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Storage - tab of the PmaTrendGroup object

Description:
Configuration of trends group data saving to disk.
Configurators:
The data are saved into the computer memory and on the disk. On the disk they are stored either in one disk file (cyclic file - after filling up the maximum size of this file, the oldest records are removed) or by the backup mode - the size (in time or in the number of rows or the variable size according to the specific requirements) of one backup file (the backup is represented by one disk file or by one table in the database - according to the configuration) and the number of these backup files is defined. The oldest backup is removed on reaching the number of backups and on the creation of a new backup.
Note: It is also possible to leave the size of the backup unlimited and to create new backups by calling the BackupCreate method as well.
For obtaining information about saving parameters to disk see PmaTrendGroup.GetPersistInfo method.
The data archive location can be changed dynamically during application runtime by methods Open and Close.
Use the data on the diskEnable/disable data save/read to/from the computer disk archive.
Load data from disk into memory at application launchIf the Use the data on the disk option is enabled and a non-zero number of records is set in the memory, then the latest data are read from the disk (if any have been stored) into the memory after the application is launched. Thus a certain amount of data is on the disk and in the memory in parallel. The information is entered in percentage with respect to the maximum number of records in the memory.
Delayed writing to diskOn the fast period of storing to disk (e.g. in the order of second units) it can be defined storing into the memory buffer. Each calling the Run method (RunTime) saves a record into this buffer. Moreover each N-th (N is the value specified in the configurator) storage clears the buffer and it moves all records stored there to disk. The value 1 (default) means that each calling the Run method (RunTime) is stored at the same time to disk and the buffer is not used.
Open at application launch (valid only in Read only (new records cannot be written) mode)Using this setting you can decide whether the object is opened and connected to data archive at application launch, or stays disconnected, i.e. it would be impossible to write new data and requests will be returned with no data. If it is disconnected, then the object can be opened any time later by calling the Open method. The object also can be closed in the script by calling the Close method.
Caution: if the PmaTrendGroup object needs to enable data read and write immediatelly after the application is launched of this object, then this configurator must be checked.
Storage typeStorage type selection to disk, see Trend storage technology comparison.
Database dBase backups - Saving the backups into the dBase files in selected folder. The backup is a table (*.dbf file) of the dBase database. The oldest backup (table) is deleted after the defined number of backups is saved.
Promotic binary file cyclic - Saving in the PROMOTIC binary format - in one cyclic disk file. After filling up the file by the defined number of records, the oldest records are removed on writing new records.
Database MS SQL Server cyclic - Saving in the table of the MS SQL database. After filling up the table the oldest records are removed on writing new records.
Database Oracle cyclic - Saving in the table of the Oracle database. After filling up the table the oldest records are removed on writing new records.
Database MySQL cyclic - Saving in the table of the MySQL database. After filling up the table the oldest records are removed on writing new records.
Database PostgreSQL cyclic - Saving in the table of the PostgreSQL database. After filling up the table the oldest records are removed on writing new records.
Database FireBird cyclic - Saving in the table of the FireBird database. After filling up the table the oldest records are removed on writing new records.
Database Access cyclic - Saving in the table of the Access database. After filling up the table the oldest records are removed on writing new records. The format of the *.MDB file is Access 2000.
This storage type has a limitation: If there are multiple PmaTrendGroup objects used with this storage type in the application, then there can be 63 such objects in one application at the most.
Database MS SQL Server backups (obsolete) - Saving in the backup mode into the MS SQL database. The backup is the table in the SQL server database. The oldest backup (table) is removed after filling up the defined number of backups (tables). See the MS SQL server and MS SQL Express description.
Database Access backups (obsolete) - Saving in the backup mode into the Access database. The backup is the table in the database (i.e. the *.mdb file). The oldest backup (table) is removed after filling up the defined number of backups (tables). The format of the *.MDB file is Access 2000.
This storage type has a limitation: If there are multiple PmaTrendGroup objects used with this storage type in the application, then there can be 63 such objects in one application at the most.

History:
Pm9.00.03: New type of saving into the PostgreSQL database.
PROMOTIC 9.0.31 SCADA system documentation MICROSYS, spol. s r.o.

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