If [Display query plan] is selected in the Query Editor's options, [Display query plan ] becomes activated in the Query Editor toolbar.
You can check how the selected query will be executed, even without executing it, by clicking [Display query plan ] from the toolbar or by clicking <Ctrl+L>. You can also check query execution plan that have already been executed.
Since query plans are displayed all the time at the bottom of the Query Editor window, you can check the existing query plans by opening query plan history files without connecting to the database.
The query plan function retrieves the SQL execution plans it is used not for a one-time purpose but for a collection purpose to continuously manage and retrieve them. Every time you retrieve a query plan, the query plan history is accumulated. You can save this accumulated data to an .xml file. When you open the saved .xml file, you can check the original query plan and executed SQL statements. If it is a one-time retrieval, select [Disable to collecting histories ] to view the current query plan without recording history.
The [Query Explain] tab consists of a toolbar, query plan display pane, original statement display pane and query plan history pane.
If you select a query and then click [Display query plan ], the query plan is displayed in the [Query Explain] tab. The [Query Explain] tab shows the query plan summarized in the tree structure.
The [Query Explain] tab is located to the right of the [Result] tab. You can switch to the [Query Explain] tab while viewing the query result.
The Query Explain toolbar has the following functions:
In the query plan display pane, the query plan executed in each step is displayed in the tree structure.
Each item in the vertical axis is called a node. Each node contains different data. You can view the tree moving from the top to the bottom.
The horizontal axis is called an item and contains Type, Table, Index, Terms, CPU I/O cost, Disk I/O cost, and Total (ROW/PAGE).
The original statements of the query plan selected in the query plan pane are displayed below the query plan display pane.
Histories are displayed accumulatively in the query plan history pane every time a query plan is executed. # is the accumulation order and corresponds to the tab number below the query plan display pane. Date indicates the date when a query plan is executed, and Cost is the sum of CPU and Disk I/O costs. If you double-click an item in the query plan history pane, you can view the query plan again in the query plan display pane.
By using the query plan function, you can analyze data while viewing the query plan and the schema info of the corresponding table.
If you right-click a row where a table is located in the query plan display pane and then select [Show Schema Info], you can open and view the schema information of the table as well.
You can also view the information in a separate window by dragging the Schema Info pane out of the CUBRID Manager. This can be useful in an environment using multiple monitors.