<derivedN>:ID值n的行的派生表结果,派生表可能是从FROM子句中的一个子查询生成的(The row refers to the derived table result for the row with an id value of N. A derived table may result, for example, from a subquery in the FROM clause.)。 <subqueryN>:ID值n的行的物化子查询结果。 4....
filtered- The amount of rows unfiltered by the conditions in the WHERE clause. These rows will be joined to the table in the next row of the EXPLAIN plan. As mentioned previously, this is a guesstimate as well, so MySQL can be wrong with this estimation. ...
In the example in Figure27 below the where clause predicate is on the TIME table, which joins to the SALES table on the partition key TIME_ID. Partition pruning will happen at execution time after the WHERE clause predicate has been applied to the TIME table and the appropriate TIME_IDs ...
Query plans always begin with this static injection. If static solutions to inject can be derived from the query itself by combining various sources of static bindings (for example, fromVALUESorBINDclauses), then theSolutionInjectionoperator injects these derived static solutions. In the simplest ca...
unionM,N: The row refers to the union of the rows with id values of M and N. derivedN: The row refers to the derived table result for the row with an id value of N. A derived table may result, for example, from a subquery in the FROM clause. ...
<derivedN>: 这行指出派生表结果集在这行中的id值为N。A derived table may result, for example, from a subqueryin the FROM clause. <subqueryN>: 该行指的是物化查询在这行的ID值为N。 SeeSection 9.2.1.18.2,“Optimizing Subqueries with Subquery Materialization”. ...
static void show_tablesample(TableSampleClause *tsc, PlanState *planstate, List *ancestors, ExplainState *es);static void show_sort_info(SortState *sortstate, ExplainState *es);static void show_hash_info(HashState *hashstate, ExplainState *es);static void show_tidbitmap_info(BitmapHeapScan...
For example: Start with ID = 0 and given STATEMENT_ID. Use the CONNECT BY clause to walk the tree from parent to child, the join keys being STATEMENT_ID = PRIOR STATEMENT_ID and PARENT_ID = PRIOR ID. Use the pseudo-column LEVEL (associated with CONNECT BY) to indent the children. ...
JOIN, COUNT DISTINCT (a JOIN method), and GROUP BY clauses: If no distribution key is configured for the table or the distribution key setting is invalid, data is shuffled among multiple shards during the query. If redistribution occurs when you join multiple tables, the local join feature ...
Sequential ScanscanAmazon Redshift relation scan or table scan operator or step. Scans whole table sequentially from beginning to end; also evaluates query constraints for every row (Filter) if specified with WHERE clause. Also used to run INSERT, UPDATE, and DELETE statements. ...