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Diffstat (limited to 'proto/lmdb_table')
| -rw-r--r-- | proto/lmdb_table | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/proto/lmdb_table b/proto/lmdb_table new file mode 100644 index 0000000..53a9cd9 --- /dev/null +++ b/proto/lmdb_table @@ -0,0 +1,119 @@ +#++ +# NAME +# lmdb_table 5 +# SUMMARY +# Postfix LMDB adapter +# SYNOPSIS +# \fBpostmap lmdb:/etc/postfix/\fIfilename\fR +# .br +# \fBpostmap -i lmdb:/etc/postfix/\fIfilename\fB <\fIinputfile\fR +# +# \fBpostmap -d "\fIkey\fB" lmdb:/etc/postfix/\fIfilename\fR +# .br +# \fBpostmap -d - lmdb:/etc/postfix/\fIfilename\fB <\fIinputfile\fR +# +# \fBpostmap -q "\fIkey\fB" lmdb:/etc/postfix/\fIfilename\fR +# .br +# \fBpostmap -q - lmdb:/etc/postfix/\fIfilename\fB <\fIinputfile\fR +# DESCRIPTION +# The Postfix LMDB adapter provides access to a persistent, +# memory-mapped, key-value store. The database size is limited +# only by the size of the memory address space (typically 31 +# or 47 bits on 32-bit or 64-bit CPUs, respectively) and by +# the available file system space. +# REQUESTS +# .ad +# .fi +# The LMDB adapter supports all Postfix lookup table operations. +# This makes LMDB suitable for Postfix address rewriting, +# routing, access policies, caches, or any information that +# can be stored under a fixed lookup key. +# +# When a transaction fails due to a full database, Postfix +# resizes the database and retries the transaction. +# +# Postfix table lookups may generate partial search keys such +# as domain names without one or more subdomains, network +# addresses without one or more least-significant octets, or +# email addresses without the localpart, address extension +# or domain portion. This behavior is also found with, for +# example, btree:, hash:, or ldap: tables. +# +# Unlike other flat-file Postfix databases, changes to +# an LMDB database do not trigger automatic daemon program +# restart, and do not require "\fBpostfix reload\fR". +# RELIABILITY +# .ad +# .fi +# LMDB's copy-on-write architecture provides safe updates, +# at the cost of using more space than some other flat-file +# databases. Read operations are memory-mapped for speed. +# Write operations are not memory-mapped to avoid silent +# corruption due to stray pointer bugs. +# +# Multiple processes can safely update an LMDB database without +# serializing requests through the proxymap(8) service. This +# makes LMDB suitable as a shared cache for verify(8) or +# postscreen(8) services. +# SYNCHRONIZATION +# .ad +# .fi +# The Postfix LMDB adapter does not use LMDB's built-in locking +# scheme, because that would require world-writable lockfiles +# and would violate the Postfix security model. Instead, +# Postfix uses fcntl(2) locks with whole-file granularity. +# Programs that use LMDB's built-in locking protocol will +# corrupt a Postfix LMDB database or will read garbage. +# +# Every Postfix LMDB database read or write transaction must +# be protected from start to end with a shared or exclusive +# fcntl(2) lock. A writer may atomically downgrade an exclusive +# lock to a shared lock, but it must hold an exclusive lock +# while opening another write transaction. +# +# Note that fcntl(2) locks do not protect transactions within +# the same process against each other. If a program cannot +# avoid making simultaneous database requests, then it must +# protect its transactions with in-process locks, in addition +# to the per-process fcntl(2) locks. +# CONFIGURATION PARAMETERS +# .ad +# .fi +# Short-lived programs automatically pick up changes to +# main.cf. With long-running daemon programs, Use the command +# "\fBpostfix reload\fR" after a configuration change. +# .IP "\fBlmdb_map_size (default: 16777216)\fR" +# The initial LMDB database size limit in bytes. +# SEE ALSO +# postconf(1), Postfix supported lookup tables +# postmap(1), Postfix lookup table maintenance +# postconf(5), configuration parameters +# README FILES +# .ad +# .fi +# Use "\fBpostconf readme_directory\fR" or +# "\fBpostconf html_directory\fR" to locate this information. +# .na +# .nf +# DATABASE_README, Postfix lookup table overview +# LMDB_README, Postfix OpenLDAP LMDB howto +# LICENSE +# .ad +# .fi +# The Secure Mailer license must be distributed with this software. +# HISTORY +# LMDB support was introduced with Postfix version 2.11. +# AUTHOR(S) +# Howard Chu +# Symas Corporation +# +# Wietse Venema +# IBM T.J. Watson Research +# P.O. Box 704 +# Yorktown Heights, NY 10598, USA +# +# Wietse Venema +# Google, Inc. +# 111 8th Avenue +# New York, NY 10011, USA +#-- |