Vertica is a pure Ruby library for connecting to Vertica databases. You can learn more about Vertica at http://www.vertica.com.
- Connecting, including over SSL.
- Executing queries, with results as streaming rows or buffered resultsets.
-
COPY table FROM STDINstatement to load data from your application. - The library is thread-safe as of version 0.11. However, you can only run one statement at the time per connection, because the protocol is stateful. In a multi-threaded environment, you may want to tthink about setting up a connection pool.
Installation
Add it to the Gemfile of your project:
gem 'vertica', '~> 1.0'
# gem 'vertica', git: 'git://github.com/wvanbergen/vertica.git' # HEAD version
Now, run bundle install.
Compatiblity
- Ruby 2.0 or higher is required.
- Compatibility is tested with Vertica 7.x community edition. Vertica versions 4.x, 5.x, and 6.x worked with at some point with this gem, but compatibility is no longer tested.
Usage
See the API Documentation for a full reference of the API. Examples of basic use cases are below
Connecting
The Vertica.connect methods takes keyword arguments and returns a connection
instance. For most options, the gem will use a default value if no value is provided.
connection = Vertica.connect(
host: 'db_server',
username: 'user',
password: 'password',
# ssl: false, # use SSL for the connection
# port: 5433, # default Vertica port: 5433
# database: nil, # there is only one database
# role: nil, # the (additional) role(s) to enable for the user.
# search_path: nil, # default: <user>,public,v_catalog
# timezone: nil, # the timezone for the connection to convert timestamps
# autocommit: false, # automatically commit INSERT/UPDATE/DELETE queries
# interruptable: false, # set to true to allow sessions to be interrupted.
# read_timeout: 600, # timeout in seconds when reading data
# debug: false, # print all the messages back and forth to STDOUT.
)- To close the connection when you're done with it, run
connection.close. - You can pass
OpenSSL::SSL::SSLContextin:sslto customize SSL connection options, ortrueto use the default (OpenSSL::SSL::SSLContext.new).
Running queries
You can run queries using the query method, either in buffered and
unbuffered mode. For large result sets, you probably do not want to use buffered results,
because buffering the entire result may require a lot of memory.
Get all the result rows without buffering by providing a block:
connection.query("SELECT id, name FROM my_table") do |row|
puts row['id'] # => 123
puts row['name'] # => 'Unicorn'
endNote: you can only use the connection for one query at the time. If you try to run another
query when the connection is still busy delivering the results of a previous query, a
Vertica::Error::SynchronizeError will be raised. Use buffered resultsets to prevent this
problem.
Store the result of the query method as a variable to get a buffered resultset:
result = connection.query("SELECT id, name FROM my_table")
connection.close # buffered result will be available even after closing the connection.
result.size # => 2
result.each do |row|
puts "Hello #{row['name']}, your ID is #{row['id']}."
endRows are provided as Vertica::Row instances. You can access the individial fields by
referring to their name as String or Symbol, or the index of the field in the result.
result.each do |row|
p row # => Vertica::Row[123, "Unicorn"]>
puts row['id'], row[:id], row[0] # Three times 123
puts row['name'], row[:name], row[1] # Three times 'Unicorn'
endLoading data into Vertica using COPY statements
Using the COPY FROM STDIN statement, you can load arbitrary data from your ruby script to the database.
connection.copy("COPY table FROM STDIN ...") do |stdin|
File.open('data.tsv', 'r') do |f|
begin
stdin << f.gets
end until f.eof?
end
endYou can also provide a filename or an IO object:
connection.copy("COPY table FROM STDIN ...", source: "data.csv")
File.open('file.csv') do |io|
connection.copy("COPY table FROM STDIN ...", source: io)
endFor more information, see the Vertica documentation
Interrupting sessions
connection = Vertica.connect(host: 'dbserver', ...)
Thread.new do
sleep(60)
connection.interrupt
end
begin
result = connection.query('SELECT complicated_query FROM huge_table')
rescue Vertica::Error::ConnectionError
# ...
endAbout
This package is MIT licensed. See the LICENSE file for more information.
Development
This project comes with a test suite. The unit tests in /test/unit do not need a database
connection to run, the functional tests in /test/functional do need a working
database connection. You can specify the connection parameters by copying the file
/test/connection.yml.example to /test/connection.yml and filling out the
necessary fields.
The /vagrant folder contains a Vagrantfile and a setup script to help you set up a development
database that you can run the functional test suite against. The full test suite is also run by
Travis CI against Vertica 7 CE, and against several Ruby versions.
Authors
- Matt Bauer & Jeff Smick all the hard work
- Willem van Bergen current maintainer
- Camilo Lopez contributor
- Erik Selin contributor
See also
- Website
- API Documentation
- Vertica documentation
- sequel-vertica: Sequel integration
- newrelic-vertica: NewRelic monitoring of queries
- node-vertica: node.js Vertica driver