Getting this error:
PG::InsufficientPrivilege: ERROR: permission denied to set parameter
"client_min_messages" to "warning" : SET client_min_messages TO
'warning' when connecting with redshift database.
enter image description here
My database.yml file setting looks like this
development:
adapter: postgresql
encoding: utf8
host: nacfhrcluster123.ctvpledrvuobs5.us-east-1.redshift.amazonaws.com
port: 5439
username: nacfhr123
password: NACFDChr12345!
database: devnacfhrdc
pool: 5
schema_search_path: 'beta'
timeout: 5000
min_messages: warning
Thank you guys for your responses. I resolved the issue by adding a gem with the name 'activerecord5-redshift-adapter' in my gemfile. So you have to add below line in your gem file.
gem 'activerecord5-redshift-adapter'
And then run bundle install again.
It is important to realise that Redshift IS NOT Postgres. There are many differences.
One difference is that the available parameters are much different, the only parameters that can be set on Redshift are:
analyze_threshold_percent
datestyle
extra_float_digits
query_group
search_path
statement_timeout
wlm_query_slot_count
You will need to alter your rails connection so that is does not request this parameter to be set.
I guess that means removing min_messages: warning
I hope this will help. As far as I know there is no active records available for Redshift and it don't it make sense as well as Redshift is not a typical RDBMS.
We have similar scenario where we use ROR for front end for one of analytics and planing application.
Here is our app scenario:
Front-end : ROR
Database : mysql(OLTP)
Datawarehouse : Redshift(OLAP)
This is how data flows back and forth between ROR and Redshift.
Insert/updates from ROR to Redshift(happens very rarely).
For any operations from ROR that impacts something on data warehouse, ROR executes PSQL commands with specific query, not via active records.
SELECT from Redshift(happens frequently)
Similarly, for getting data from DW for various reason done via select query and redirection to file using PSQL command, then it import it into OLTP using myssqlimport.
Link for psql, mysqlimport tools that we use.
Comment if you have further specific followup questions.
I created a multi tenancy app with Apartment gem and rails 5. I successfully create a new tenant, but I want to seed it. When I run the seeds file it states that the seed has run for this new tenant (Seeding tenant_name tenant), but there's no data there, only on public schema.
I can see 2 schemas created on PostgreSQL db,the public and the new one, but it only populates public schema. Why?
Tried putting on seeds.rb:
Apartment::Tenant.switch!('tenant_name')
And:
if Apartment::Tenant.current == "tenant_name"...
But no good.
Anyone?
Thanks in advance!
Your approach is correct, but please make sure these:
Ensure schema_search_path in PG:
Example: database.yml should look like:
default: &default
adapter: postgresql
schema_search_path: 'public,shared_extensions'
encoding: unicode
pool: 5
prepared_statements: false
development:
<<: *default
database: your_development_db
2. For schema-specific data population, run statement inside tenant switch block:
In seed.rb, first create tenant, then switch in that tenant like this:
Apartment::Tenant.switch('tenant_name') do
# Do all stuff here inside this block
# User.create(user_attributes) will create use only inside `tenant_name` schema
end
Cheer!
I have just started to use the octopus gem with rails, i tried like for the normal case
octopus:
replicated: true
fully_replicated: false
environments:
- development
development:
shard_one:
host: localhost
adapter: postgresql
database: app_development
the above i have used for the testing purpose also the main thing is used as the controller specific, not the model specific. I put this in application controller
def select_shard(&block)
Octopus.using(:shard_two, &block)
end
and call that method in appropriate controller, so its works, but when i move to heroku i have followed this https://devcenter.heroku.com/articles/distributing-reads-to-followers-with-octopus, because i need the reads only for some controller. so in this case how can i use that follower on controller specific?
I'm refactoring some features of a legacy php application which uses multiple databases with the same structure, one per language. When an user login choose his language and then all the following connections are made with the db for that app with some code like this:
$db_name = 'db_appname_' . $_SESSION['language'];
mysql_connect(...);
mysql_select_db($db_name);
I'd like to refactor also the database, but currently it's not an option because other pieces of software should remain in production with the old structure while the new app is developed, and for some time after it's been developed.
I saw this question, but both the question and the suggested gems are pretty old and it seems that they are not working with Rails 3.
Which is the best method to achieve this behavior in my new rails 3 app? Is there any other choice that avoid me to alter the db structure and fits my needs?
Last detail: in the php app even the login information are kept in separate tables, i.e. every db has its own users table and when the user logs in it also passes a language param in the login form. I'd like to use devise for auth in the new app which likely won't work with this approach, so I'm thinking to duplicate (I know, this is not DRY) login information in a separate User model with a language attribute and a separate db shared among languages to use devise features with my app. Will this cause any issue?
EDIT:
For completeness, I ended with this yml configuration file
production: &production
adapter: mysql
host: localhost
username: user
password: secret
timeout: 5000
production_italian:
<<: *production
database: db_app_ita
production_english:
<<: *production
database: db_app_eng
and with this config in base model (actually not exactly this but this is for keeping things clear)
MyModel < AR::Base
establish_connection "production_#{session[:language]}"
...
end
use establish_connection in your models:
MyModel < AR::Base
establish_connection "db_appname_#{session[:language]}"
...
end
Use MultiConfig gem I created to make this easy.
You could specify the configs in separate file like database_italian.yml etc and then call:
ActiveRecord::Base.config_file = 'database_italian'
This way it will be much easier to maintain and cleaner looking. Just add more language db config files as you wish
Can this be done? In a single application, that manages many projects with SQLite.
What I want is to have a different database for each project my app is managing.. so multiple copies of an identically structured database, but with different data in them. I'll be choosing which copy to use base on params on the URI.
This is done for 1. security.. I'm a newbe in this kind of programming and I don't want it to happen that for some reason while working on a Project another one gets corrupted.. 2. easy backup and archive of old projects
Rails by default is not designed for a multi-database architecture and, in most cases, it doesn't make sense at all.
But yes, you can use different databases and connections.
Here's some references:
ActiveRecord: Connection to multiple databases in different models
Multiple Database Connections in Ruby on Rails
Magic Multi-Connections
If you are able to control and configure each Rails instance, and you can afford wasting resources because of them being on standby, save yourself some trouble and just change the database.yml to modify the database connection used on every instance. If you are concerned about performance this approach won't cut it.
For models bound to a single unique table on only one database you can call establish_connection inside the model:
establish_connection "database_name_#{RAILS_ENV}"
As described here: http://apidock.com/rails/ActiveRecord/Base/establish_connection/class
You will have some models using tables from one database and other different models using tables from other databases.
If you have identical tables, common on different databases, and shared by a single model, ActiveRecord won't help you. Back in 2009 I required this on a project I was working on, using Rails 2.3.8. I had a database for each customer, and I named the databases with their IDs. So I created a method to change the connection inside ApplicationController:
def change_database database_id = params[:company_id]
return if database_id.blank?
configuration = ActiveRecord::Base.connection.instance_eval { #config }.clone
configuration[:database] = "database_name_#{database_id}_#{RAILS_ENV}"
MultipleDatabaseModel.establish_connection configuration
end
And added that method as a before_filter to all controllers:
before_filter :change_database
So for each action of each controller, when params[:company_id] is defined and set, it will change the database to the correct one.
To handle migrations I extended ActiveRecord::Migration, with a method that looks for all the customers and iterates a block with each ID:
class ActiveRecord::Migration
def self.using_databases *args
configuration = ActiveRecord::Base.connection.instance_eval { #config }
former_database = configuration[:database]
companies = args.blank? ? Company.all : Company.find(args)
companies.each do |company|
configuration[:database] = "database_name_#{company[:id]}_#{RAILS_ENV}"
ActiveRecord::Base.establish_connection configuration
yield self
end
configuration[:database] = former_database
ActiveRecord::Base.establish_connection configuration
end
end
Note that by doing this, it would be impossible for you to make queries within the same action from two different databases. You can call change_database again but it will get nasty when you try using methods that execute queries, from the objects no longer linked to the correct database. Also, it is obvious you won't be able to join tables that belong to different databases.
To handle this properly, ActiveRecord should be considerably extended. There should be a plugin by now to help you with this issue. A quick research gave me this one:
DB-Charmer: http://kovyrin.github.com/db-charmer/
I'm willing to try it. Let me know what works for you.
I got past this by adding this to the top of my models using the other database
class Customer < ActiveRecord::Base
ENV["RAILS_ENV"] == "development" ? host = 'devhost' : host = 'prodhost'
self.establish_connection(
:adapter => "mysql",
:host => "localhost",
:username => "myuser",
:password => "mypass",
:database => "somedatabase"
)
You should also check out this project called DB Charmer:
http://kovyrin.net/2009/11/03/db-charmer-activerecord-connection-magic-plugin/
DbCharmer is a simple yet powerful plugin for ActiveRecord that does a few things:
Allows you to easily manage AR models’ connections (switch_connection_to method)
Allows you to switch AR models’ default connections to a separate servers/databases
Allows you to easily choose where your query should go (on_* methods family)
Allows you to automatically send read queries to your slaves while masters would handle all the updates.
Adds multiple databases migrations to ActiveRecord
It's worth noting, in all these solutions you need to remember to close custom database connections. You will run out of connections and see weird request timeout issues otherwise.
An easy solution is to clear_active_connections! in an after_filter in your controller.
after_filter :close_custom_db_connection
def close_custom_db_connection
MyModelWithACustomDBConnection.clear_active_connections!
end
in your config/database.yml do something like this
default: &default
adapter: postgresql
encoding: unicode
pool: 5
development:
<<: *default
database: mysite_development
test:
<<: *default
database: mysite_test
production:
<<: *default
host: 10.0.1.55
database: mysite_production
username: postgres_user
password: <%= ENV['DATABASE_PASSWORD'] %>
db2_development:
<<: *default
database: db2_development
db2_test:
<<: *default
database: db2_test
db2_production:
<<: *default
host: 10.0.1.55
database: db2_production
username: postgres_user
password: <%= ENV['DATABASE_PASSWORD'] %>
then in your models you can reference db2 with
class Customers < ActiveRecord::Base
establish_connection "db2_#{Rails.env}".to_sym
end
What you've described in the question is multitenancy (identically structured databases with different data in each). The Apartment gem is great for this.
For the general question of multiple databases in Rails: ActiveRecord supports multiple databases, but Rails doesn’t provide a way to manage them. I recently created the Multiverse gem to address this.
The best solution I have found so far is this:
There are 3 database architectures that we can approach.
Single Database for Single Tenant
Separate Schema for Each Tenant
Shared Schema for Tenants
Note: they have certain pros and cons depends on your use case.
I got this from this Blog! Stands very helpful for me.
You can use the gem Apartment for rails
Video reference you may follow at Gorails for apartment
As of Rails 6, multiple databases are supported: https://guides.rubyonrails.org/active_record_multiple_databases.html#generators-and-migrations
Sorry for the late and obvious answer, but figured it's viable since it's supported now.