Hello,
Does Phoenix provide hash aggregation? If not, is it on the roadmap, or
should I file a ticket? We have aggregation queries that do not require
sorted results.
For example, this EXPLAIN plan shows a CLIENT SORT.
*CREATE TABLE unsalted ( keyA BIGINT NOT NULL, keyB BIGINT NOT
NULL, val SMALLINT, CONSTRAINT pk PRIMARY KEY (keyA, keyB));*
*EXPLAINSELECT /*+ USE_SORT_MERGE_JOIN */ t1.val v1, t2.val v2, COUNT(*) c
FROM unsalted t1 JOIN unsalted t2 ON (t1.keyA = t2.keyA) GROUP BY t1.val,
t2.val;+------------------------------------------------------------+-----------------+----------------+--+|
PLAN | EST_BYTES_READ | EST_ROWS_READ |
|+------------------------------------------------------------+-----------------+----------------+--+|
SORT-MERGE-JOIN (INNER) TABLES | null | null |
|| CLIENT 1-CHUNK PARALLEL 1-WAY FULL SCAN OVER UNSALTED | null | null
| || AND | null |
null | || CLIENT 1-CHUNK PARALLEL 1-WAY FULL SCAN OVER UNSALTED | null
| null | || CLIENT SORTED BY [TO_DECIMAL(T1.VAL), T2.VAL] |
null | null | || CLIENT AGGREGATE INTO DISTINCT ROWS BY [T1.VAL, T2.VAL]
| null | null |
|+------------------------------------------------------------+-----------------+----------------+--+*
Thanks,
Gerald
