PyCharm 2023.3 Help

Query execution plan

The EXPLAIN command shows the execution plan of a statement. It means you can see details on the approach that the planner took to execute the statement. For example, how the tables are scanned, what join algorithms are used to bring together the required rows, statement execution costs, and other information.

Execution cost is the planner's guess at how long it takes to run the statement. The measurement is made in relative cost units. The execution cost has two options: start-up and total. The start-up cost shows how long it takes before the first row can be processed, while the total cost shows how long it takes to process all the rows.

PyCharm supports two types of execution plans:

  • Explain Plan: the result is shown in a mixed tree and table format on a dedicated Plan tab.

  • Explain Plan (Raw): the result is shown in a table format.

If you use the ANALYZE option with EXPLAIN, the statement is actually executed, not only planned. In this case, you can see the run time statistics in milliseconds.

Visualize a query plan

  1. Right-click an SQL statement, and select Explain Plan | Explain Plan.

  2. By default, you see the tree representation of the query in the Plan tab of the Services tool window. To visualize the query execution plan, click the Show Diagram button (the Show Visualization icon), or press Control+Alt+Shift+U.

Generate a flame graph for EXPLAIN

  1. Right-click an SQL statement, and select Explain Plan | Explain Plan.

  2. By default, you see the tree representation of the query in the Plan tab of the Services tool window. Click the Flame Graph button (the Flame Graph icon) and select between the following options:

    • Total Cost: how long it takes to return all the rows

    • Startup Cost: how long it takes before the first row can be processed.

Generate a flame graph for EXPLAIN ANALYSE

  1. Right-click an SQL statement, and select Explain Plan | Explain Analyse.

  2. By default, you see the tree representation of the query in the Plan tab of the Services tool window. Click the Flame Graph button (the Flame Graph icon) and select between the following options:

    • Total Cost: how long it takes to return all the rows (in relative cost units).

    • Actual Total Time: how long it takes to return all the rows (in milliseconds).

    • Startup Cost: how long it takes before the first row can be processed (in relative cost units).

    • Actual Startup Time: how long it takes before the first row can be processed (in milliseconds).

Last modified: 12 October 2023