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linrrarity
ac6d282671
### Key Optimizations - Reworked exact percentile state into a simpler `values + PercentileLevels + inited_flag` layout. - Removed the old Counts-based exact percentile path and replaced it with a lightweight `PercentileLevels` metadata structure. - Reduced add-path overhead by directly appending values into a contiguous buffer and initializing `percentile levels` only once. - Optimized multi-quantile finalize(`percentile_array`) by sorting quantiles through permutation once, then reusing incremental `nth_element` selection. ### Performance before: ```text Doris> select percentile(FUniqID, 0.91) from hits_100m; +---------------------------+ | percentile(FUniqID, 0.91) | +---------------------------+ | 8.749975206154981e+18 | +---------------------------+ 1 row in set (6.149 sec) Doris> select percentile_array(FUniqID, [0.12, 0.23, 0.34, 0.45, 0.56]) from hits_100m; +------------------------------------------------------------------------------------------------+ | percentile_array(FUniqID, [0.12, 0.23, 0.34, 0.45, 0.56]) | +------------------------------------------------------------------------------------------------+ | [0, 5.097819197233503e+18, 5.68906185719365e+18, 6.281280528073601e+18, 6.869583632113269e+18] | +------------------------------------------------------------------------------------------------+ 1 row in set (28.984 sec) Doris> select percentile_array(FUniqID, [0.12, 0.23, 0.34, 0.45, 0.56, 0.67, 0.78, 0.89, 0.91]) from hits_100m; ERROR 1105 (HY000): errCode = 2, detailMessage = (127.0.0.1)[E-3113]string column length is too large: total_length=7200000149, element_number=0, rows=0 ``` now ```text Doris> select percentile(FUniqID, 0.91) from hits_100m; +---------------------------+ | percentile(FUniqID, 0.91) | +---------------------------+ | 8.749975206154981e+18 | +---------------------------+ 1 row in set (2.107 sec) Doris> select percentile_array(FUniqID, [0.12, 0.23, 0.34, 0.45, 0.56]) from hits_100m; +------------------------------------------------------------------------------------------------+ | percentile_array(FUniqID, [0.12, 0.23, 0.34, 0.45, 0.56]) | +------------------------------------------------------------------------------------------------+ | [0, 5.097819197233503e+18, 5.68906185719365e+18, 6.281280528073601e+18, 6.869583632113269e+18] | +------------------------------------------------------------------------------------------------+ 1 row in set (5.903 sec) Doris> select percentile_array(FUniqID, [0.12, 0.23, 0.34, 0.45, 0.56, 0.67, 0.78, 0.89, 0.91]) from hits_100m; +--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | percentile_array(FUniqID, [0.12, 0.23, 0.34, 0.45, 0.56, 0.67, 0.78, 0.89, 0.91]) | +--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | [0, 5.097819197233503e+18, 5.68906185719365e+18, 6.281280528073601e+18, 6.869583632113269e+18, 7.459044216605808e+18, 8.044902013692362e+18, 8.640523572825436e+18, 8.749975206154981e+18] | +--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (8.866 sec) ```