| -> Limit: 100 row(s) (cost=14.62 rows=1) (actual time=1.252..1.252 rows=0 loops=1) -> Gather (merge sort; slice: 1; workers: 1; nodes: 2) (cost=14.62 rows=1) (actual time=1.250..1.250 rows=0 loops=1) -> Limit: 100 row(s) (cost=4.52 rows=1) (actual time=0.084,0....
-> Gather (merge sort; slice: 1; workers: 256; actual workers: 32) (cost=1408498.03 rows=256) -> Limit: 1 row(s) (cost=1408404.20 rows=1) -> Sort: <temporary>.value DESC, limit input to 1 row(s) per chunk (cost=1408404.20 rows=803182) -> Filter: (sum((partsupp.PS_SUPPLYCOS...
Example 3:Extract existing access path information to capture EXPLAIN records for the cached statement with statement ID 124. Assume that host variable SID contains 124. EXPLAIN STMTCACHE STMTID :SID; Example 4:Extract existing access path information to capture one row of EXPLAIN data for each ...
Example 1-4, "EXPLAIN PLAN Output"is an example of the plan table output when using theUTLXPLS.SQLscript. If you have specified a statement identifier, then you can write your own script to query thePLAN_TABLE. For example: Start with ID = 0 and givenSTATEMENT_ID. Use theCONNECTBYclau...
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 the optimizer about the query...
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. ...
select * from users where name = '张三' and email = 'zhangsan@example.com'; 2.字段: explain select users.* from users inner join orders on users.id = orders.id; 3.函数 explain select users.* from users inner join orders on users.id = trim(orders.id); ...
The following is a basic example of openCypher explain output. The query is a single-node lookup in the air routes dataset for a node with the airport code ATL that invokes explain using the details mode: ## sample query aws neptune-graph execute-query \ --region <region> \ --graph-...
Sort Sort is used to sort data in ascending order (ASC) or descending order (DESC), which is usually used with the ORDER BY clause. In this example, data in the l_shipdate column of the TPC-H lineitem table is sorted. EXPLAIN SELECT l_shipdate FROM public.lineitem ORDER BY l_...
For example, select_type is DELETE for DELETE statements. table (JSON name: table_name) The name of the table to which the row of output refers. This can also be one of the following values: <unionM,N>: The row refers to the union of the rows with id values of M and N. ...