Plan

A plan is the executable control structure DB2 loads when your program runs. Every DB2 program executes under a plan.

What is a plan

• A plan is created by BIND PLAN, either from DBRMs directly or from a list of packages (PKLIST).
• It is stored in the DB2 directory and named in the JCL (or DSN RUN) that executes the program.
• At run time DB2 loads the plan to find the access paths for the program's SQL.
• One plan can serve many programs, and one program always runs under exactly one plan per execution.

Plans with packages vs plans without

• Classic style: BIND PLAN with MEMBER and LIBRARY binds DBRMs straight into the plan. Any change means rebinding the whole plan.
• Modern style: BIND PLAN with PKLIST(collection.*). The plan only points to packages, so you rebind just one package when one program changes.
• Mixed style is allowed: a plan can list both packages and DBRMs together.
• For any application with more than a few programs, the package style is easier to maintain.

The PKLIST parameter

• PKLIST names collections and packages in search order, for example PKLIST(TESTCOLL.*, PRODCOLL.PAY01).
• A trailing .* means all packages in that collection.
• Order matters: DB2 uses the first match it finds, so put the preferred collection first.
• PKLIST is a BIND PLAN parameter. It does not exist on BIND PACKAGE.

Example: BIND PLAN with PKLIST

• The plan PAYPLAN points at every package in collection PAYROLLP. RETAIN keeps existing authorizations on replace:
  
  DSN SYSTEM(DB2A) BIND PLAN (PAYPLAN) PKLIST (PAYROLLP.*) ACTION (REPLACE) RETAIN ISOLATION (CS) END