SPEAR PV RDB Database EPICS Collaboration Meeting April 27, 2005 1

SPEAR PV RDB Database

Clemens Wermelskirchen

SPEAR PV RDB Database EPICS Collaboration Meeting April 27, 2005 2

PV Recording (HistoryLog)

The SPEAR control system is recording PV values into an Rdb database:

2070 analog readbacks, fixed periodic recording

recording rate: every 2 secondsrecording time: minimum ~ 120 msec

300 status readbacks + 3260 setpoint values, event driven recording

recording rate: 0.5 seconds (changes only)recording time: minimum ~ 5 msec

All data is recorded as float value (for now), i.e. no strings, no arrays.

SPEAR PV RDB Database EPICS Collaboration Meeting April 27, 2005 3

IOC Configuration and Bumpless Reboot Challenge

Problem:

• various ways to configure IOCs (IOC static “database”)

• generation of IOC configuration file difficult (and data always out of date)

Our approach:

• standard IOC boot procedure

• special initialization program “dbrestore” before IOCINIT

SPEAR PV RDB Database EPICS Collaboration Meeting April 27, 2005 4

IOC Reboot and “dbrestore”

dbrestore:

• has access to complete IOC static database structures

• uploads specific PV information to PVServer, which stores all information in an Rdb database always current PV configuration in database for Web view

• PVServer downloads last recorded (monitored) setpoint values from History database to dbrestore, which restores themusing static DB access

• IOC starts with restored setpoint values

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dbrestore, History Database, and History Recording Management

• Management of all PVs in History Database is done via WEB (PHP)

• After IOC has reported a new PV record for the first time, recording options and HistoryPlot display options are configured

• PVs can move between IOCs, only the PVname is relevant

• Actual information about PV is always available via WEB (includes IOCname, IOC boot time, current value)

• currently more than 40,000 PV definitions in database

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Procedure for new PV record

1. generate IOC db-file

2. boot IOC

3. dbrestore reports new PV

4. PVServer stores new PV attributes in Rdb database

5. IOC runs

6. If record field needs to be recorded, recording turned on via Web, also, attributes on how to display value in HistoryPlot are defined

7. Recording begins (assuming field is assign valid value)

8. parameter can be viewed in HistoryPlot

9. next time IOC boots, the monitored value is restored by dbrestore

SPEAR PV RDB Database EPICS Collaboration Meeting April 27, 2005 7

History Database Applications Overivew

PV and IOC configuration data

Recorded PV values

Tables:

Tables:

Database

PVServer

IOCs

dbrestore

HistoryLog

IOCs

CA monitor

PHP programs

Web Server

HistoryPlot

X-Applications

SPEAR PV RDB Database EPICS Collaboration Meeting April 27, 2005 8

SPEAR PV RDB Database EPICS Collaboration Meeting April 27, 2005 9

SPEAR PV RDB Database EPICS Collaboration Meeting April 27, 2005 10

History Data

Recorded history data:

• periodic data (every 2 seconds)

• event driven data (every 0.5 seconds, when changed)

• Periodic data older than 90 days is reduced to single data point every minute

• 8 months of data results in database files of about 70 GB

• Data is accessible through ODBC and JDBC

• Database applications are C-programs, Matlab-programs, Web-applications (PHP)

SPEAR PV RDB Database EPICS Collaboration Meeting April 27, 2005 11

Additional Rdb Databases

Additional Rdb databases:

• Event database (collects messages sent from application programs)Web interface for viewing

• Machine configuration database (not fully implemented yet)

SPEAR PV RDB Database EPICS Collaboration Meeting April 27, 2005 12

Conclusion

• Standard database and database tools are very useful, performance tuning without touching applications

• Database acts as central repository for different applications

• Two tier IOC configuration: - static configuration file - modifiable fields (like calibration data, ESLO, EOFF) from always up-to-date database (monitored)