Optimizer Choices

Selectivity Is a Pinned Input

A selectivity estimate is a visible model input.

highlighted = computed this step

Selectivity is a pinned input

A selectivity estimate says what share of rows the filter keeps.

selectivity is explicit\text{selectivity is explicit}

Read the fraction

The pinned selectivity is 1/4.

selectivity shown\text{selectivity shown}

Optimizer-choice examples are named toy estimate-model outputs; they are not benchmark results, database-product claims, hardware claims, or real speed predictions.

Selectivity is a pinned input: table statstablerolerowCountdistinctKeysOrdersleft_after_filter_input126Customersright_join_input88 filter estimatelabelinputRowsselectivityestimatedRowsstatus filter121/43 plan estimate rowsplanformulaleft/buildright/probeestimatedWorkchosennested_loop_joinfiltered_left_rows * right_rows3824nohash_joinbuild_rows + probe_rows8311yes estimate factsfactvaluemodelNametoy_optimizer_estimate_v1leftRows12rightRows8selectivity1/4filteredRows3nestedLoopWork24hashJoinWork11chosenPlanhash_joinrealSpeedClaimnoproductClaimnorequiresBenchmarkForSpeedyes

No hidden decimal

The engine uses numerator and denominator integers, with no floating-point value.

integer fraction\text{integer fraction}

Summary

Changing the selectivity changes the estimate, so it stays visible.

estimate input\text{estimate input}