Gather information about embedded SQL statements with the PRTSQLINF command

 

The Print SQL Information (PRTSQLINF) command returns information about the embedded SQL statements in a program, SQL package (the object normally used to store the access plan for a remote query), or service program. This information is then stored in a spooled file.

PRTSQLINF provides information about:

• The SQL statements being executed

• The type of access plan used during execution. This includes information about how the query will be implemented, the indexes used, the join order, whether a sort is done, whether a database scan is sued, and whether an index is created.

• A list of the command parameters used to precompile the source member for the object.

• The CREATE PROCEDURE and CREATE FUNCTION statement text used to create external procedures or User Defined Functions.

This output is similar to the information that you can get from debug messages. However, while query debug messages work at runtime, PRTSQLINF works retroactively. You can also see this information in the second level text of the query governor inquiry message CPA4259.

You can issue PRTSQLINF in a couple of ways. First, you can run the PRTSQLINF command against a saved access plan. This means execute or at least prepare the query (using SQL's PREPARE statement) before you use the command. It is best to execute the query because the index created as a result of PREPARE is relatively sparse and may well change after the first run. PRTSQLINF's requirement of a saved access plan means the command cannot be used with OPNQRYF.

You can also run PRTSQLINF against functions, stored procedures, triggers, SQL packages, and programs from iSeries™ Navigator. This function is called Explain SQL. To view PRTSQLINF information, right-click an object and select Explain SQL.

 

Parent topic:

Optimizing query performance using query optimization tools

 

Related information

Print SQL Information (PRTSQLINF) command