Hs config

MidasHistoryInterface

New history configuration defines history channels similar to logger channels. Each history channel creates a history interface class (class MidasHistoryInterface). The mlogger can use this interface to write data into the history, mhttpd, mhist & co can use this interface to read data from the history. The interface is defined in history.h

• http://ladd00.triumf.ca/~daqweb/doc/midas/include/history.h

History drivers

The MIDAS distribution contains these drivers. More drivers can be easily added by the user (create history_xxx.cxx, add constructor to hs_get_histrory(), create the ODB /Logger/History/x/channel).

• "MIDAS" is the traditional MIDAS history, data is stored in the .hst binary files. (format is documented here mhformat, see also mhist and mhdump)
• "ODBC" stores history data in SQL database using the ODBC abstraction layer. MySQL is fully supported, Pgsql support is partially implemented, support for arbitrary ODBC driver is easy to add.
• "SQLITE" stores data in SQLITE3 .sqlite3 files. The SQL table format is similar to ODBC history, performance is similar, no database server required.

ODB tree

• /Logger/
  • History/0/ --- history channel 0 (by default: "MIDAS")
    • Type --- driver type ("MIDAS")
    • Active --- y/n --- tells mlogger to write data into this channel
    • Debug --- debug level
    • PerVariableHistory --- tells mlogger to enable the Per-variable history logging mode
  • History/1/ --- history channel 1 (by default: "ODBC")
    • Type --- driver type ("ODBC")

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