Keys in the ODB /Logger/History subtree

Links

• /Logger tree
• Logging to a mySQL database
• /Logger/Channels subtree
• /Logger/SQL subtree
• MIDAS logger (mlogger)

---

/Logger/History subtree

The ODB /Logger/History subtree is a subdirectory of the ODB /Logger tree, created when the MIDAS logger utility mlogger is started for the first time. The keys will be filled with default values which users may change as required to customize their experiments.

When mlogger is started for the first time, it now creates five /Logger/History/<history-logging-channel> ODB subtrees to control the five default history-logging-channels, named for each of the default History drivers.

The keys present in each history-logging-channel are described below.

---

Example

The following example shows the /Logger/History ODB subtree after creation by mlogger (obtained using the odbedit ls command). See below for information on individual keys.

[local:midas:S]/>ls -r /Logger/History
History
    MIDAS
        Type                    MIDAS
        Active                  y
        Debug                   0
        PerVariableHistory      0
    ODBC
        Type                    ODBC
        Active                  n
        Debug                   0
        Writer_ODBC_DSN         history_writer
        Reader_ODBC_DSN         history_reader
    SQLITE
        Type                    SQLITE
        Active                  n
        Debug                   0
        Sqlite dir
    MYSQL
        Type                    MYSQL
        Active                  n
        Debug                   0
        MYSQL Writer            mysql_writer.txt
        MYSQL Reader            mysql_reader.txt
    FILE
        Type                    FILE
        Active                  n
        Debug                   0
        History dir

---

<history-logging-channel> subtrees

Each <history-logging-channel> subtree in the Logger/History subtree is created (by mlogger) to control one of the history drivers available, and named for that history driver.
Presently the five following history-logging-channel subtrees are created :

• MIDAS
• ODBC
• SQLITE
• MYSQL
• FILE

(see Example above).

By default, only one of these channels is Active.

---

Keys common to all history logging channel subtrees

The following three keys are common to all history logging channel subtrees :

Type

• Type: STRING
• Default: History driver name

Each history-logging-channel subtree contains a Type key which specifies the type of History driver for this channel.

When the subtree is created, the Type key is set to the respective History driver name, e.g.

/Logger/History/MIDAS/Type will be set to "MIDAS"

/Logger/History/ODBC/Type will be set to "ODBC"

and so on (see Example above for all five logging channels).

---

Active

• Type: BOOL
• Default: "n"

Each <history-logging-channel> subtree contains a Active key which enables or disables history logging in this channel.

By default, only the MIDAS-history logging channel will be set active, i.e. /Logger/History/MIDAS/Active will be set to "y".

Note

This key in the MIDAS subtree replaces obsolete key /Logger/WriteFileHistory

---

Debug

• Type: INT
• Default: 0

Each <history-logging-channel> subtree contains a Debug key which controls the debug level for this <history-logging-channel>. If set to 0, debugging is disabled.

Note;

This key in the ODBC subtree replaces obsolete key /Logger/ODBC_Debug

---

MIDAS subtree

This is the history-logging-channel subtree that controls MIDAS-history logging.

For those Keys common to all history-logging-channels see

• Type
• Active
• Debug

Note

By default, this logging channel will be set active.

The following section(s) describe keys unique to the MIDAS subtree :

---

PerVariableHistory

• Type: INT
• Default: 0

This key is present in this subtree only (i.e. MIDAS subtree with Type key set to "MIDAS").

The default value of 0 is intended to operate the MIDAS-history in "traditional" mode. In this mode:

• there is one history record for each equipment
• history record id is equal to the equipment id
• /History/Events and /History/Tags are not required and can be safely deleted

Note

this key replaces obsolete key /History/PerVariableHistory

---

ODBC subtree

This is the [[<history-logging-channel> subtrees| history-logging-channel subtree]] that controls ODBC-history logging.

For those Keys common to all history-logging-channels see

• Type
• Active
• Debug

Note

Debug key in this subtree replaces obsolete key /Logger/ODBC_Debug.

The following section(s) describe keys unique to the ODBC subtree:

Writer_ODBC_DSN

• Type: STRING
• Default: "history_writer"

This key is present in this subtree only (i.e. ODBC subtree with Type key set to "ODBC").

It contains the ODBC Data Source Name for writing and is used by mlogger.

Note

this key replaces obsolete key /Logger/ODBC DSN

---

Reader_ODBC_DSN

• Type: STRING
• Default: "history_reader"

This key is present in this subtree only (i.e. ODBC subtree with Type key set to "ODBC").

It contains the ODBC Data Source Name for reading, and is used by mhttpd and mhist utilities.

Note

this key replaces obsolete key /history/ODB_DSN

---

SQLITE subtree

This is the [[<history-logging-channel> subtrees| history-logging-channel subtree]] that controls SQLITE-history logging.

For those Keys common to all history-logging-channels see

• Type
• Active
• Debug

The following section(s) describe keys unique to the SQLITE subtree :

---

Sqlite dir

• Type: STRING
• Default:

This key is present in this subtree only (i.e. SQLITE subtree with Type key set to "SQLITE").

It contains the location of SQLITE database files, and is of the form "/file/system/path".

MYSQL subtree

This is the [[<history-logging-channel> subtrees| history-logging-channel subtree]] that controls MYSQL-history logging.

For those Keys common to all history-logging-channels see

• Type
• Active
• Debug

The following section(s) describe keys unique to the MYSQL subtree :

MYSQL Writer

• Type: STRING
• Default: mysql_writer.txt

This key is present in this subtree only (i.e. MYSQLSQL subtree with Type key set to "MYSQL").

It contains the name of the file ...

---

MYSQL Reader

• Type: STRING
• Default: mysql_reader.txt

This key is present in this subtree only (i.e. MYSQL subtree with Type key set to "MYSQL").

It contains the name of the file ...

---

FILE subtree

This is the [[<history-logging-channel> subtrees| history-logging-channel subtree]] that controls FILE-history logging.

For those Keys common to all history-logging-channels see

• Type
• Active
• Debug

The following section(s) describe keys unique to the FILE subtree :

History dir

• Type: STRING
• Default: ""

This key is present in this subtree only (i.e. FILE subtree with Type key set to "FILE").

It contains the name of the directory in which the FILE-history files are to be stored.