Query Plan Cache
A database runtime structure that retains previously compiled or optimized execution plans for reuse.
A plan cache reduces repeated compilation and optimization work, but reuse does not imply that one plan is optimal for every bind value or data distribution. For predicates whose selectivity changes sharply, the conditions under which a plan is reused matter as much as how it was first produced.
In Oracle workloads this connects directly to Bind Peeking, Adaptive Cursor Sharing, and Plan Regression.