Database Reference
In-Depth Information
Clients
Servers
Grid Collector
Administrator
Replica Catalog
Fetch tag file
Load subset
Rollback
Commit
File Locator
In:
Logical name
,
Out: Physical
location
Index Builder
In: STAR tag file
Out: Bitmap index
Replica Catalog
Analysis Code
Event Catalog
In: Conditions
Out: Logical files,
event IDs
File Scheduler
In: Physical file
New query
Event iterator
Remote SRM 1
NFS, local disk
Local SRM
Remote SRM 2
(a)
1.E+04
Sample 1
Sample 2
Sample 3
Sample 4
1.E+03
1.E+02
1.E+01
1.E+00
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
Selectivity
(b)
Figure 6.20
(See color insert following page 224.) Using grid collector can
significantly speed up analysis of STAR data. (a) schematics of grid collector,
(b) speed-up using grid collector. Wu, K, J. Gu, J. Lauret, A.M. Poskanzer,
A. Shoshani, and W.-M. Zhang. 2005. Facilitating ecient selective access
from datagrids.
International Super computer Conference 2005
, Heidelberg,
Germany.
101
,
104
In Figure 6.20b, we show the observed speed-up values versus the selectivity
of the analysis task. In this case, the selectivity is defined as the fraction
of events in the data files that are selected for an analysis task. The Grid
Collector speeds up analysis tasks primarily by reducing the amount of disk
