5.9.9 Data compression

Its operation depends on the value of the CREATE_PP_TABLE_AFTER parameter in the CONFIG_INI.pm file. For the tables used during data loading and available storage options see the "Measurement result storage options" section.

1. It is set and the value of the USE_PARTITONS parameter is at least 2: if the DROP_DATA_AFTER parameter is set too then it drops the PVSR_MON_RES_A_... tables after they have been created more than DROP_DATA_AFTER days. If the DROP_DATA_AFTER is not set then it does not do any operation

2. In other cases: the data compression module runs once a day. Its operation depends for each measurement on the retain-raw-data of the measurement and on the value of the DELETE_DAILY_DATA_AFTER parameter:

·       If the DELETE_DAILY_DATA_AFTER parameter isn’t defined then it calculates an hourly average after the specified time for the measurement and deletes the raw data

·       If the DELETE_DAILY_DATA_AFTER parameter is less than the value specified for the measurement then it doesn’t calculate an hourly average but deletes the raw value from the database after the specified time for the measurement

·       If the DELETE_DAILY_DATA_AFTER parameter is greater than the value specified for the measurement then it calculates an hourly average after the specified time for the measurement, deletes the raw data and deletes the hourly data older than DELETE_DAILY_DATA_AFTER days