1. Postgres MySQL Bakeoff
right tool for the right job
when you have a hammer in your hand, everything looks like a nail

2. The contenders

3. SQL standard COMPLIANCE
Postgres
SQL92/99 (most of it)
subqueries, views, multi-user support, transactions, query optimization, inheritance, and arrays.
Mysql
SQL92 (some of it)
subqueries
views (mysql5)

4. SQL NON-compliance Postgres Cannot query across multiple databases
Mysql
transactions
inheritance
arrays
multiuser support
query optimization

5. Table

6. Keys
primary
m & p
foreign p
m needs innodb
multi primary keys

7. Data types Both: integer char, varchar, text Mysql only
tinytext, mediumtext
tinyint
longtext, long blog
Postgres only
boolean
timestamp

8. Sequences Postgresql yup Mysql what gives?
cause of ire when writing code to run on both

9. Platforms Postgres Won't run on Windows9x/Me, NextStep, Ultrix. Mysql
supposedly better on windows than pg.

10. Speed Postgres forks on every connection slower Optimization options
Mysql
choose the right table type
connection time 10x faster than postgres

11. Stability Postgres once apon a time.. memory leaks and ick
Now rock solid (7.4)
Mysql
unhappy with high connections per seconds (hundreds)
Random disconnects and core dumps are exceptionally rare.
proven in more high demand production environments than postgres

12. Data & Referential Integrity
Postgres
LOVES DATA INTEGRITY!
transactions, rollbacks
ON DELETE/UPATE, cascade
Mysql
basic
CHECK clause allowed, but does nothing.
InnoDB has foreign keys
MySAM allows foreign keys, but they do nothing

13. Security Mysql GRANT + REVOKE username tablename hostname Postgres
no grant/revoke for CREATE TABLE
db access by host, ident, network segment

14. Locking and Concurrency
Postgres
MultiVersion Concurrency Control (MVCC)
row level locks
reader not blocked by writer
Mysql
Table locking for ISAM/MyISAM and HEAP tables
InnoDB has row locking

15. Large Object Postgres needs lo_create then store by OID
lo_read/lo_write
Mysql
just like other fields
INSERT, UPDATE, SELECT and DELETE

16. Schema alterations Mysql Alter table (transaction gotcha)
ADD, DROP, RENAME column
CHANGE type
Postgres
ALTER TABLE, can be rolledback

17. Language support Neither handle multi char set databases Postgres
compile with –enable-locale
Mysql
not many tasks use locale

18. Future Mysql adding views competing transaction support Postgres
Improving performance speeds

19. Summary Data integrity important? use Postgres
Speed, replication important, use well tuned mysql
cheap hosting? mysql