When you execute a query in QueryPad, diagnostic information is shown in the Information Pane. The diagnostic information provides details about the action taken by the Query Processor when you submitted your query.
Diagnostics information is shown in the Information Pane.
To make use of the diagnostics information, you need to understand how the Query Processor responds when you submit a query.
When an SQL query is submitted, the Query Processor runs through the following phases:
- Parse the query (see SQL Parsing and Verification). During this phase the Query Processor checks your query has the correct syntax. If the syntax is correct, the Query Processor proceeds to the verification phase.
- Verify the query (see SQL Parsing and Verification). During this phase, the Query Processor checks that your query has correct grammar. If the grammar is correct, the Query Processor proceeds to the join optimization phase.
- Join optimization (see SQL Join Optimization). During this phase, the Query Processor calculates an efficient way to access the tables that are referenced in your query. When it has determined an appropriate access plan, the Query Processor executes your query.
- Execute the query (see SQL Execution). The Query Processor executes your query and returns the appropriate result set. Depending on the settings you have in place in QueryPad, the results may be shown in the Information Pane. The Information Pane will also contain diagnostic data.
For more detailed information, please refer to the documentation for each phase using the links shown above.
Further Information