From b5896ba9f6047e7031e2bdee0622d543e11a6734 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 6 May 2024 03:46:30 +0200 Subject: Adding upstream version 3.4.23. Signed-off-by: Daniel Baumann --- html/DB_README.html | 242 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 242 insertions(+) create mode 100644 html/DB_README.html (limited to 'html/DB_README.html') diff --git a/html/DB_README.html b/html/DB_README.html new file mode 100644 index 0000000..2064d66 --- /dev/null +++ b/html/DB_README.html @@ -0,0 +1,242 @@ + + + + + + +Postfix Berkeley DB Howto + + + + + + + +

Postfix Berkeley DB Howto

+ +

Introduction

+ +

Postfix uses databases of various kinds to store and look up +information. Postfix databases are specified as "type:name". +Berkeley DB implements the Postfix database type "hash" and +"btree". The name of a Postfix Berkeley DB database is the name +of the database file without the ".db" suffix. Berkeley DB databases +are maintained with the postmap(1) command.

+ +

Note: Berkeley DB version 4 is not supported by Postfix versions +before 2.0.

+ +

This document describes:

+ +

How to build Postfix without Berkeley +DB support even if the system comes with Berkeley DB.
+ +
How to build Postfix on systems that +normally have no Berkeley DB library.
+ +
How to build Postfix on BSD or Linux systems with multiple Berkeley DB +versions.
+ +
How to tweak performance.
+ +
Missing pthread library trouble.
+ +

+ +

Building Postfix without Berkeley +DB support even if the system comes with Berkeley DB

+ +

Note: The following instructions apply to Postfix 2.9 and later.

+ +

Postfix will normally enable Berkeley DB support if the system +is known to have it. To build Postfix without Berkeley DB support, +build the makefiles as follows:

+ +

+% make makefiles CCARGS="-DNO_DB"
+% make
+

+ +

This will disable support for "hash" and "btree" files.

+ +

Building Postfix on systems that normally have +no Berkeley DB library

+ +

Some UNIXes ship without Berkeley DB support; for historical +reasons these use DBM files instead. A problem with DBM files is +that they can store only limited amounts of data. To build Postfix +with +Berkeley DB support you need to download and install the source +code from http://www.oracle.com/database/berkeley-db/.

+ +

Warning: some Linux system libraries use Berkeley DB, as do +some third-party libraries such as SASL. If you compile Postfix +with a different Berkeley DB implementation, then every Postfix +program will dump core because either the system library, the SASL +library, or Postfix itself ends up using the wrong version.

+ +

The more recent Berkeley DB versions have a compile-time switch, +"--with-uniquename", which renames the symbols so that multiple +versions of Berkeley DB can co-exist in the same application. +Although wasteful, this may be the only way to keep things from +falling apart.

+ +

To build Postfix after you installed the Berkeley DB from +source code, use something like:

+ +

+% make makefiles CCARGS="-DHAS_DB -I/usr/local/BerkeleyDB/include" \
+    AUXLIBS="-L/usr/local/BerkeleyDB/lib -ldb"
+% make
+

+ +

Solaris needs this:

+ +

+% make makefiles CCARGS="-DHAS_DB -I/usr/local/BerkeleyDB/include" \
+    AUXLIBS="-R/usr/local/BerkeleyDB/lib -L/usr/local/BerkeleyDB/lib -ldb"
+% make
+

+ +

The exact pathnames depend on the Berkeley DB version, and on +how it was installed.

+ +

Warning: the file format produced by Berkeley DB version 1 is +not compatible with that of versions 2 and 3 (versions 2 and 3 have +the same format). If you switch between DB versions, then you may +have to rebuild all your Postfix DB files.

+ +

Warning: if you use Berkeley DB version 2 or later, do not +enable DB 1.85 compatibility mode. Doing so would break fcntl file +locking.

+ +

Warning: if you use Perl to manipulate Postfix's Berkeley DB +files, then you need to use the same Berkeley DB version in Perl +as in Postfix.

+ +

Building Postfix on BSD systems with multiple +Berkeley DB versions

+ +

Some BSD systems ship with multiple Berkeley DB implementations. +Normally, Postfix builds with the default DB version that ships +with the system.

+ +

To build Postfix on BSD systems with a non-default DB version, +use a variant of the following commands:

+ +

+% make makefiles CCARGS=-I/usr/include/db3 AUXLIBS=-ldb3
+% make
+

+ +

Warning: if you use Berkeley DB version 2 or later, do not +enable DB 1.85 compatibility mode. Doing so would break fcntl file +locking.

+ +

Warning: if you use Perl to manipulate Postfix's Berkeley DB +files, then you need to use the same Berkeley DB version in Perl +as in Postfix.

+ +

Building Postfix on Linux systems with multiple +Berkeley DB versions

+ +

Some Linux systems ship with multiple Berkeley DB implementations. +Normally, Postfix builds with the default DB version that ships +with the system.

+ +

Warning: some Linux system libraries use Berkeley DB. If you +compile Postfix with a non-default Berkeley DB implementation, then +every Postfix program will dump core because either the system +library or Postfix itself ends up using the wrong version.

+ +

On Linux, you need to edit the makedefs script in order to +specify a non-default DB library. The reason is that the location +of the default db.h include file changes randomly between vendors +and between versions, so that Postfix has to choose the file for +you.

+ +

Warning: if you use Berkeley DB version 2 or later, do not +enable DB 1.85 compatibility mode. Doing so would break fcntl file +locking.

+ +

Warning: if you use Perl to manipulate Postfix's Berkeley DB +files, then you need to use the same Berkeley DB version in Perl +as in Postfix.

+ +

Tweaking performance

+ +

Postfix provides two configuration parameters that control how +much buffering memory Berkeley DB will use.

+ +

berkeley_db_create_buffer_size (default: 16 MBytes per +table). This setting is used by the commands that maintain Berkeley +DB files: postalias(1) and postmap(1). For "hash" files, create +performance degrades rapidly unless the memory pool is O(file size). +For "btree" files, create performance is good with sorted input even +for small memory pools, but with random input degrades rapidly +unless the memory pool is O(file size).
+ +
berkeley_db_read_buffer_size (default: 128 kBytes per +table). This setting is used by all other Postfix programs. The +buffer size is adequate for reading. If the cache is smaller than +the table, random read performance is hardly cache size dependent, +except with btree tables, where the cache size must be large enough +to contain the entire path from the root node. Empirical evidence +shows that 64 kBytes may be sufficient. We double the size to play +safe, and to anticipate changes in implementation and bloat.
+ +

+ +

Missing pthread library trouble

+ +

When building Postfix fails with:

+ +

+undefined reference to `pthread_condattr_setpshared'
+undefined reference to `pthread_mutexattr_destroy'
+undefined reference to `pthread_mutexattr_init'
+undefined reference to `pthread_mutex_trylock'
+

+ +

Add the "-lpthread" library to the "make makefiles" command.

+ +

+% make makefiles .... AUXLIBS="... -lpthread"
+

+ +

More information is available at +http://www.oracle.com/database/berkeley-db/.

+ + + + -- cgit v1.2.3