August 5, 2003
Igor Gaponenko
This document presents the results of study to measure the size of CDB (Condition Database of BaBar). The report consists of a number of sections illustrating various aspects of the database (its profile). To distinguish database contents created before and after new CDB deployment (October 1, 2002) the following terms are used throughout the rest of the document:
“Run 1 + 2”, “old” - these two terms refer to the old (pre-CDB) Condition/DB
“Run 3”, “new CDB” - these two terms refer to the new CDB
The current CDB includes objects created during all (“Run 1”, “Run 2” and “Run 3”) periods. Physically persistent objects created during the first two periods are stored in separate sets of Objectivity/DB databases. New CDB has persistent links onto these objects from its (new) metadata.
This table shows the number of conditions for two major classes of conditions “owned” by MASTER and IR2 CDB federations. These numbers do not include duplicate names of conditions whose detector names begin with capital letters. For example, there is just one entry for the pair of conditions:
/ifr/IfrMuMuEffP
/Ifr/IfrMuMuEffP
These two entries refer to the same “physical” condition in CDB. We have them both in the database just because BaBar has some legacy (pre-CDB) client code does not respect case sensitive names of detectors.
|
Condition Type |
# of conditions |
|---|---|
|
“Rolling Calibration” at MASTER |
36 |
|
“Regular” at MASTER |
151 |
|
“Regular” at IR2 |
327 |
|
TOTAL |
514 |
These conditions are grouped into 12 so called “sub-system” groups:
dch
dct
drc
emc
fcf
ifr
mat
orc
pep
svt
tcl
trk
In addition it may worth to mention that at the time of new CDB deployment there were 504 conditions in the old database.
Since the current implementation of CDB is based on Objectivity/DB then all its (CDB) data are stored in so called “database images” (or just “databases”). These images are files in special format created and maintained by Objectivity/DB servers and tools. The following table illustrates how CDB maps onto the “databases”. There are at least two reasons why this information may be important:
Firstly, we can use it to get an idea about the overhead imposed both by the current design and the current implementation of CDB and about an overall impact of the persistent technology itself. Compare these numbers with the “payload” table (see the corresponding section below).
Secondly, “databases” is what database managers (and sometimes regular CDB clients) have to deal with.
|
Database Type |
# of databases |
Size |
|---|---|---|
|
New CDB (“Run 3”) |
37 |
10 609 049 600 |
|
Old “Link” |
55 |
266 190 848 |
|
Old “Index” |
68 |
4 084 809 728 |
|
Old “Object” |
244 |
28 309 471 232 |
|
TOTAL |
404 |
43 269 521 408 |
The following table presents the amount of the user-defined data for two major classes of conditions produced in MASTER and IR2 CDB federations. The numbers in the table do not include the metadata or any other overhead imposed by the current design/implementation of CDB or the persistent technology itself. Just pure data visible through CDB API are shown.
|
Condition Type |
Run 1 + 2 |
Run 3 |
Run 1 + 2 + 3 |
|---|---|---|---|
|
“Rolling Calibration” at MASTER |
12 584 124 784 |
6 609 945 891 |
19 194 070 675 |
|
“Regular” at MASTER |
91 614 538 |
22 554 170 |
114 168 708 |
|
“Regular” at IR2 |
2 607 074 344 |
521 795 630 |
3 128 869 974 |
|
TOTAL |
15 282 813 666 |
7 154 295 691 |
22 437 109 357 |
This table shows the number of so called “top-level” objects visible through CDB API. The “top-level” is a term referring to those objects which have been directly registered in CDB metadata. Some of these objects may represent more complex structures forming so called “composite” objects. The table has the same format as the one showing the total amount of data. So one can easy calculate that an average object in CDB is nearly 22 KB in size.
|
Condition Type |
Run 1 + 2 |
Run 3 |
Run 1 + 2 + 3 |
|---|---|---|---|
|
“Rolling Calibration” at MASTER |
147 778 |
340 103 |
487 881 |
|
“Regular” at MASTER |
1478 |
261 |
1 739 |
|
“Regular” at IR2 |
436 334 |
82 907 |
519 241 |
|
TOTAL |
585 590 |
423 271 |
1 008 861 |
The detailed information on conditions can be found at separate documents below. To facilitate browsing the conditions are sorted according to various criteria.
A subset of "rolling calibration" conditions from MASTER
A subset of “regular” conditions from all “origins”
A subset of conditions owned by MASTER only
A subset of conditions owned by IR2 only
Subsets of conditions for each subsystem are also available here: dch dct drc emc fcf ifr mat orc pep svt tcl trk