Log Service provides two modes for debugging data processing scripts: Quick Preview and Advanced Preview.
Quick Preview
Quick Preview provides a fast, free way to check the syntax of a data processing script and verify that the output meets your expectations. You can use custom test data or select specific logs from a LogStore for testing. For more information, see Quick Preview.
During a Quick Preview, Log Service cannot actually connect to the resources specified by resource functions (res_local, res_rds_mysql, res_log_LogStore_pull, and res_oss_file). If your data processing involves resource functions, you can enter test data in the Dimension Table tab to preview the results.
Advanced Preview
Advanced Preview simulates the complete data processing workflow by connecting to a LogStore to read and process live data. This preview mode requires read permissions, has slower response times, and incurs data processing fees.
We recommend that you first use Quick Preview to confirm that the output meets your expectations. Then, use Advanced Preview to verify your resource function configurations. For more information, see Advanced Preview.