Command line reference

chameleon command [ [ --config ] [ --source ] [ --schema ]  [ --tables ] [--logid] [ --debug ] [ --rollbar-level ] ] [ --version ] [ --full ]
Option Description Default Example
--config Specifies the configuration to use in ~.pg_chameleon/configuration/. The configuration name should be the file without the extension .yml default --config foo will use the file ~.pg_chameleon/configuration/foo.yml
--source Specifies the source within a configuration file. N/A --source bar
--schema Specifies a schema configured within a source. N/A --schema schema_foo
--tables Specifies one or more tables configured in a schema. Multiple tables can be specified separated by comma. The table must have the schema. N/A --tables schema_foo.table_bar
--logid Specifies the log id entry for displaying the error details N/A --logid 30
--debug When added to the command line the debug option disables any daemonisation and outputs all the logging to the console. The keybord interrupt signal is trapped correctly. N/A --debug
--version Displays the package version. N/A --version
--rollbar-level Sets the maximum level for the messages to be sent to rolllbar. Accepted values: “critical” “error” “warning” “info” info --rollbar-level error
--full Runs a VACUUM FULL on the log tables when the run_maintenance is executed N/A --full
Command list reference
Command Description Options
set_configuration_files Setup the example configuration files and directories in ~/.pg_chameleon  
show_config Displays the configuration for the configuration --config
show_sources Displays the sourcches configured for the configuration --config
show_status Displays an overview of the status of the sources configured within the configuration. Specifying the source gives more details about that source --config --source
show_errors Displays the errors logged by the replay function. If a log id is specified then the log entry is displayed entirely --config --logid
create_replica_schema Creates a new replication schema into the config’s destination database --config
drop_replica_schema Drops an existing replication schema from the config’s destination database --config
upgrade_replica_schema Upgrades the replica schema from a an older version --config
add_source Adds a new source to the replica catalogue --config --source
drop_source Remove an existing source from the replica catalogue --config --source
init_replica Initialise the replica for an existing source --config --source
update_schema_mappings Update the schema mappings stored in the replica catalogue using the data from the configuration file. --config --source
refresh_schema Synchronise all the tables for a given schema within an already initialised source. --config --source --schema
sync_tables Synchronise one or more tables within an already initialised source. The switch --tables accepts the special name disabled to resync all the tables with replica disabled. --config --source --tables
start_replica Starts the replica process daemon --config --source
stop_replica Stops the replica process daemon --config --source
detach_replica Detaches a replica from the mysql master configuring the postgres schemas to work as a standalone system. Useful for migrations. --config --source
enable_replica Enables the replica for the given source changing the source status to stopped. It’s useful if the replica crashes. --config --source
run_maintenance Runs a VACUUM on the log tables for the given source. If is specified then the maintenance runs a VACUUM FULL --config --source --full
stop_all_replicas Stops all the running sources within the target postgresql database. --config


Create a virtualenv and activate it

python3 -m venv venv
source venv/bin/activate

Install pg_chameleon

pip install pip --upgrade
pip install pg_chameleon

Run the set_configuration_files command in order to create the configuration directory.

chameleon set_configuration_files

cd in ~/.pg_chameleon/configuration and copy the file config-example.yml` to ``default.yml.

In MySQL create a user for the replica.

CREATE USER usr_replica ;
SET PASSWORD FOR usr_replica=PASSWORD('replica');
GRANT ALL ON sakila.* TO 'usr_replica';
GRANT RELOAD ON *.* to 'usr_replica';
GRANT REPLICATION CLIENT ON *.* to 'usr_replica';
GRANT REPLICATION SLAVE ON *.* to 'usr_replica';

Add the configuration for the replica to my.cnf. It requires a MySQL restart.

binlog_format= ROW
log-bin = mysql-bin
server-id = 1

In PostgreSQL create a user for the replica and a database owned by the user

CREATE USER usr_replica WITH PASSWORD 'replica';
CREATE DATABASE db_replica WITH OWNER usr_replica;

Check you can connect to both databases from the machine where pg_chameleon is installed.


mysql -p -h derpy -u usr_replica sakila
Enter password:
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 116
Server version: 5.6.30-log Source distribution

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.


For PostgreSQL

psql  -h derpy -U usr_replica db_replica
Password for user usr_replica:
psql (9.5.5)
Type "help" for help.

Check the docs for the configuration file reference. It will help you to configure correctly the connections.

Initialise the replica

chameleon create_replica_schema --debug
chameleon add_source --config default  --debug
chameleon init_replica --config default --debug

Start the replica with

chameleon start_replica --config default --source example

Check the source status

chameleon show_status --source example

Check the error log

chameleon show_errors
chameleon start_replica --config default --source example

To stop the replica

chameleon stop_replica --config default --source example

To detach the replica

chameleon detach_replica --config default --source example