rserv/doc/eRserver.HOWTO


Nélio Alves Pereira Filho
nelio@ime.usp.br

+-------------------------------------------------------------------------+
|                Como Criar um ambiente de replicação rserv               |
+-------------------------------------------------------------------------+

Antes de qualquer coisa, os arquivos contidos no pacote do rserv desta 
desta documentação devem ser copiados para seus respectivos lugares. Por 
exemplo,
/bin/* -> /usr/lib/postgresql/bin/
/share/RServ.pm -> /usr/lib/postgresql/share/contrib/
/lib/rserv.so -> /usr/lib/postgresql/lib/

A documentação dos programas extras criados encontram-se no arquivo
eRserver.Changelog.


from: http://techdocs.postgresql.org/

HOWTO: Setting up RServ with PostgreSQL 7.0.3
Last updated 13th September 2001
by S.Gopi

http://techdocs.postgresql.org/techdocs/settinguprserv.php


*** Creating the Master Database
(You can skip this if you already have one)

    createdb master

Then create whatever tables you want in this Master database (required), 
and any records you want (optional).

Let us go with pg_dump because Replication will happen only if table 
structures and record entries (if any) are similar for both master and 
slave databases at initial stage, otherwise it gives error while Replicating.

    pg_dump -d master -f master.dump


*** Creating the Slave Database

First we create the slave database then restore the table structures 
and records from the dump we created in the previous step.
    createdb slave
    psql slave

    slave=$ \i master.dump
    slave=$ \q (quit from psql)

After setting up both the Master and Slave Databases lets get into setting 
up the Replication process.


*** Setting up Replication Process

There are Four Steps you must carry out before starting Replication

    + Step 1: Initializing Master Database for Replication
    + Step 2: Initializing Slave Database for Replication
    + Step 3: Adding Tables and Columns that needs to be Replicated in 
              Master Database
    + Step 4: Adding Tables and Columns that needs to be Replicated in 
              Slave Database
      These must be same as Master Database.


Step 1: Initializing Master Database for Replication

From the Command line execute :

    /usr/lib/postgresql/bin/MasterInit master

This Process will create necessary tables and sequences used by Replication 
process in Master database.  These tables are used by the Replication process
for keeping track of replication.


Step 2: Initializing Slave Database for Replication

From the Command line execute :

    /usr/lib/postgresql/bin/SlaveInit slave

This process will create necessary tables in slave database, according to the 
author of RServ these are used for book keeping information (I don't know for 
what purpose these are used).


Step 3: Adding Tables and Columns that needs to be Replicated in Master 
        Database

From the Command line execute :

    /usr/lib/postgresql/bin/MasterAddTable master table_name column_name 

This will add necessary entries in rserv tables in master database.  Only 
tables which are added in this way will be replicated into mirror database.

You can give a specific column name in the table, there is no restriction 
on this in this version (0.1), athough the author's document says only this 
column will be replicated.  Useful Bug !!! :-) Any column changed in the 
table will be properly updated in the master database.

Repeat the above step for all the tables in master for which you want 
mirroring (real painful job)


Step 4: Adding Tables and Columns that needs to be Replicated in Slave Database

From the Command line execute :

    /usr/lib/postgresql/bin/SlaveAddTable slave table_name column_name

These tables and columns must be same as you did for master database (I don't 
know what will happen if you change something, you can test this functionality 
if you have time.  Just remember this is version 0.1 ;-))

Repeat the above step for all the tables in slave for which you want 
mirroring (another painful work)


Then what?......

You can start doing the replication now,

/usr/lib/postgresql/bin/Replicate master slave

That's it!  You have done it...  As a test, update some records in the master
database (add, modify, delete), then do the replication and check the Slave 
database, it must be a mirror of the Master.  If not check all the above 
process again and still nothing works out just email me.

Whenever You want to replicate just execute the command :

    Replicate master slave

Note:
After executing the Replicate command just ensure a "__Snapshot" file of 0 
bytes doesn't exist either in /usr/local/pgsql/bin/ or in your current 
directory.

When I checked, this file gets created only if the replication process fails 
for some reason (even if the program didn't show up any error messages, 
remember this is version 0.1)

P.S.

RServ is very easy to use once you have created the appropriate structures 
(that is the big task).RServ is just in its infancy and it may be buggy, so 
use it at your own risk.  For example, just try this :
Without doing MasterAddTable and SlaveAddTable try doing Replicate it will 
return without any error messages with no actual mirroring.

Now, do the MasterAddTable and SlaveAddTable process then try with Replicate 
this time it does replication but original entries in slave database 
(before SlaveAddTable entries) will never get updated, or some other crap 
will happen!!  Try updating some entries in master database and then 
replication you will go with surprises...

Enjoy...
1	dpavlin	1.1
2			Nélio Alves Pereira Filho
3			nelio@ime.usp.br
4
5			+-------------------------------------------------------------------------+
6			\| Como Criar um ambiente de replicação rserv \|
7			+-------------------------------------------------------------------------+
8
9			Antes de qualquer coisa, os arquivos contidos no pacote do rserv desta
10			desta documentação devem ser copiados para seus respectivos lugares. Por
11			exemplo,
12			/bin/* -> /usr/lib/postgresql/bin/
13			/share/RServ.pm -> /usr/lib/postgresql/share/contrib/
14			/lib/rserv.so -> /usr/lib/postgresql/lib/
15
16			A documentação dos programas extras criados encontram-se no arquivo
17			eRserver.Changelog.
18
19
20
21	dpavlin	1.2	from: http://techdocs.postgresql.org/
22
23			HOWTO: Setting up RServ with PostgreSQL 7.0.3
24			Last updated 13th September 2001
25			by S.Gopi
26
27			http://techdocs.postgresql.org/techdocs/settinguprserv.php
28
29	dpavlin	1.1
30
31			*** Creating the Master Database
32			(You can skip this if you already have one)
33
34			createdb master
35
36			Then create whatever tables you want in this Master database (required),
37			and any records you want (optional).
38
39			Let us go with pg_dump because Replication will happen only if table
40			structures and record entries (if any) are similar for both master and
41			slave databases at initial stage, otherwise it gives error while Replicating.
42
43			pg_dump -d master -f master.dump
44
45
46			*** Creating the Slave Database
47
48			First we create the slave database then restore the table structures
49			and records from the dump we created in the previous step.
50			createdb slave
51			psql slave
52
53			slave=$ \i master.dump
54			slave=$ \q (quit from psql)
55
56			After setting up both the Master and Slave Databases lets get into setting
57			up the Replication process.
58
59
60			*** Setting up Replication Process
61
62			There are Four Steps you must carry out before starting Replication
63
64			+ Step 1: Initializing Master Database for Replication
65			+ Step 2: Initializing Slave Database for Replication
66			+ Step 3: Adding Tables and Columns that needs to be Replicated in
67			Master Database
68			+ Step 4: Adding Tables and Columns that needs to be Replicated in
69			Slave Database
70			These must be same as Master Database.
71
72
73			Step 1: Initializing Master Database for Replication
74
75			From the Command line execute :
76
77			/usr/lib/postgresql/bin/MasterInit master
78
79			This Process will create necessary tables and sequences used by Replication
80			process in Master database. These tables are used by the Replication process
81			for keeping track of replication.
82
83
84			Step 2: Initializing Slave Database for Replication
85
86			From the Command line execute :
87
88			/usr/lib/postgresql/bin/SlaveInit slave
89
90			This process will create necessary tables in slave database, according to the
91			author of RServ these are used for book keeping information (I don't know for
92			what purpose these are used).
93
94
95			Step 3: Adding Tables and Columns that needs to be Replicated in Master
96			Database
97
98			From the Command line execute :
99
100			/usr/lib/postgresql/bin/MasterAddTable master table_name column_name
101
102			This will add necessary entries in rserv tables in master database. Only
103			tables which are added in this way will be replicated into mirror database.
104
105			You can give a specific column name in the table, there is no restriction
106			on this in this version (0.1), athough the author's document says only this
107			column will be replicated. Useful Bug !!! :-) Any column changed in the
108			table will be properly updated in the master database.
109
110			Repeat the above step for all the tables in master for which you want
111			mirroring (real painful job)
112
113
114			Step 4: Adding Tables and Columns that needs to be Replicated in Slave Database
115
116			From the Command line execute :
117
118			/usr/lib/postgresql/bin/SlaveAddTable slave table_name column_name
119
120			These tables and columns must be same as you did for master database (I don't
121			know what will happen if you change something, you can test this functionality
122			if you have time. Just remember this is version 0.1 ;-))
123
124			Repeat the above step for all the tables in slave for which you want
125			mirroring (another painful work)
126
127
128			Then what?......
129
130			You can start doing the replication now,
131
132			/usr/lib/postgresql/bin/Replicate master slave
133
134			That's it! You have done it... As a test, update some records in the master
135			database (add, modify, delete), then do the replication and check the Slave
136			database, it must be a mirror of the Master. If not check all the above
137			process again and still nothing works out just email me.
138
139			Whenever You want to replicate just execute the command :
140
141			Replicate master slave
142
143			Note:
144			After executing the Replicate command just ensure a "__Snapshot" file of 0
145			bytes doesn't exist either in /usr/local/pgsql/bin/ or in your current
146			directory.
147
148			When I checked, this file gets created only if the replication process fails
149			for some reason (even if the program didn't show up any error messages,
150			remember this is version 0.1)
151
152			P.S.
153
154			RServ is very easy to use once you have created the appropriate structures
155			(that is the big task).RServ is just in its infancy and it may be buggy, so
156			use it at your own risk. For example, just try this :
157			Without doing MasterAddTable and SlaveAddTable try doing Replicate it will
158			return without any error messages with no actual mirroring.
159
160			Now, do the MasterAddTable and SlaveAddTable process then try with Replicate
161			this time it does replication but original entries in slave database
162			(before SlaveAddTable entries) will never get updated, or some other crap
163			will happen!! Try updating some entries in master database and then
164			replication you will go with surprises...
165
166			Enjoy...