CMP.10:4.6 - Return a usable representation and reopen it locally

Return the structure, its meaningful state, read and update procedures, and the resource consequence that motivated the change. A small worked operation should expose the invariant and a consequential change should test its maintenance.

Reconsider the choice when the query mix, update pattern, output identity, data magnitude or physical access cost changes. Preserve the abstract object and valid algorithms where they remain applicable. A newly required distinction that the old representation discarded may require returning to the source data, not merely rebuilding an index from the insufficient summary.