the MySQL optimizer considers many techniques to efficiently performthe lookups involved in an SQL query. A query on a huge table can be performedwithout reading all the rows; a join involving several tables can be performedwithout comparing every combination of rows. The set of operations...
Some operators and functions that are not supported by HQE are executed by PQE. PQE is less efficient than HQE. If an execution plan contains the ExecuteExternalSQL operator, PQE is used. Example 1: An SQL statement uses PQE. CREATE TABLE pqe_test(a text); INSERT INTO pqe_test VALUES...
Formatting the execution plan The format parameter for the functions in the DBMS_XPLAN package is highly customizable and can display as little (high-level) or as much (low-level) details as required or desired in the plan output. There are three pre-defined formats available: BASIC The...
Before forwarding a packet, the firewall compares the IP header and TCP header against a user-defined table – rule base – which contains the rules that dictate whether the firewall should deny or permit packets to pass. The rules are scanned in sequential order until the packet filter finds...
The join type.For descriptions of the different types, see EXPLAIN Join Types. --对表所使用的访问方式。 2.1.5 possible_keys Thepossible_keys column indicates which indexes MySQL can choose from use to findthe rows in this table. Note that this column is totally independent of theorder of th...
You can also intuitively update each individual FIS rule base to check possible variations in output generation to further improve the performance of the support system. Helper Functions Get functionfis = constructFIS(name,numMFs,in1range,in2range,outrange,in1,in2,out)% Construct a Sugeno FIS....
The condition type is used for different functions. In pricing, for example, the condition type lets you differentiate between different kinds of discount; in output determination, between different output types such as order confirmation or delivery note; in batch determination, between different strat...
What does it mean when we say Azure uses Virtual Networking? How does software defined networking work? End of the scene, we interact with cloud through physical networking only. How is the boundary maintained in the cloud? Please provide some resources to understand the layout of virtual networ...
Sessions are isolated from users, and therefore users can only view the data of the current session and current user. PLAN_TABLE cannot be joined with GDS foreign tables. For a query that cannot be pushed down, only such information as REMOTE_QUERY and CTE can be collected from PLAN_TABLE...
Discuss how managerial accounting is useful for providing information for at least one of the following management functions: directing, controlling. Why might it be important to have internal documents produces as an output of the accounting information system? What ar...