How do I delete pre-downsampling rules - Lindorm - Alibaba Cloud Documentation Center

You can use the DROP PREDOWNSAMPLE syntax to delete the pre-downsampling rules configured for a table.

Applicable engines and versions

The DROP PREDOWNSAMPLE syntax is applicable only to all versions of LindormTSDB.

Syntax

drop_predownsample_statement ::= DROP PREDOWNSAMPLE time_interval
                                    AGGREGATORS '('function_identifier ( ',' function_identifier) ')' ON table_identifier
time_interval                  ::= interval units

Parameters

Parameter	Description
interval	The interval at which time series data is aggregated. The value of this parameter is a positive integer.
units	The unit of the interval. Valid values: s (seconds), m (minutes), h (hours), and d (days).
AGGREGATORS	Aggregation functions supported in pre-downsampling. Valid values: count: returns the total number of data points. first: returns the first value. last: returns the last value. min: returns the minimum value. max: returns the maximum value. sum: returns the sum of the values. Note The avg function is not supported in pre-downsampling. You can calculate the average value of pre-downsampled data by using the results of the count and sum functions. However, if data is repeatedly added and overwritten, the average value may be inaccurate.
function_identifier	The name of the aggregation function. Note You can specify one or more aggregation functions with the same interval in a single statement. You can also specify multiple aggregation functions in multiple statements.
table_identifier	The name of the time series table.

Examples

DROP PREDOWNSAMPLE `1d` AGGREGATORS (`sum`, `max`) ON sensor;