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Overview
This document should get you up and running with a replicated PostgreSQL database in just a few steps. We'll gloss over many details in the interest of getting you up and running as quickly as possible. To make things simple, this document will use the sample cluster configuration found in the "bruce/sample"
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directory
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of
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the
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distribution.
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The
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example
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uses
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a
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single
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PostgreSQL
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installation
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with
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4
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databases.
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bruce_config
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- -
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- This
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- database
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- contains
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- the
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- cluster
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- configuration
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- metadata.
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- This
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- includes
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- cluster
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- names
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- and
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- identifiers,
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- master
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- database
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- uri's
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- and
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- descriptive
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- names,
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- slave
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- database
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- uri's
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- and
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- descriptive
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- names,
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- and
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- regular
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- expression
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- patterns
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- to
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- determine
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- which
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- tables
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- are
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- replicated.
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bruce_master
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- -
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- The
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- master
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- database.
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- All
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- modifications
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- to
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- replicated
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- tables
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- are
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- made
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- to
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- this
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- database
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- and
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- subsequently
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- replicated
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- to
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- each
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- slave.
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bruce_slave_1
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- -
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- A
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- slave
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- database.
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- All
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- modifications
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- to
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- the
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- master
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- database
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- are
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- replicated
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- here.
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bruce_slave_2
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- -
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- A
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- slave
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- database.
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- All
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- modifications
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- to
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- the
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- master
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- database
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- are
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- replicated
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- here.
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The
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master
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and
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each
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slave
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have
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a
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replication_test
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schema
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and
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a
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replication_test.replicate_this
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table
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that
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we
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will
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replicate
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across
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the
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cluster.
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Note:
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This
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demonstration
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makes
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the
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assumption
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that
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all
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replicated
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clusters
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in
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the
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schema
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contain
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identical
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data.
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Automated Test
The steps in this guide are loosely followed in test/src/com/netblue/bruce/SetupClusterFromExistingDbAcceptanceTest.java
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Prerequisites
- Download latest build: insert build link here
tar xvzf bruce-0.1a.tgz
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- Change scripts to be executable:
cd release/binchmod 755 *.sh- Ensure you have database set up properly:
- create db bruce_config
- create db bruce_master
- create db bruce_slave_1
- create db bruce_slave_2
- create user bruce with access to all databases and ability to create database objects (NB: need to think about security in real life applications)
- create schema replication_test in bruce_master, bruce_slave_1 and bruce_slave_2
- create table replication_test.replicate_this
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- in
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- bruce_master,
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- bruce_slave_1
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- and
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- bruce_slave_2
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Configure
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the
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node
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topology
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database
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urls:
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cd $BRUCE/sample
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vi config.xml
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- (change
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- db
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- urls
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- to
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- point
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- to
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- your
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- databases
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- for
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- each
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- node)
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Setup
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the
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node
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topology
cd $BRUCE/bin
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./admin.sh
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-data
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../sample/config.xml
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-initnodeschema
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-initsnapshots
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MASTER
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-loadschema
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-operation
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CLEAN_INSERT
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-url
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jdbc:postgresql://localhost:5432/bruce_config?user=bruce
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-pass
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bruce
Command line notes:
-data ../sample/config.xml
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tells
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us
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what
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data
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file
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to
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load.
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the
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sample
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file
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contains
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1
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master
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and
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2
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slaves
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with
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replication
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patterns
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to
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recognize
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the
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replication_test.*
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tables.
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-initnodeschema
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tells
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us
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to
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install
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the
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replication
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schema
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on
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each
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node,
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along
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with
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the
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triggers
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for
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each
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replicated
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table.
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If
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the
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schema
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is
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already
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installed,
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then
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only
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the
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replication
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triggers
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are
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installed
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for
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each
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replicated
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table.
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For
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master
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nodes,
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if
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there
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is
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no
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data
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in
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the
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snapshotlog
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table
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(as
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in
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this
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case)
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a
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snapshot
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of
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the
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db
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is
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taken.
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-initsnapshots
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MASTER
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tells
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us
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to
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set
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the
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slave
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snapshot
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status
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to
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the
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last
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snapshot
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in
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the
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master
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database.
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Since
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the
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-initnodeschema
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option
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initializes
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this
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for
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us,
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we'll
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use
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that.
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-loadschema
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tells
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us
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to
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install
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the
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replication
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node
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topology
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schema
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on
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the
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configuration
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database.
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This
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is
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only
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really
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useful
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the
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first
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time
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you
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run
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the
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admin
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tool
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for
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a
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given
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configuration
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database.
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-operation
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CLEAN_INSERT
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tells
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us
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to
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drop
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everything
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from
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the
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node
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topology
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configuration
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database
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before
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inserting
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these
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new
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nodes
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-url
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is
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the
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URL
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for
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the
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configuration
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database
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-pass
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is
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the
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password
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for
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the
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configuration
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database
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Start
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up
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replication
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for
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the
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new
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cluster
- cd $BRUCE/bin
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- ./startup.sh
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- ClusterOne
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Insert
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rows
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in
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master,
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confirm
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slave
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is
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updated
- psql bruce_master
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- insert into replication_test.replicate_this
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- (name,
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- value)
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- values
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- ('One',
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- 1);
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- \c
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- bruce_slave_1
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- select * from replication_test.replicate_this
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- \c
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- bruce_slave_2
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- select * from replication_test.replicate_this
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