The FOREIGN KEY relationship plays the main part in this process as tables must be related to each other. Let us have a look at the scenario for MySQL EXPLAIN with example: we created external keys for a table w
suppressed options COST and BYTES The Note Section In addition to the plan and the predicate information, the DBMS_XPLAN package displays additional information in the NOTE section, such as when dynamic sampling was used during query optimization or that star transformation was applied to the query...
WhenEXPLAINis used with an explainable statement, MySQL displays information from the optimizer about the statement execution plan. That is, MySQL explains how it would process the statement, including information about how tables are joined and in which order. For information about usingEXPLAINto obt...
Both queries need only 10 values to calculate their results, but while the first query has to read all 1 billion rows of the entire table, the second query reads only 8192 rows (the default size of the table’sindex_granularity). We can see why this is by running the queries through ...
If SQL query performance is poor or query results do not meet expectations, you can execute the EXPLAIN and EXPLAIN ANALYZE statements in Hologres to obtain execution plans of query statements. This way, you can optimize query statements or database structures. This topic describes how to execute...
Oracle Database PL/SQL Packages and Types Reference for more information on the DBMS_XPLAN package 12.4.1 Customizing PLAN_TABLE Output If you have specified a statement identifier, then you can write your own script to query the PLAN_TABLE. For example: Start with ID = 0 and given STATEMEN...
A method for selectively preparing customized reports of query explain data comprises selectively retrieving from the database subsets of the query explain data for the at least one query statement; f
suppressed options COST and BYTES The Note Section In addition to the plan and the predicate information, the DBMS_XPLAN package displays additional information in the NOTE section, such as when dynamic sampling was used during query optimization or that star transformation was applied to the query...
suppressed options COST and BYTES The Note Section In addition to the plan and the predicate information, the DBMS_XPLAN package displays additional information in the NOTE section, such as when dynamic sampling was used during query optimization or that star transformation was applied to the qu...