Smalltalk
Programmer
Ing. Mariano Martínez Peck marianopeck@gmail.com

SqueakDBX
The complete and G
IN to
E T
open-source solution
Kdatabase
A R
relational
M access

SqueakDBX team
Mariano Germán
Hernán
Cassinelli
M. Peck Esteban Lorenzano Palacios

F.A.Q
Who are we?
How did it begin?
What is actually SqueakDBX?

RDBMS VS. OODB
Please, don't fight ;)

Anyway, we rather program in
objects and use RDBMS than
using Java with RDBMS
;)

Survey 1/2
How many times were you forced to use a
particular database?

Survey 2/2
Which databases?

Squeak's current situation
Only MySQL and PostgreSQL native
drivers.
Limited ODBC driver
Glorp in Squeak
only works with
PostgreSQL

We are in trouble...
Direct SQL queries: 20%
Using GLORP: 8.52%

Our goal
Direct SQL queries: 100%
Using GLORP: 100%

Our purpose

OpenDBX architecture
Oracle uses oci.h and and libmysqlclient_r.
MySQL uses mysql.h libclntsh.
It has N functions.
M functions. Common API
for all backends!!!
Examples: OCIHandleAlloc(), OCIServerAttach(),
mysql_real_connect(), mysql_server_end(),
OCISessionEnd(), etc.
mysql_real_query(), etc.
Oracle MySQL PosgreSQL Sqlite SQLServer
client client client client client
library library library library library

Why OpenDBX?
It is fast
Simple to use
Flexible
Cross platform
Asynchronous queries
Specific RDBMS features
Good documentation

Deployment and infrastructure
PC1 PC2
Squeak image
Database
OpenDBX
Database
Client Library

Smalltalk and C
Squeak image
|
OpenDBX
#include <stdio.h>
#include <stdio.h>
static int mysql_odbx_get_option( odbx_t*)
static int mysql_odbx_get_option( odbx_t*)
switch( option )
switch( option )
.....
.....

Smalltalk-C Connector
FFI (Foreign Function Interface)
Main problem: Locks the entire VM

Squeak ODBC driver queries
VM locked
time

OpenDBX Connector
FFI (Foreign Function Interface)
Main problem: Locks the entire VM
Our solution:
✔ Asynchronous queries
✔ “Mini” VM locks
✔ Retry schema
✔ DBXQuerySettings>>timeout:

SqueakDBX queries
VM locked
time

Database access in Smalltalk
SqueakDBX Smalltalk driver
✔ One for all databases ✗ One for each database
✔ Less time and effort ✗ More time and effort
✔ Good performace ✗ Performance issues?
✔ OSS and proprietary ✗ Only OSS
✗ Difficult to debug ✔ Easier to debug
✗ Platform dependent ✔ Platform independent
✗ FFI locks the VM ✔ Non-locking

SqueakDBX design
SqueakDBX Structure (API)
SqueakDBX Structure (API)
SqueakDBX Platform
SqueakDBX Platform
OpenDBX Connector
OpenDBX Connector
{
{
DBXConnection
DBXConnectionSettings
DBXResultSet
DBXPlatform
DBXResult
DBXSpecialOptions
DBXRow
DBXErrorSeverity
...
DBXTimeSpec
...
FFI
FFI SqueakDBXPlugin
SqueakDBXPlugin
OpenDBX

Showtime

Who can use SqueakDBX?
An application
Glorp
Magritte-RDB
SqueakSave
Moe

Current backends and OS

Benchmark for PostgreSQL
1800
1600
1400
1200
1000
ms
800 SqueakDBX
Native
600
400
200
0
Converted Insert Select1000
Insert Select100
tests

Benchmark for MySQL
700
600
500
400
ms
300 SqueakDBX
Native
200
100
0
Converted Insert Select1000
Insert Select100
tests

Features
Mini VM locks
SqueakDBXPlugin
Automatic fields conversion
Configurable logging/trace
Special RDBMS features
Multistatements
Automatic release of resources

What do we have?
Enough unit tests
Acceptable test coverage
SmallLint runs
Good enough design
GLORP integration

Documentation
Website
Documented code
Mailing list
Benchmarks

What will come
Complete Glorp refactor and integration
More backends in more OS
Large objects support
Better SPs and functions support
Continue with SqueakDBXPlugin
Try Alien FFI
Port to Smalltalk/X ?

Glorp progress
Port from Squeak to Pharo
First refactor to SqueakDatabaseAccesor
Driver for native driver
Driver for SqueakDBX (PostgreSQL)

Glorp before SqueakDBX

Glorp after SqueakDBX

Special thanks to...
Norbert Sendetzky
GLORP Alan Knight
Stéphane Ducasse

aConnection execute: 'select * from questions
where has_answer = true'
Ing. Mariano Martínez Peck marianopeck@gmail.com

Thank you
very much