database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-30 11:03:19 +03:00
Code Activity

Please apply this patch to contrib/dbmirror

Browse Source 
In incorperates changes from myself and a number of contributors.

This update to dbmirror provides:

-replication of sequence operations via setval/nextval
-DBMirror.pl support for logging to syslog
-changed the names of the tables to dbmirror_*  (no quotes required)
-Support for writitng SQL statements to files instead of directly to
 a slave database
-More options for DBMirror.pl in the config files.

Steven Singer
This commit is contained in:
Bruce Momjian
2004-02-17 03:34:35 +00:00
parent 6dfb2b2517
commit 51b363ec24
4 changed files with 671 additions and 254 deletions
Download Patch File Download Diff File Expand all files Collapse all files

75
contrib/dbmirror/README.dbmirror
View File

@ -6,7 +6,7 @@ DBMirror is a database mirroring system developed for the PostgreSQL
database Written and maintained by Steven Singer(ssinger@navtechinc.com)
(c) 2001-2002 Navtech Systems Support Inc.
(c) 2001-2004 Navtech Systems Support Inc.
ALL RIGHTS RESERVED
Permission to use, copy, modify, and distribute this software and its
@ -57,7 +57,7 @@ Pending tables.
Requirments:
---------------------------------
-PostgreSQL-7.4 (Older versions are no longer supported)
-Perl 5.6(Other versions might work)
-Perl 5.6 or 5.8 (Other versions might work)
-PgPerl (http://gborg.postgresql.org/project/pgperl/projdisplay.php)
@ -81,13 +81,8 @@ PostgreSQL-7.4 Make Instructions:
You should now have a file named pending.so that contains the trigger.
Install this file in /usr/local/pgsql/lib (or another suitable location).
Install this file in your Postgresql lib directory (/usr/local/pgsql/lib)
If you choose a different location the MirrorSetup.sql script will need
to be modified to reflect your new location. The CREATE FUNCTION command
in the MirrorSetup.sql script associates the trigger function with the
pending.so shared library. Modify the arguments to this command if you
choose to install the trigger elsewhere.
2) Run MirrorSetup.sql
@ -95,7 +90,8 @@ This file contains SQL commands to setup the Mirroring environment.
This includes
-Telling PostgreSQL about the "recordchange" trigger function.
-Creating the Pending,PendingData, MirrorHost, MirroredTransaction tables
-Creating the dbmirror_Pending,dbmirror_PendingData,dbmirror_MirrorHost,
dbmirror_MirroredTransaction tables
To execute the script use psql as follows
@ -114,17 +110,34 @@ DBMirror.pl script. See slaveDatabase.conf for a sample.
The master settings refer to the master database(The one that is
being mirrored).
The slave settings refer to the database that the data is being mirrored to.
The slaveHost parameter must refer to the machine name of the slave (Either
a resolvable hostname or an IP address). The value for slave host
must match the Hostname field in the MirrorHost table(See step 6).
The slave settings refer to the database that the data is being
mirrored to.
The master user must have sufficient permissions to modify the Pending
tables and to read all of the tables being mirrored.
The slaveName setting in the configuration file must match the slave
name specified in the dbmirror_MirrorHost table.
DBMirror.pl can be run in two modes of operation:
A) It can connect directly to the slave database. To do this specify
a slave database name and optional host and port along with a username
and password. See slaveDatabase.conf for details.
The master user must have sufficient permissions to modify the Pending
tables and to read all of the tables being mirrored.
The slave user must have enough permissions on the slave database to
modify(INSERT,UPDATE,DELETE) any tables on the slave system that are being
mirrored.
B) The SQL statements that should be executed on the slave can be
written to files which can then be executed slave database through
psql. This would be suitable for setups where their is no direct
connection between the slave database and the master. A file is
generated for each transaction in the directory specified by
TransactionFileDirectory. The file name contains the date/time the
file was created along with the transaction id.
The slave user must have enough permissions on the slave database to
modify(INSERT,UPDATE,DELETE) any tables on the slave system that are being
mirrored.
4) Add the trigger to tables.
@ -153,7 +166,7 @@ The name of the host in the MirrorHost table must exactly match the
slaveHost variable for that slave in the configuration file.
For example
INSERT INTO "MirrorHost" ("HostName") VALUES ('mySlaveMachine.mycompany.com');
INSERT INTO "MirrorHost" ("SlaveName") VALUES ('backup_system');
6) Start DBMirror.pl
@ -171,7 +184,8 @@ Any errors are printed to standard out and emailed to the address specified in
the configuration file.
DBMirror can be run from the master, the slave, or a third machine as long
as it is able to access both the master and slave databases.
as it is able to access both the master and slave databases(not
required if SQL files are being generated)
7) Periodically run clean_pending.pl
clean_pending.pl cleans out any entries from the Pending tables that
@ -194,11 +208,28 @@ TODO(Current Limitations)
----------
-Support for selective mirroring based on the content of data.
-Support for BLOB's.
-Support for conflict resolution.
-Batching SQL commands in DBMirror for better performance over WAN's.
-Support for multi-master mirroring with conflict resolution.
-Better support for dealing with Schema changes.
Significant Changes Since 7.4
----------------
-Support for mirroring SEQUENCE's
-Support for unix domain sockets
-Support for outputting slave SQL statements to a file
-Changed the names of replication tables are now named
dbmirror_pending etc..
Credits
-----------
Achilleus Mantzios <achill@matrix.gatewaynet.com>
Steven Singer
Navtech Systems Support Inc.
ssinger@navtechinc.com