The Chimera Virtual Data System
www.griphyn.org/chimera
Presented by Mike Wilde
Workflow Workshop
3 December 2003
e-Science Institute, Edinburgh
Acknowledgements
GriPhyN – the Grid Physics Network –
is supported by The National Science Foundation,
Information Technology Research Program
The Chimera Virtual Data System
is the work of Ian Foster, Jens Voeckler, Mike Wilde
and Yong Zhao
The Pegasus Planner is the work of Ewa Deelman,
Gaurang Mehta, and Karan Vahi
This talk was also delivered at the Data Provenance and Annotation Workshop, 1 Dec 2003
3 Dec 2003
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Provenance System Goals
Producing data from transformations with uniform,
precise data interface descriptions enables…


Discovery: finding and understanding datasets and
transformations
Workflow: structured paradigm for organizing,
locating, specifying, & producing scientific datasets
– Forming new workflow
– Building new workflow from existing patterns
– Managing change

Planning: automated to make the Grid transparent

Audit: explanation and validation via provenance
3 Dec 2003
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Virtual Data Grid Vision
virtual
data
catalog
discovery
discovery
request planner
request executor
(Condor-G,
GRAM)
request
predictor
(Prophesy)
Grid Monitor
Grid
Operations
3 Dec 2003
replica location
service
storage
element
t
da
a
detector
storage
element
Data Grid
simulation data
analysis
workflow
executor
(DAGman)
storage
element
simulation
g
nin
workflow
planner
virtual
data
catalog
w
ra
n
io
t
a
iv
r
de
Data
Transport
Researcher
virtual data
index
Storage
Resource
Mgmt
n
pla
Production
Manager
sharing
composition
Science
Review
virtual
data
catalog
Computing Grid
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Virtual Data Example:
Galaxy Cluster Search
DAG
Sloan Data
Galaxy cluster
size distribution
100000
Number of Clusters
10000
1000
100
10
1
1
Jim Annis, Steve Kent, Vijay Sehkri,
Fermilab, Michael Milligan, Yong Zhao,
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7
University of Chicago
10
Number of Galaxies
3 Dec 2003
100
Virtual Data Application:
High Energy Physics
Data Analysis
mass = 200
decay = bb
mass = 200
mass = 200
decay = ZZ
mass = 200
decay = WW
stability = 3
mass = 200
decay = WW
mass = 200
event = 8
mass = 200
plot = 1
Work and slide by
Rick Cavanaugh and
Dimitri Bourilkov,
University of Florida
3 Dec 2003
mass = 200
decay = WW
stability = 1
LowPt = 20
HighPt = 10000
mass = 200
decay = WW
stability = 1
mass = 200
decay = WW
event = 8
mass = 200
decay = WW
plot = 1
www.griphyn.org/chimera
mass = 200
decay = WW
stability = 1
event = 8
mass = 200
decay = WW
stability = 1
plot = 1
8
Provenance Scenario
psearch –t 10 …
file1
file8
simulate –t 10 …
file2
reformat –f fz …
file1
file1
File3,4,5
file7
conv –I esd –o aod…
Update
workflow
following
changes
3 Dec 2003
file6
summarize –t 10 …
Manage workflow;
Explain provenance, e.g. for file8:
On-demand
data
psearch –t 10 –i file1 file3 file4 file5 file7–o file8
generation
simulate –t 10 –o file1 file2
reformat –f fz –i file2 –o file3 file4 file5
summarize –t 10 –i file6 –o file7
conv –l esd –o aod –i file 2 –o file6
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Fundamental Units

Transformations
–
–
–
–

Interface Declarations
Action Declarations
Call declaration
Invocation
Datasets
– Contents
– Representation
– Location
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VDL: Virtual Data Language
Describes Data Transformations

Transformation
– Abstract template of program invocation
– Similar to "function definition"

Derivation
– “Function call” to a transformation
– Stores past and future:
> A record of how data products were generated
> A recipe of how data products can be generated

Invocation
– Record of a Derivation execution
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Example Transformation
TR t1( out a2, in a1, none pa = "500", none
env = "100000" ) {
argument = "-p "${pa};
$a1
argument = "-f "${a1};
argument = "-x –y";
t1
argument stdout = ${a2};
profile env.MAXMEM = ${env};
$a2
}
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Example Transformation Calls
(Derivations)
DV d1->t1 (
env="20000", pa="600",
a2=@{out:run1.exp15.T1932.summary},
a1=@{in:run1.exp15.T1932.raw},
);
DV d2->t1 (
a1=@{in:run1.exp16.T1918.raw},
a2=@{out.run1.exp16.T1918.summary}
);
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Workflow from File Dependencies
TR tr1(in a1, out a2) {
file1
argument stdin = ${a1};
argument stdout = ${a2}; }
x1
TR tr2(in a1, out a2) {
argument stdin = ${a1};
file2
argument stdout = ${a2}; }
DV x1->tr1(a1=@{in:file1}, a2=@{out:file2});
x2
DV x2->tr2(a1=@{in:file2}, a2=@{out:file3});
file3
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Example Invocation
Completion status and
resource usage
Attributes of executable
transformation
Attributes of input and output
files
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Example Workflow

preprocess
Complex structure
– Fan-in
– Fan-out
findrange
– "left" and "right" can
run in parallel
findrange

Uses input file
– Register with RC

analyze
3 Dec 2003
Complex file
dependencies
– Glues workflow
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Compound Transformations

(cont)
TR diamond encapsulates “diamond” workflows:
TR diamond( out fd, io fc1, io fc2, io fb1, io fb2, in fa, p1,
p2 ) {
call preprocess( a=${fa}, b=[ ${out:fb1}, ${out:fb2} ]
);
call findrange( a1=${in:fb1}, a2=${in:fb2},
name="LEFT", p=${p1}, b=${out:fc1} );
call findrange( a1=${in:fb1}, a2=${in:fb2},
name="RIGHT", p=${p2}, b=${out:fc2} );
call analyze( a=[ ${in:fc1}, ${in:fc2} ], b=${fd} );
}
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Compound Transformations

(cont)
Multiple DVs allow easy generator scripts:
DV d1->diamond( fd=@{out:"f.00005"},
fc1=@{io:"f.00004"}, fc2=@{io:"f.00003"},
fb1=@{io:"f.00002"}, fb2=@{io:"f.00001"},
fa=@{io:"f.00000"}, p2="100", p1="0" );
DV d2->diamond( fd=@{out:"f.0000B"},
fc1=@{io:"f.0000A"}, fc2=@{io:"f.00009"},
fb1=@{io:"f.00008"}, fb2=@{io:"f.00007"},
fa=@{io:"f.00006"}, p2="141.42135623731", p1="0" );
...
DV d70->diamond( fd=@{out:"f.001A3"},
fc1=@{io:"f.001A2"}, fc2=@{io:"f.001A1"},
fb1=@{io:"f.001A0"}, fb2=@{io:"f.0019F"},
fa=@{io:"f.0019E"}, p2="800", p1="18" );
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Dataset Requirements
<FORM
<Title…>
/FORM>
File
Set of files
Relational query or
spreadsheet range
3 Dec 2003
Object closure
XML Element
New user-defined Set of files with
dataset type:
relational index
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Possible Dataset Type Model

Types used for
– Managing dataset representation
– Determining argument conformance in
invocations
– Discovery of datasets and transformations

Two parallel type hierarchies separate
representation and semantics
– Representational: organizes and specifies
families of dataset representation
– Logical: organizes and specifies applicationspecific semantics of datasets
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Example Dataset Types
(Nonleaf Types are Superclasses)
FileDataset
File
MultiFileSet
Representational
FileSet
TarFileSet
Logical
EventCollection
RawEventSet
MonteCarlo
Simulation
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SimulatedEventSet
DiscreteEvent
Simulation
27
Dataset Representation Descriptor



Defines a dataset’s physical layout
Permits transformations to access datasets
Structure is defined by dataset type (examples)
–
–
–
–
File: <lfn>
<evt.02>
MultiFileSet: <lfn+>
<evt.03, evt.04, evt05>
TarFileSet: <lfn,taropts> <evts.1998, "-b50 -z">
Relation: <<odbc><select .*>>
<server name="db.mcs.anl.gov" db="hepdb" id="uchep"/>
<query request="select * from evt where eid>2897 and eid<3945" />


Stored in dataset catalog
Format constrained by DS type def
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Provenance Schema
Type
name=type2
repres=<...>
instance
of
Dataset
name=foo
type=type2
Contains
arguments of
Reads/writes/
creates/deletes
Transformation
Derivation
type-signature=
prog1(
in type1 X,
out type2 Y
)
instance
of
type-signature=
prog1(
in type1 fnn,
out type2 foo
)
describes
physical
replica of
Replica
locn=U.Chicago
Reads/writes/
creates/deletes
Invocation
invocation when=10am
time=20 secs
of
locn=U.Chicago
describes
Metadata
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Observations


A provenance approach based on interface
definition and data flow declaration fits well
with Grid requirements for code and data
transportability and heterogeneity
Working in a provenance-managed system
has many fringe benefits: uniformity,
precision, structure, communication,
documentation
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Vision for Provenance in the Large



Universal knowledge management and
production systems
Vendors integrate the provenance tracking
protocol into data processing products
Ability to run anywhere “in the Grid”
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Virtual Data Grid Vision
virtual
data
catalog
discovery
discovery
request planner
request executor
(Condor-G,
GRAM)
request
predictor
(Prophesy)
Grid Monitor
Grid
Operations
3 Dec 2003
replica location
service
storage
element
t
da
a
detector
storage
element
Data Grid
simulation data
analysis
workflow
executor
(DAGman)
storage
element
simulation
g
nin
workflow
planner
virtual
data
catalog
w
ra
n
io
t
a
iv
r
de
Data
Transport
Researcher
virtual data
index
Storage
Resource
Mgmt
n
pla
Production
Manager
sharing
composition
Science
Review
virtual
data
catalog
Computing Grid
www.griphyn.org/chimera
32
Systems requirements:
Services and Interfaces





Provenance databases, servers, virtual machines,
workflow composers
Provenance navigation portals and webs
Embedded tracing systems esp. within interactive
tools: SPSS, ROOT, Excel, etc
Catalog integration: replica catalogs, metadata
catalogs, transformation catalogs, integrity,
coherence, interoperability.
Interaction between provenance systems and
workflow systems
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Provenance Servers

OGSA-based Grid services
– Discovery, security, resource management




Supports code and data discovery
and workflow management
Object names (TR, DS, TY, DV, IV) can be
used as global cross-server links
Derivations can reference remote
transformations and datasets
Structured object namespaces & object-level
access control enable large VO collaboration
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Indexing Provenance Servers to
Support Discovery
Group Index
Personal
VDS
DV
Personal
Index
Personal
Index
DS
TR
Collaborationlevel
index
DV
DV
TR
DS
TR
TR
Collaboration
VDS
DV
Group VDS
DS
Personal
Index
DV
DV
Personal
VDS
Collaboration-wide
index
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Challenges

What’s the unit of change? Dataset? File? Object?
Relations to the worlds of HDF, CDF, FITS, many others
Does a dataset type have multiple dimensions?
Dataset names/handles






Unification of processing models: App, SQL,
Service
Closure and reflection: Are transformations and
workflows datasets? Can we track provenance of
annotations?
Version management: mutability, timestamps
Garbage collection, retention, pruning
Distribution: what standards and naming protocols
are needed? Catalogs, schemas?
Theoretical models? Unification of fine-grain and
coarse-grained models?
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