The document describes research into co-evolving changes in the data-intensive software system OSCAR. The researchers are studying the relationship between changes to source code files and database-related files over time, as well as how developer activity and responsibilities have changed. A case study of the OSCAR system is presented, including characteristics like its duration, number of commits, files and developers. Trends in the code dimension, like shifts between file types and the growth of database-related files, and in the social dimension, like number of active developers and their activity levels, are shown. The effects of introducing persistence technologies like Hibernate and JPA are also examined.

1. Co-­‐Evolving
Changes
in
a
Data-­‐Intensive
So3ware
System
Mathieu
Goeminne,
Alexandre
Decan,
Tom
Mens
Service
de
Génie
Logiciel,
Université
de
Mons
hDp://informaIque.umons.ac.be/genlog/projects/disse
CSMR-­‐WCRE
2014
So.ware
Evolu6on
Week
-­‐
Early
Research
Achievements,
February
2014

2. Context
• FNRS
Projet
de
Recherche
“Data-­‐Intensive
So3ware
System
EvoluIon”
– Interuniversity
collaboraIon
with
Université
de
Namur
• See
also
DAHLIA
tool
demo
by
A.
Cleve
and
L.
Meurice
• Expand
empirical
MSR
research
to
include
database-­‐related
acIviIes
• Overall
goal
– Analyse
and
support
co-­‐evoluIon
between
program
code
and
database
(schema)
in
data-­‐intensive
so3ware
systems
• Approach
– Develop
generic
framework
– Implement
dedicated
analysis
and
visualisaIon
tools
– Carry
out
empirical
case
studies
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium

3. Research
QuesIons
• Code-­‐centric
focus
– RQ1:
Is
there
any
relaIon
between
how
source
code
files
and
database-­‐related
files
evolve?
– RQ2:
What’s
the
effect
of
introducing
a
parIcular
persistency
technology
(Hibernate,
JPA)?
• Social
focus
– RQ3:
How
do
developers
divide
their
work
and
how
does
this
evolve
over
Ime?
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
3

4. Case
Study:
OSCAR
• Canadian
research
network
SCOOP
– Social
Collaboratory
for
Outcome
Oriented
Primary
care
• hDp://scoop.leadlab.ca
• Open
source
tool
infrastructure
for
Electronic
Medical
Records
(EMR)
• hDp://github.com/scoophealth
• OSCAR:
EMR
system
to
improve
healthcare
– Used
in
hundreds
of
clinics
across
Canada
– Support
for
billing,
chronic
disease
management
tools,
prescripIon
module,
scheduling,
...
• Data
available
on
hDps://github.com/scoophealth/oscar.git
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
4

5. Case
Study:
OSCAR
characteris/c
value
duraIon
3,939
days
(
>
129
months)
dates
from
Nov
2002
Ill
Aug
2013
number
of
commits
18,727
number
of
disInct
files
20,718
(of
which
54%
code
files)
number
of
file
touches
93,721
number
of
disInct
developers
100
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
5

6. EvoluIon
of
OSCAR
Code
dimension
• 3-­‐Ier
web
applicaIon
wriDen
in
Java
and
JSP
Monthly
aggregated
proporIon
of
JSP
and
Java
files
100%#
90%#
80%#
70%#
60%#
50%#
40%#
30%#
jsp#
20%#
java#
10%#
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
2013-01#
2012-07#
2012-01#
2011-07#
2011-01#
2010-07#
2010-01#
2009-07#
2009-01#
2008-07#
2008-01#
2007-07#
2007-01#
2006-07#
2006-01#
2005-07#
2005-01#
2004-07#
2004-01#
2003-07#
0%#
6

7. EvoluIon
of
OSCAR
Social
Dimension
• Monthly
number
of
disInct
acIve
developers
for
OSCAR
(a3er
idenIty
merging)
25"
20"
15"
10"
5"
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
2013'01"
2012'07"
2012'01"
2011'07"
2011'01"
2010'07"
2010'01"
2009'07"
2009'01"
2008'07"
2008'01"
2007'07"
2007'01"
2006'07"
2006'01"
2005'07"
2005'01"
2004'07"
2004'01"
2003'07"
0"
7

8. EvoluIon
of
OSCAR
Code
dimension
• Growth
of
source
code
files
w.r.t.
database-­‐related
files
6000"
pure"
5000"
sql"
4000"
3000"
2000"
1000"
2013)01"
2012)07"
2012)01"
2011)07"
2011)01"
2010)07"
2010)01"
2009)07"
2009)01"
2008)07"
2008)01"
2007)07"
2007)01"
2006)07"
2006)01"
2005)07"
2005)01"
2004)07"
2004)01"
2003)07"
0"
sql
=
code
files
containing
embedded
SQL
statements
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
8

9. EvoluIon
of
OSCAR
Social
Dimension
Developer
• How
does
the
acIvity
of
developers
evolve
over
Ime?
monthly
aggregated
number
of
file
touches
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
9

10. Introducing
Persistence
Provider
in
OSCAR
• Hibernate
– introduced
in
OSCAR
since
July
2006
– Java
object-­‐relaIonal
mapping
(ORM)
library
• XML
files
map
Java
classes
to
database
tables
and
Java
data
types
to
SQL
data
types
• facilitates
data
query
and
retrieval
• generates
SQL
calls
and
relieves
the
developer
from
manual
result
set
handling
and
object
conversion
• Java
Persistency
Architecture
(JPA)
– introduced
in
OSCAR
since
July
2008
– industry
standard
ORM
persistency
API
– Uses
Java
annotaIons
instead
of
XML
files
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
10

11. Introducing
Persistence
Provider
Code
dimension
SQL
=
code
file
containing
embedded
SQL
query
HIB
=
Java
file
targeted
by
Hibernate
XML
file
JPA
=
Java
file
containing
JPA
annotaIon
pure
=
code
files
not
containing
any
of
these
!
1600"
1400"
!
1200"
1000"
!
!
800"
JPA#
HIB#
600"
SQL#
pure#
400"
JPA"
200"
!
HIB"
SQL"
0"
2003)07)01"
2003)11)01"
2004)03)01"
2004)07)01"
2004)11)01"
2005)03)01"
2005)07)01"
2005)11)01"
2006)03)01"
2006)07)01"
2006)11)01"
2007)03)01"
2007)07)01"
2007)11)01"
2008)03)01"
2008)07)01"
2008)11)01"
2009)03)01"
2009)07)01"
2009)11)01"
2010)03)01"
2010)07)01"
2010)11)01"
2011)03)01"
2011)07)01"
2011)11)01"
2012)03)01"
2012)07)01"
2012)11)01"
2013)03)01"
2013)07)01"
!
2003-07-01#
2004-01-01#
2004-07-01#
2005-01-01#
2005-07-01#
2006-01-01#
2006-07-01#
2007-01-01#
2007-07-01#
2008-01-01#
2008-07-01#
2009-01-01#
2009-07-01#
2010-01-01#
2010-07-01#
2011-01-01#
2011-07-01#
2012-01-01#
2012-07-01#
2013-01-01#
2013-07-01#
100%#
90%#
80%#
70%#
60%#
50%#
40%#
30%#
20%#
10%#
0%#
Monthly
aggregated
number
of
acIve
code
files
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
11

12. Introducing
Persistence
Provider
Social
dimension
Developer
• Who
is
involved
in
introducing
changes
in
database-­‐related
code?
Bubble
size
=
log(monthly
aggregated
number
of
touched
files)
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
12

13. EvoluIon
of
OSCAR
Social
Dimension
• How
do
developers
divide
their
work?
OSCAR$developers$(100)$
3"
24"
Java$(87)$
JSP$(86)$
24"
10"
HIB$
1"
9"
8"
10"
JPA$
11"
0"
SQL$(53)$
Number of developers that introduce database-related code
in some file for the first time
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
13

14. Preliminary
Conclusions
RQ1:
Code-­‐related
and
database-­‐related
files
evolve
together
(no
“phased”
co-­‐evoluIon)
!
RQ2:
IntroducIon
of
Hibernate,
then
JPA
which
takes
over
Hibernate,
but
embedded
SQL
sIll
remains
very
important
!
!
RQ3:
No
clear
separaIon
of
acIviIes
between
developers
Majority
of
developers
changes
both
db-­‐related
and
db-­‐
unrelated
code
No
observed
periods
dedicated
to
a
specific
acIvity
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
14

15. Future
work
• Analyse
file
changes
at
finer
granularity
• Link
code-­‐centric
view
with
database-­‐centric
view
– Who
is
making
changes
in
the
database
schema?
– How
do
schema
changes
relate
to
(and
impact)
code
changes
(and
vice
versa)?
– Which
co-­‐evoluIon
change
paDerns
do
we
observe?
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
15

16. Future
Work
• Study
impact
of
using
ORM
providers
– Analyse
introducIon
of
new
technology
in
code
• Do
we
observe
parIcular
refactorings?
– How
do
persistence
providers
reduce
impact
of
changes
in
database
schema?
• Replicate/generalise
study
on
other
systems
– SuggesIons?
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
16

17. References
• M.
Goeminne,
A.
Decan,
T.
Mens,
Co-­‐evolving
Code-­‐
Related
and
Database-­‐Related
Changes
in
a
Data-­‐Intensive
So.ware
System,
CSMR-­‐WCRE
2014
ERA
track
• L.
Meurice,
A.
Cleve,
DAHLIA:
A
Visual
Analyzer
of
Database
Schema
Evolu6on,
CSMR-­‐WCRE
2014
Tool
Demo
• A.
Cleve,
T.
Mens,
J.-­‐L.
Hainaut,
Data-­‐Intensive
System
EvoluIon,
IEEE
Computer
43(8):
110-­‐112
(2010)
• A.
Cleve,
M.
Gobert,
L.
Meurice,
J.
Maes,
J.
Weber,
Understanding
database
schema
evoluIon:
A
case
study,
Science
of
Computer
Programming
(2013)
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
17

18. References
!
!
Evolving Software Systems
Mens, Tom; Serebrenik, Alexander; Cleve, Anthony (Eds.)
2014, XXIII, 404 p.
!
Springer, ISBN 978-3-642-45398-4
February
2014
-­‐
CSMR-­‐WCRE
So3ware
EvoluIon
Week,
Antwerp,
Belgium
18