EXPLAIN SELECT /*+ PARALLEL(8) */ count(*) 这个指定了并行度 8 dop还是1 MySQL [datax_test]> EXPLAIN SELECT /*+ PARALLEL(8) */ count(*) from test; | Query Plan | | ============================================================================================ |ID|OPERATOR |NAME |EST. ROWS|COST | |0 |SCALAR GROUP BY | |1 |22365570| |1 | PX COORDINATOR | |1 |15577735| |2 | EXCHANGE OUT DISTR |:EX10000 |1 |15577735| |3 | MERGE GROUP BY | |1 |15577735| |4 | PX PARTITION ITERATOR| |35536096 |8789900 | |5 | TABLE SCAN |test(idx_orderno_sku)|35536096 |8789900 | Outputs & filters: 0 - output([T_FUN_COUNT_SUM(T_FUN_COUNT(*))]), filter(nil), group(nil), agg_func([T_FUN_COUNT_SUM(T_FUN_COUNT(*))]) 1 - output([T_FUN_COUNT(*)]), filter(nil) 2 - output([T_FUN_COUNT(*)]), filter(nil), dop=1 3 - output([T_FUN_COUNT(*)]), filter(nil), group(nil), agg_func([T_FUN_COUNT(*)]) 4 - output([1]), filter(nil) 5 - output([1]), filter(nil), access([test.sub_order_no]), partitions(p[0-7])
mysql或者obclient登录的时候需要加上-c ,默认是--skip-comments
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