1. PostgreSQL and the future
Aaron Thul

2. Who am I?
• Computer & Database Geek
• Formerly a Debian SysAdmin
• Presently Vice President of Technology at a
EMOL
• PostgreSQL Evangelist
• Penguicon Organizer

5. Ground rules
• Questions are good
• Arguments are bad

6. Agenda
• Big News
• New Features
• State of PostgreSQL Community
• Evil
• Profit

7. First Things First
• There is some big news

8. First Things First
• There is some big news
• PostgreSQL 8.5 is…

9. First Things First
• There is some big news
• PostgreSQL 8.5 is…
• PostgreSQL 9.0 !

10. Why 8.5 became 9.0
• Built-in log-streaming replication
• Hot standby

11. New Features

12. Streaming replication
• Warm Standby 8.x to Hot Standby
• New kinds of postmaster processes, walsenders
and walreceiver
• Thanks to Streaming Replication, lag should be
nearly zero

13. DROP IF EXISTS
• Columns
• Constraints

14. Better messages for unique violation
• Improve unique-constraint-violation error
messages to include the exact values being
complained of.

15. Deferrable Uniqueness
• Massive unique-key reassignments

16. MOVE FORWARD or BACKWARD
• MOVE {FORWARD,BACKWARD} X
• More easily move around in a curser

17. ’samehost’ and ’samenet’
• Does anyone know what HBA stands for?
• To lazy to list all the hosts on your network
• CIDR-ADDRESS

18. GRANT ALL
• Grant privileges on all existing tables
• Automatically grant privileges on all tables that
will be created in this database in the future

19. TRIGGERS on columns
• SQL-compliant triggers on columns, ie fire only
if certain columns are named in the UPDATE's
SET list
• Help resolve circular TRIGGER issues

20. Conditional TRIGGERS
CREATE TRIGGER test_u
AFTER UPDATE ON test
FOR EACH ROW
WHEN ( NEW.i <= 0 )
EXECUTE PROCEDURE test_u();

21. VACUUM FULL
• VACUUM FULL will start to behave like
CLUSTER
• Will not actually be reordering rows
• VACUUM FULL INPLACE

22. Buffers info for explain
explain ( analyze on, buffers on ) select count(*)
from pg_attribute ;
QUERY PLAN
----------------------------------------------------
----------------------
Aggregate (cost=64.70..64.71 rows=1 width=0)
(actual time=0.466..0.466 rows=1 loops=1)
Buffers: shared hit=18 read=21
-> Seq Scan on pg_attribute (cost=0.00..59.56
rows=2056 width=0) (actual time=0.002..0.301
rows=2002 loops=1)
Buffers: shared hit=18 read=21
Total runtime: 0.492 ms

23. The list goes on
• Multi-threaded pgbench
• Hinting for number of distinct values
• Machine readable EXPLAIN
• Checking password strength
• PL/pgSQL by default

24. PostgreSQL Community

25. Who makes database Software
• Oracle/SUN
• IBM
• Microsoft

26. PostgreSQL Community
• Community not company
• Growing
• International
• PostgreSQL Association
• Nothing happening with SUN/MySQL/Oracle is
hurting the PostgreSQL community

27. www.postgresql.org
• downloads
• documentation
• bug reports
• security alerts
• wiki
• support companies

28. www.pgfoundry.org
• Modules
• Programs
• Resources

29. www.planetpostgresql.org
• Project News
• Community News
• Helpful Tips / Examples

30. archives.postgresql.org
• mailing list archives back to 1997
• full text search via postgtresql 8.3
• keyword search suggestions

31. #postgresql
• irc.freenode.net
• real time help
• rtfm_please - ??help

32. PostgreSQL Community Events
• PGCon
• PostgreSQL Conference 2009 Japan
• European PGDay
• PgWest
• PgEast
• PGCon Brazil
• Local PUGs
• http://wiki.postgresql.org/wiki/Events

33. Project Management
• Core team
• Committers
• -hackers
• Roadmap
• Web team

34. Threats to PostgreSQL
• Patent attacks
• Hiring of volunteers to work on unrelated
projects

35. Evil

36. Data Types
• Just use text
▫ char/varchar/text the same under the hood
▫ avoid artificial limits
• Focus on functions
▫ Phone numbers often require string manipulation
▫ Unix timestamp vs. Date arithmetic
• Minimize typecasts

37. Take advantage of strong data typing
• CHECK limits input at column level
• ENUM limits specific values at type level
▫ Allows you to define a custom order, provides
compact storage
• DOMAIN defines a data type within constraint
boundaries
• Often outperforms JOIN on lookup tables
• Allows for simpler schema design

38. Normalization (3NF)
• All non-key columns must be directly dependent on PK
▫ Head is only dependent on the Name through the
Workgroup column

39. Surrogate Keys
• Natural Key (NK) is a CK with a natural
relationship to that row
• Surrogate Key (SK) is an artificially added
unique identifier
▫ Since they are artificial they make queries harder
to readand can lead to more joins
• Integers do not significantly improve JOIN
performance or reduce file I/O for many data
sets

40. Bareword ids
• Makes SQL less obvious to read
▫ SELECT id, id, id FROM foo, bar, baz WHERE …
▫ Makes ANSI JOIN syntax more cumbersome
JOIN foo USING (bar_id)
▫ JOIN foo ON (foo.bar_id = bar.id)
• Often resort to alias columns to add clarity,
scoping
• Some ORMs really like this (can be overridden
• Use verbose id names instead
▫ Create table actor (actor_id, full_name text);

41. Use standard definitions
• Often data has been designed in a standard way
▫ Country Code
▫ Email address
▫ Zip Code
▫ VIN
▫ SEX (ISO 5218)
• Helps eliminate short-sightedness
• Increases commonality across projects

42. Images in the database
• Replication
• Backups
• Access control
• Transactions
• OS Portability

43. Over indexing
• Indexes must be updated when data changes
occur
▫ INSERT/UPDATE/DELETE all touch indexes
▫ Some like it HOT, pg_stat_all_tables
• BitMap vs. Multi-Column Indexes
▫ Combine index on (a) and (b) in memory
▫ Index on (x,y,z) implies index on (x) and (x,y)
• Make sure indexes are used
▫ pg_stat_all_indexes

44. Covering indexes
• Creating indexes to avoid accessing data in the
table
▫ TOAST makes this less necessary
▫ Visibility information stored in the table

45. Full text indexing
• IT ROCKS!
• Add search engine style functionality to DBMS
▫ LIKE '%foo%' and LIKE '%foo' cannot use index
▫ Regex searching has similar issues
▫ Built-in tsearch functionality in 8.3+
 GIN, expensive to update, very fast for searching
 GIST, cheaper to update, not as fast for searching
• Database Specific Syntax

46. Profit

47. Lessons To Take Away
• PostgreSQL 9.0 is going to rock
• Never confuse a company with community
• Some mistakes are just to much fun to make
only once
• Never ask for directions from a two-headed
tourist!
-Big Bird

48. Thanks to
• The PostgreSQL Community!
• Robert Treat
• Hubert Lubaczewski
• More info:
▫ http://www.depesz.com/
▫ http://www.xzilla.net/

49. Questions
• Web: http://www.chasingnuts.com
• Email: aaron@chasingnuts.com
• IRC: AaronThul on irc.freenode.org
• Jabber: apthul@gmail.com
• Twitter: @AaronThul
• AIM: AaronThul