mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-12-21 08:29:39 +08:00
134 lines
4.4 KiB
Plaintext
134 lines
4.4 KiB
Plaintext
erServer demonstration implementation
|
|
(c) 2000, Vadim Mikheev and Thomas Lockhart, PostgreSQL Inc.
|
|
|
|
Version 0.1:
|
|
Replicates a master database to a single slave database.
|
|
Tested under Linux (Mandrake 7.2).
|
|
|
|
Requirements:
|
|
|
|
- PostgreSQL >= 7.0.X
|
|
A separate Makefile is required for PostgreSQL 7.0.x and earlier
|
|
- Perl5 and the PostgreSQL perl interface
|
|
- TCL and the PostgreSQL tcl interface (for demo only)
|
|
|
|
|
|
How to compile:
|
|
|
|
- make all
|
|
- make install
|
|
|
|
Scripts and libraries are installed in places which are consistant
|
|
with the way other contrib/ code is installed; underneath the core
|
|
items in a contrib/ directory.
|
|
|
|
|
|
The toolset:
|
|
|
|
MasterInit dbname
|
|
sets up structures and user-defined functions for a master
|
|
database.
|
|
|
|
SlaveInit dbname
|
|
sets up structures for a slave database. Does not include triggers,
|
|
but only bookkeeping tables.
|
|
|
|
MasterAddTable dbname table column
|
|
sets up triggers for the specified table and column. Note that this
|
|
column must be updated for replication to occur.
|
|
|
|
SlaveAddTable dbname table column
|
|
sets up bookkeeping for the specified table and column.
|
|
|
|
Replicate masterdb slavedb
|
|
actually replicate changes from a master to single slave. Note that
|
|
this must be repeated to replicate to multiple slaves, but the
|
|
bookkeeping for each slave is handled separately so each can be
|
|
updated at different times and with different sets of changes.
|
|
|
|
GetSyncID [--noverbose] slavedb
|
|
returns the last syncid the specified slave has seen. May be used
|
|
in conjunction with SyncSyncID and CleanLog using the --noverbose
|
|
option.
|
|
|
|
MasterSync masterdb syncid
|
|
registers a syncid with the specified master database. Used to
|
|
propagate replication success back to the master database.
|
|
|
|
CleanLog masterdb syncid
|
|
removes obsolete entries in the master database replication log
|
|
table up to the specified replication sequence number.
|
|
|
|
Other utilities:
|
|
|
|
PrepareSnapshot
|
|
build a file of replication information from the specified masterdb.
|
|
|
|
ApplySnapshot
|
|
use a file of replication information to apply to the specified
|
|
slavedb.
|
|
|
|
|
|
How to run a demo:
|
|
|
|
Run the InitRservTest script. It will create two local databases
|
|
'master' & 'slave' with table 'test' in them. It accepts the following
|
|
arguments:
|
|
--help
|
|
Print a usage message and quit.
|
|
--user name
|
|
Access the database with another username.
|
|
--host name
|
|
Access a remote database. Note that the shared library *must* be
|
|
visible in the same path as installed on the build machine.
|
|
masterdb
|
|
slavedb
|
|
Names of test databases. Defaults to 'master' and 'slave',
|
|
respectively.
|
|
|
|
Once the test databases are set up, simply updating the master table
|
|
is sufficient to log a replication event. You can update the table
|
|
test then run "Replicate master slave", or you can use the demo
|
|
program RservTest.
|
|
|
|
Run the tcl/tk GUI demo program, RservTest. It has a single window,
|
|
which has four buttons and three data entry boxes.
|
|
|
|
--------------------------------------------------
|
|
| PostgreSQL Asynchronous Replication |
|
|
| Master Slave |
|
|
| < master > < slave > |
|
|
| |
|
|
| [ Update ] < > |
|
|
| [ Replicate ] |
|
|
| [ Show ] ____________ |
|
|
| |
|
|
| [ Quit ] |
|
|
| |
|
|
--------------------------------------------------
|
|
|
|
The demo has the following behaviors:
|
|
|
|
If you enter a string into the data entry field to the right of
|
|
[Update], then that string will be used to either update the master
|
|
database or to query the slave database.
|
|
|
|
If you click [Update], then the string in the data entry box will be
|
|
entered into the master database.
|
|
|
|
If you click [Replicate], then all changes since the last replication
|
|
will be propagated to the slave database.
|
|
|
|
If you click [Show], then the slave database will be queried to find
|
|
the string in the data entry box to the right of the [Update]
|
|
button. If the string does not (yet) exist in the slave database, then
|
|
"n/a" will appear to the right of the [Show] button. If the string
|
|
does exist in the slave database, then it will be printed to the right
|
|
of the [Show] button.
|
|
|
|
|
|
Todo:
|
|
1. Support for multiple slave servers.
|
|
2. Explicit support for master/slave failover.
|
|
3. More docs.
|