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
DFEApply – Executes the function specified by functor in the arguments section, on the value stored in the specified variable DFEAlgoWriteProperty – Explain operator for the property-writing portion of mutate algorithm invocations. DFEBFSAlgo – Explain operator for invocations of the Breadth First...
A default PLAN_TABLE exists for every user without the need to create it beforehand. Using the DBMS_XPLAN.DISPLAY_CURSOR Function Alternatively the execution plan for an executed SQL statement can be generated and displayed by using the DBMS_XPLAN.DISPLAY_CURSOR function. The following example ...
MySQL was ableto do a LEFT JOIN optimization on the query and does not examine more rows inthis table for the previous row combination after it finds one row that matchesthe LEFT JOIN criteria. Here is an example of the type of query that can beoptimized this way: SELECT * FROM t1 LEF...
8062 User defined function (UDF) time limit. 8064 Optimizer limitations.Error CodesPossible error codes returned from the Visual Explain consolidator are:Error CodeDescription 0 Successful. 71 Invalid date format. 72 Invalid date separator. 73 Invalid time format. 74 Invalid time separator. 75 Invali...
In a non-restrictive database, EXECUTE privilege is granted to PUBLIC when the function is automatically created. Information returned The data type of the result is CLOB(50M). Example SELECT EXPLAIN_FORMAT_STATS(SNAPSHOT) FROM EXPLAIN_STATEMENT WHERE EXPLAIN_REQUESTER = 'DB2USER1' AND EXPLAIN_...
Keys such as the join key or group by key that are involved in expressions: If you use a CAST function to convert data types, the local join feature is not used. In this case, redistribution occurs. Examples: Example 1: Join two tables. The distribution key is invalid and redistribution...
When the rows to be read can be read during the optimization phase (for example, by reading index rows), there is no need to read any tables during query execution. The first condition is fulfilled when the query is implicitly grouped (contains an aggregate function but no GROUP BY ...
(APITest.test_cache_miss_explanations_new_function_in_loop) because: never seen function: <lambda> id=5036820896 defined at /Users/necula/Source/jax/tests/api_test.py:4549 but seen another function defined on the same line; maybe the function is being re-defined repeatedly, preventing caching...
Here is an example of the type of query that can be optimized this way: SELECT * FROM t1 LEFT JOIN t2 ON t1.id=t2.id WHERE t2.id IS NULL; Assume that t2.id is defined as NOT NULL. In this case, MySQL scans t1 and looks up the rows in t2 using the values of t1.id. ...