Re: 'COPY' Statement

I think it depends of your datamodel and specifically of your table constraints.

For example, if you have a table with a pk generated by a sequence, you will have to deal with it before importing into your New_DB02. But for a plain log table without constrains you can dump it an import into your "just loaded" New_DB02 without any problem.


-----Original Message-----
From: Renato Oliveira <renato.oliveira@grant.co.uk>
To: pgsql-admin@postgresql.org <pgsql-admin@postgresql.org>
Cc: Steve Fisher <steve.fisher@grant.co.uk>
Subject: [ADMIN] 'COPY' Statement
Date: Tue, 13 Apr 2010 08:42:19 +0100

Dear all,

 

I just had a thought, another one. Please the guys who have the powerful knowledge I need your help ;-)

 

Let’s suppose

I have Three  DB servers ,physical servers – let’s call them:

·        Original_DB01

·        New_DB02

·        Third_DB03

 

1 – Let’s suppose I have a PostgreSQL on ‘Original_DB01’ server with a Data Base of 162GB in size.

2 – Let’s suppose I buy a new server ‘New_DB02’ - all singing all dancing cool server, RAID10, 25GB RAM, 64Bit etc.

3 – Let’s suppose I backup the old server with pg_dump to a file “pg_dump_original_DB01”

4 – Let’s also suppose I backup the schema only from ‘Original_DB01’and restore it to ‘Third_DB03’.

5 – Straight after I backup the schema, I stop PostgreSQL on ‘Original_DB01’.

6 – Then I restore the schema to ‘Third_DB03’ and point the application to it.

7 – Let’s suppose the application can create tables and can start using the database on ‘Third_DB03’ and adding new data.

8 – Let’s suppose I restore the FULL  pg_dump file “pg_dump_original_DB01” to ‘New_DB02’

9 – Once the pg_dump has been restored to ‘New_DB02’ I can then point the application to it and data will be added to it straight away.

 

Question:

10 – Can I use ‘COPY’ statement to transfer the data from ‘Third_DB03’ to ‘New_DB02’ without ‘WIPING’ or Deleting the existing data?

I want to merge the DATA from ‘Third_DB03’ to ‘New_DB02’ without deleting the Database or the existing data on the existing database.

 

Let me explain the Idea behind this craziness.

I am using ‘Third_DB03’ because the amount of data to be transferred from it, will be minimum, and easy to and quick to ‘COPY’

 

This application has two part components (Data and Alarms)

We can get the data back in a very hard way, but without the data being in the database we can’t generate alarms.

 

I would very much appreciate all your help on this idea, please.

I would be very glad and grateful for any comments and improvements on this idea, picking the holes etc.

 

Thank you very much in advance

 

Renato

 

 

 


  Renato Oliveira
Systems Administrator
e-mail: renato.oliveira@grant.co.uk   Tel: +44 (0)1763 260811
Fax: +44 (0)1763 262410
www.grant.co.uk   Grant Instruments (Cambridge) Ltd
 
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