Operators without upstream operators, such as DFEPipelineScan, SolutionInjections, and a DFESubquery with no static value injected, would have zero value. Units Out – The number of solutions produced as output of this operator. DFEDrain is a special case, where the number of solutions being ...
keysetname = "Group Keys"; } ExplainOpenGroup("Grouping Set", NULL, true, es); if (sortnode) { show_sort_group_keys(planstate, "Sort Key", sortnode->numCols, sortnode->sortColIdx, sortnode->sortOperators, sortnode->collations, sortnode->nullsFirst, ancestors, es); if (es->form...
The logical optimized abstract syntax tree (AST) for the DFE query plan is printed with information about the operator types that were considered while planning and the associated best- and worst-case costs to run the operators. The AST consists of the following type of nodes at the moment: ...
(4000), search_columns INT, id INT, parent_id INT, depth INT, position INT,is_last_child INT, cost INT, cardinality INT, bytes INT, rowset INT, other_tag VARCHAR(4000), partition_start VARCHAR(4000), partition_stop VARCHAR(4000), partition_id INT, other VARCHAR(4000), distribution ...
In the returned execution plan, for all probe-side child nodes of IndexJoin and Apply operators, the meaning of estRows since v6.4.0 is different from that before v6.4.0. You can find details in TiDB Query Execution Plan Overview. Currently, EXPLAIN in TiDB outputs 5 columns: id, estRow...
For example, J3_1_2_Stg1 indicates that the task with the ID of 3 depends on the M1 and M2 tasks. Dependencies between all operators in a task The operator string describes the execution semantics of a task. Operator string structure: In Task M2: Data source: mf_mc_bj.sale_detail...
RxJS provides a set of powerful aggregate operators that allow you to perform various types of aggregations on the values emitted by observables. Here's an overview of some key RxJS aggregate operators, including count, reduce, max, min, scan, and toArray....
For example, if a hash aggregate operator is used in the first step of a query plan, full data of downstream operators is required to create a hash table for an aggregate operation. For common queries with filter conditions, data is calculated and returned in real time. In this scenario, ...
1 row in set (0.00 sec) 一.OptimizingQueries with EXPLAIN The EXPLAINstatement can be used either as a way to obtain information about how MySQLexecutes a statement, or as a synonym for DESCRIBE: (1)When youprecede a SELECT statement with the keyword EXPLAIN, MySQL displays informationfrom ...
Range can beused when a key column is compared to a constant using any of the =, <>, >, >=, <, <=, IS NULL, <=>, BETWEEN, or IN() operators: index 这种连接类型和all一样,除了扫描索引树。发生在下面两种情况: 1、如果对于查询索引是一个覆盖索引并且可以满足这个表所有数据的查询,只是...