Recap of some of the presentations I attended at Waza 2013.

1. Heroku waza 2013
Lessons Learned
Simon Bagreev
Twitter: @status_200
Github: semmin

2. I attended
Keynote - Michael Lopp
• Why Python, Ruby and Javascript are Slow - Alex Gaynor
• Heroku Secrets - Noah Zoske
• API VS Game: Fight! - Wesley Beary
• Predictable Failure - Ryan Smith
• Postgres: The bits you haven’t found - Peter Van Hardenberg
• Mobile is Not Different - Matt Thompson
• Everything is a Remix - Kirby Ferguson

3. liked the most
• Keynote - Michael Lopp
• Why Python, Ruby and Javascript are Slow - Alex Gaynor
• Heroku Secrets - Noah Zoske
• API VS Game: Fight! - Wesley Beary
• Predictable Failure - Ryan Smith
• Postgres: The bits you haven’t found - Peter Van Hardenberg
• Mobile is Not Different - Matt Thompson
• Everything is a Remix - Kirby Ferguson

4. postgres: 12 bits you
haven’t found
Made me realize

5. postgres: 12 bits you
haven’t found
• psql -- postgres console -- very powerful
• need to upgrade to 9.2
• tons of tools, extensions, types
• tools for monitoring, BI

6. WITH operator
Auxiliary statements for use in larger queries
WITH status_with_next AS (
SELECT *, lead(state, 1) OVER (partition by agent_uuid order by time) as next from
agent_statuses
),
oops AS (
SELECT * from status_with_next WHERE state = 'training' and next = 'captured'
)
SELECT name, count(*) as training_captures from oops join agents on agents.uuid =
agent_uuid GROUP BY name ORDER by training_captures DESC;

7. ARRAys
-- create
CREATE TABLE jobseekers (
email text,
industries integer[],
...
);
-- insert
INSERT INTO jobseekers(email, zip, industries, source, created_at, updated_at) VALUES ('
sbagreev@gmail.com', '23453', '{1,2,3}', 'EG', now(), now());
INSERT INTO jobseekers(email, zip, industries, source, created_at, updated_at) VALUES
('simon.bagreev@gmail.com', '23453', '{4,5,6}', 'EG', now(), now());
-- query by inclusion @>
SELECT email FROM jobseekers WHERE industries @> ARRAY[3,1];
-- > sbagreev@gmail.com
-- query by intersection &&
SELECT email FROM jobseekers WHERE industries && ARRAY[4];
-- > simon.bagreev@gmail.com

8. dblink
Connect to other Postgres Databases
-- add extension
CREATE EXTENSION dblink;
-- connect to the external database
SELECT dblink_connect('quasar_connection','dbname=quasar_development');
dblink_connect
----------------
OK
(1 row)
-- query remote database
SELECT * FROM dblink('quasar_connection', 'select id, email from users') AS
quasar_users(id int, email varchar(255));
id | email
----+----------------------------------------
24 | user1@gmail.com
23 | sbagreev@gmail.com
29 | simon.bagreev@gmail.com
25 | user5@employmentguide.com

9. listen / notify
Postgres’ own queueing, used to send notifications to clients
-- create listener
LISTEN USER_UPDATES;
/* send notification to listeners
can be done from trigger */
NOTIFY USER_UPDATES, 'User with id=23 just changed email';
-- on the listener
Asynchronous notification "user_updates" with payload "User with id=23 just changed
email" received from server process with PID 81016.

10. regexes
-- pattern matching
SELECT 'foo bar baz' ~ 's+baz' as matches_pattern;
-- search and replace
UPDATE jobseekers SET zip = regexp_replace(zip, '23', '45');
SELECT zip FROM jobseekers;
zip
-------
45451
45451

11. -- add extension
UUIDs
CREATE EXTENSION "uuid-ossp";
-- create table with uuid as PK
CREATE TABLE t (uuid uuid PRIMARY KEY DEFAULT uuid_generate_v4(), name text);
d t
Table "public.t"
Column | Type | Modifiers
--------+------+-------------------------------------
uuid | uuid | not null default uuid_generate_v4()
name | text |
INSERT INTO t(name) VALUES ('foo');
SELECT * FROM t;
uuid | name
--------------------------------------+------
7f7941f3-6705-4c28-8028-d1ee5e8d3b8b | foo

12. -- add extension
hstore !!!
CREATE EXTENSION hstore;
-- create applications table with custom attributes
CREATE TABLE job_applications(uuid uuid PRIMARY KEY DEFAULT uuid_generate_v4(),
attrs hstore,
company_id integer);
-- company 1 wants only name and email in their applications
INSERT INTO job_applications (company_id, attrs) VALUES (1, 'name => "Simon Bagreev", email => "
sbagreev@gmail.com"');
-- company 2 also wants address
INSERT INTO job_applications (company_id, attrs) VALUES (2, 'name => "Simon Bagreev", email =>
"sbagreev@gmail.com", address => "123 Broadwalk St"');
-- company 3 wants phone number too
INSERT INTO job_applications (company_id, attrs) VALUES (3, 'name => "Simon Bagreev", email =>
"sbagreev@gmail.com", address => "123 Broadwalk St", phone => "7570000000"');
SELECT * from job_applications;
attrs | company_id
-------------------------------------------------------------------------------------------------------------+------------
"name"=>"Simon Bagreev", "email"=>"sbagreev@gmail.com" | 1
"name"=>"Simon Bagreev", "email"=>"sbagreev@gmail.com", "address"=>"123 Broadwalk St" | 2
"name"=>"Simon Bagreev", "email"=>"sbagreev@gmail.com", "phone"=>"7570000000", "address"=>"123 Broadwalk St"| 3

13. hstore
Can add / delete keys
-- company 1 decides to add a phone number to the app
UPDATE job_applications SET attrs = attrs || 'phone=>7573518500'::hstore WHERE company_id=1;
SELECT attrs, company_id FROM job_applications;
attrs | company_id
-------------------------------------------------------------------------------------------------------------+------------
"name"=>"Simon Bagreev", "email"=>"sbagreev@gmail.com", "address"=>"123 Broadwalk St" | 2
"name"=>"Simon Bagreev", "email"=>"sbagreev@gmail.com", "phone"=>"7570000000", "address"=>"123 Broadwalk St"| 3
"name"=>"Simon Bagreev", "email"=>"sbagreev@gmail.com", "phone"=>"7570000000" | 1

14. hstore
Querying
-- what companies are using address on their application?
SELECT attrs, company_id FROM job_applications WHERE attrs ? 'address';
attrs | company_id
-------------------------------------------------------------------------------------------------------------+------------
"name"=>"Simon Bagreev", "email"=>"sbagreev@gmail.com", "address"=>"123 Broadwalk St" | 2
"name"=>"Simon Bagreev", "email"=>"sbagreev@gmail.com", "phone"=>"7573518500", "address"=>"123 Broadwalk St" | 3
-- find all applicants with address 123 Broadwalk
SELECT attrs, company_id FROM job_applications WHERE attrs @> 'address=>"123 Broadwalk St"'::hstore;
attrs | company_id
-------------------------------------------------------------------------------------------------------------+------------
"name"=>"Simon Bagreev", "email"=>"sbagreev@gmail.com", "address"=>"123 Broadwalk St" | 2
"name"=>"Simon Bagreev", "email"=>"sbagreev@gmail.com", "phone"=>"7573518500", "address"=>"123 Broadwalk St" | 3

15. HSTore
• can be indexed
• searchable

16. postgres has more to offer
• full-text search
• TOAST - store large values
• pgcrypto - encryption for your DB
• pg_stat_activity, pg_stat_statements - stats
• postGIS - geographical awesomeness
• JSON and PL/V8 -- schemaless SQL

17. heroku secrets presentation
• use --version=9.2 flag when adding Postgres addon on Heroku
• encrypt your app’s config, store it on AWS
• use multi-processed and multi-threaded servers
• dataclips! - read-only, easy-to-share quick database queries, exportable to
many formats, can export data to Google docs

18. Before / After
Questions I had going there:
• Q: Want to hear more explanations about recent “dumb routing issue”, and suggestions from
Heroku to make it “smarter”, especially on Cedar stack.
• A: Doesn’t affect Cedar multi-threaded environment
• Q: Want to learn more about multi-threading and multi-processing on Heroku (does it make
sense to do it in Rails/Heroku? If so, how?).
• A: Unicorn for multi-process, JRuby + JVM for multi-threading
• Q: When is Rails 4.0 / Ruby 2.0 will be officially supported by Heroku?
• A: Already is.
• Q: Will Heroku support multiple availability zones (US-West, Asia)?
• A: In Beta (US West, EU)

19. Before / After
Questions I had going there:
• Q: Will the SLA (99.99% uptime) be improved any time soon?
• A: Constantly working on it
• Q: Want learn more tricks for increasing performance on Heroku, and running large enterprise-
scale applications.
• A: Many-many options