerror(status));
+
+    /*
+     * mdb_open requires a txn, but since the default DB always exists in an
+     * LMDB environment, we don't need to do anything else with the txn.
+     */
+    if ((status = mdb_open(txn, NULL, 0, &dbi)))
+	msg_fatal("mdb_open %s: %s", mdb_path, mdb_strerror(status));
+
+    /*
+     * However, if O_TRUNC was specified, we need to do it now. Also with
+     * O_TRUNC we keep this write txn for as long as the database is open,
+     * since we'll probably be doing a bulk import immediately after.
+     */
+    if (open_flags & O_TRUNC) {
+	if ((status = mdb_drop(txn, dbi, 0)))
+	    msg_fatal("truncate %s: %s", mdb_path, mdb_strerror(status));
+    } else {
+	mdb_txn_abort(txn);
+	txn = NULL;
+    }
+
+    dict_lmdb = (DICT_LMDB *) dict_alloc(DICT_TYPE_LMDB, path, sizeof(*dict_lmdb));
+    dict_lmdb->dict.lookup = dict_lmdb_lookup;
+    dict_lmdb->dict.update = dict_lmdb_update;
+    dict_lmdb->dict.delete = dict_lmdb_delete;
+    dict_lmdb->dict.sequence = dict_lmdb_sequence;
+    dict_lmdb->dict.close = dict_lmdb_close;
+    dict_lmdb->dict.lock = dict_lmdb_lock;
+    dict_lmdb->dict.stat_fd = open(mdb_path, O_RDONLY);
+    if (fstat(dict_lmdb->dict.stat_fd, &st) < 0)
+	msg_fatal("dict_lmdb_open: fstat: %m");
+    dict_lmdb->dict.mtime = st.st_mtime;
+    dict_lmdb->dict.owner.uid = st.st_uid;
+    dict_lmdb->dict.owner.status = (st.st_uid != 0);
+
+    /*
+     * Warn if the source file is newer than the indexed file, except when
+     * the source file changed only seconds ago.
+     */
+    if ((dict_flags & DICT_FLAG_LOCK) != 0
+	&& stat(path, &st) == 0
+	&& st.st_mtime > dict_lmdb->dict.mtime
+	&& st.st_mtime < time((time_t *) 0) - 100)
+	msg_warn("database %s is older than source file %s", mdb_path, path);
+
+    close_on_exec(dict_lmdb->dict.stat_fd, CLOSE_ON_EXEC);
+    dict_lmdb->dict.flags = dict_flags | DICT_FLAG_FIXED;
+    if ((dict_flags & (DICT_FLAG_TRY0NULL | DICT_FLAG_TRY1NULL)) == 0)
+	dict_lmdb->dict.flags |= (DICT_FLAG_TRY0NULL | DICT_FLAG_TRY1NULL);
+    if (dict_flags & DICT_FLAG_FOLD_FIX)
+	dict_lmdb->dict.fold_buf = vstring_alloc(10);
+    dict_lmdb->env = env;
+    dict_lmdb->dbi = dbi;
+
+    /* Save the write txn if we opened with O_TRUNC */
+    dict_lmdb->txn = txn;
+
+    dict_lmdb->cursor = 0;
+    dict_lmdb->key_buf = 0;
+    dict_lmdb->val_buf = 0;
+
+    myfree(mdb_path);
+
+    return (DICT_DEBUG (&dict_lmdb->dict));
+}
+
+#endif
diff --git a/postfix/src/util/dict_lmdb.h b/postfix/src/util/dict_lmdb.h
new file mode 100644
index 000000000..e44fcf6b3
--- /dev/null
+++ b/postfix/src/util/dict_lmdb.h
@@ -0,0 +1,41 @@
+#ifndef _DICT_LMDB_H_INCLUDED_
+#define _DICT_LMDB_H_INCLUDED_
+
+/*++
+/* NAME
+/*	dict_lmdb 3h
+/* SUMMARY
+/*	dictionary manager interface to OpenLDAP LMDB files
+/* SYNOPSIS
+/*	#include <dict_lmdb.h>
+/* DESCRIPTION
+/* .nf
+
+ /*
+  * Utility library.
+  */
+#include <dict.h>
+
+ /*
+  * External interface.
+  */
+#define DICT_TYPE_LMDB	"lmdb"
+
+extern DICT *dict_lmdb_open(const char *, int, int);
+
+ /*
+  * XXX Should be part of the DICT interface.
+  */
+extern size_t dict_lmdb_map_size;
+extern unsigned int dict_lmdb_max_readers;
+
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Howard Chu
+/*	Symas Corporation
+/*--*/
+
+#endif
diff --git a/postfix/src/util/dict_open.c b/postfix/src/util/dict_open.c
index 0f1778574..f0dca1db7 100644
--- a/postfix/src/util/dict_open.c
+++ b/postfix/src/util/dict_open.c
@@ -229,6 +229,7 @@
 #include <dict_sdbm.h>
 #include <dict_dbm.h>
 #include <dict_db.h>
+#include <dict_lmdb.h>
 #include <dict_nis.h>
 #include <dict_nisplus.h>
 #include <dict_ni.h>
@@ -271,6 +272,9 @@ static const DICT_OPEN_INFO dict_open_info[] = {
     DICT_TYPE_HASH, dict_hash_open,
     DICT_TYPE_BTREE, dict_btree_open,
 #endif
+#if defined(HAS_LMDB) && defined(SNAPSHOT)
+    DICT_TYPE_LMDB, dict_lmdb_open,
+#endif
 #ifdef HAS_NIS
     DICT_TYPE_NIS, dict_nis_open,
 #endif