Running Global Projects
Transaction Audit Trail
: Reading from the Database
Reading from the Database
The Daemon reads from the transaction database for just two purposes:
Program Initialisation
The program reads out of the database all input commands not in a final state (processed, timed out, cancelled) and all the owned operations and output commands and starts progressing these commands. Only unfinished commands will be read. All others will be ignored and not validated for errors.
If there are any errors found in reading the database, the daemon will not start. It will then be necessary to provide a (probably) empty database so that the daemon will start from fresh and not progress any previously running commands.
Reading Command Data
Whenever command data is needed, such as to generate an output command to send on, this data is read from the database. This is the only time that data is read from the database, except at boot up, and is done purely as an optimisation to limit the amount of memory used by the daemon.
The storage of the information in the database has the additional advantages:
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It provides the user with information on the progress of his commands, allowing him to browse the messages that have been received and persisted in this database.
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It provides the administrator with an audit trail to determine if and where a problem has occurred.
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It provides other modules of the base product with a store to deposit local administration information such as element claims. However, these commands are totally ignored by the daemon.
1974 to current year.
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