A stored outline is a saved set of optimizer hints bound to a SQL text so that the optimizer reproduces the same execution plan every time. Outlines live in the OUTLN schema, are created with CREATE OUTLINE or captured automatically, and are activated through the USE_STORED_OUTLINES setting.

Migrations care because outlines are a form of plan pinning. Their presence tells you which statements were fragile enough to need it, and any plan stability the application depends on has to be re-created with the target's own mechanisms, such as Query Store plan forcing on Azure SQL or hint-based approaches on PostgreSQL.

The 12.1 Upgrade Guide lists stored outlines as deprecated with plan baselines as the replacement, and the 26ai guide says they were deprecated in Oracle Database 11g and that 26ai is the terminal release, instructing users to migrate to SQL plan baselines. The pages used do not state which 11g release began the deprecation, and no desupport release has been named, so neither field is set here.

Stored outlines, born before 11.2, pinned an execution plan to a SQL text. In Oracle, they were succeeded by SQL plan baselines.

They did not make the Azure crossing because PostgreSQL offers no plan store or plan-forcing feature, while Azure SQL Query Store can force only captured plans it still retains. Outlines cannot be imported, so each desired plan must be captured and re-established—a modestly bureaucratic afterlife.

It is survived by Azure Database for PostgreSQL Flexible Server, only by workaround through pg_hint_plan. It is also survived partly by Azure SQL Database, where Query Store can force retained plans or attach hints without changing application code.