1. Off-line weekly meeting
Progress with the DB access classes
Summary:
Changes/upgrades of the classes
hunts for memory leaks
correction of a few bugs
first experience with Grid services
Weekly meeting
Alberto Colla
Alberto Colla
Off-line weekly meeting
Cern, June 30, 2005

2. Off-line weekly meeting
Reference documents
Draft note on the condition DB access, distributed to the Off-line mailing list
Talks by M. Gruwe and A. Colla at the last Alice off-line week (May 31th)
Alberto Colla
Off-line weekly meeting

3. Off-line weekly meeting
DB access classes schema
AliRunData
DB object
AliObjectMetaData
AliRunDataStorage
AliRunDataFile
AliRunDataOganizedFile
AliRunDataAlien
Local file
Local file in a defined folder structure
AliEn file
AliRunLoader
(AliSelectionMetaData)
User code
GetRunObject
Get/Put
GetEntry/PutEntry
Note: classes names are under discussion and are subject to change!
Alberto Colla
Off-line weekly meeting

4. Off-line weekly meeting
Review of the DB access classes
Following the many feedbacks received after the distribution of the note, we have reviewed the DB access classes
Changes have applied on:
the names of the DB classes
their behaviour
Alberto Colla
Off-line weekly meeting

5. Off-line weekly meeting
Renaming of the DB access classes
First of all, we were asked to change the AliRunData prefix into AliCDB. Therefore:
AliRunData  AliCDBEntry
AliRunDataStorage  AliCDBStorage
AliRunDataFile  AliCDBDump
AliRunDataOrganizedFile  AliCDBLocal
AliRunDataAlien  AliCDBGrid
Alberto Colla
Off-line weekly meeting

6. Off-line weekly meeting
DB access classes schema (New)
AliCDBEntry
DB object
AliObjectMetaData
AliCDBStorage
AliCDBDump
AliCDBLocal
AliCDBGrid
Dump file
Local file in a defined folder structure
AliEn file
AliRunLoader
(AliSelectionMetaData)
User code
GetRunObject
Get/Put
GetEntry/PutEntry
Alberto Colla
Off-line weekly meeting

7. Off-line weekly meeting
Changes in the classes’ behaviour
In case of presence of more than 1 object valid for a given run and with the same version, f.e.:
/DBFolder/ObjName/Run1-10_v0.root
/DBFolder/ObjName/Run1-15_v0.root
(Note: this can only happen if the file name is changed by hand!)
 Before: warning message, the first object found was returned
 Now: error message, no objects returned!
In case the specified version of the object to be retrieved does not exist
 Before: warning message, the closest preceding version was returned
 Now: error message, no objects returned!
Alberto Colla
Off-line weekly meeting

8. Off-line weekly meeting
Changes in the classes’ behaviour (2)
During the storage of an object with the AliCDBLocal class the run validity and version of the object’s metadata is not reset (as it was before).
If the file name is changed by hand so that the run validity and/or version do not match those in the object’s metadata a warning message is issued during retrieval.
Alberto Colla
Off-line weekly meeting

9. Off-line weekly meeting
Hunt for memory leaks
With the help of Paul Nilsson and of his SPD calibration objects I have checked the code against possible memory leaks during storage and retrieval of a large number of objects
memory leaks in the DB access classes’ code were found and corrected
a few bugs in the code were found in parallel and corrected
After the corrections we have re-checked the code by storing and getting back thousands of SPD calibration objects, with no appreciable memory leaks
Note: a SPD calibration object is a “AliITSBadChannelsSPD” container which contains a (TObj)Array of TObjArrays (one for each SPD module), in which the coordinates of the noisy channels of every SPD module are stored.
Alberto Colla
Off-line weekly meeting

10. Off-line weekly meeting
Next release of the DB access classes
Upgraded DB access classes have been sent to Peter in order to be included in the next release of AliRoot
Alberto Colla
Off-line weekly meeting

11. Off-line weekly meeting
First experience with Grid services
Reference documents:
Talks by L. Betev and A. Peters at the last Alice off-line meeting (June 01st and 02nd)
Alberto Colla
Off-line weekly meeting

12. Off-line weekly meeting
Installation of gShell and AliEn client
CERN desktop (AFS): no need to install AliEn client, install gShell V1.0.3
After installation:
laptop (no AFS): installation of AliEn client
 I tried it, but I could not connect due to problems with my certificate transferral. Will check together with Latchezar…
Alberto Colla
Off-line weekly meeting

13. Off-line weekly meeting
Installation of Root AliEn support
AliEn support configuration requires loading of gShell environment, so that $GSHELL_ROOT is defined
# cd $ROOTSYS
# ./configure –enable-alien
--with-alien-incdir=$GSHELL_ROOT/include
--with-alien-libdir=$GSHELL_ROOT/lib/
# make
Alberto Colla
Off-line weekly meeting

14. Off-line weekly meeting
Connecting to Grid from Root
Alberto Colla
Off-line weekly meeting

15. “alien://aliendb4.cern.ch:9000”, “colla”
Connecting to Grid from Root (2)
url
user
“alien://aliendb4.cern.ch:9000”, “colla”
grid
host
port
When TGrid::Connect is called:
the library $ROOTSYS/lib/libRAliEn.so is loaded via TPluginManager class
The constructor of TAlien class is invoked
Inside TAlien constructor the “new” class $GSHELL_ROOT/include/gliteUI.h is instantiated ($GSHELL_ROOT must be defined!)
GLiteUI::Connect(fHost, fPort, fUser) is called
Alberto Colla
Off-line weekly meeting

16. Off-line weekly meeting
Copying files to Grid
to copy a local file to Grid (and vice versa):
# cp file:<localPath>/filename
Grid storage elements at Cern:
ALICE::CERN::Server
ALICE::CERN::se01
ALICE::CERN::Castor
ALICE::CERN::SOFTWARE
list of files from Grid:
ls file: or ls alien: will redirect to local or Grid paths respectively.
 Unfortunately things stop working last week, after a new development of the interface (A. Peters told me). Experts are working...
Alberto Colla
Off-line weekly meeting

17. Off-line weekly meeting
Next steps
As soon as AliEn services are fully operational again:
Begin implementation of the DB access classes to Grid (AliCDBGrid)
Begin the implementation of the access classes “manager” (in order to handle the storage and retrieval from different sources)
 A summer student, Boyko Yordanov, just joined the group and will work on the access classes interface. Thanks and welcome!
Alberto Colla
Off-line weekly meeting