Postfix for the improved selectivity estimations, thanks to Denis Simonov

dyemanov · dyemanov · commit 12d807431f9e · 2026-03-13T09:08:38.000+03:00
diff --git a/src/jrd/optimizer/Optimizer.cpp b/src/jrd/optimizer/Optimizer.cpp
@@ -1240,7 +1240,8 @@ double Optimizer::estimateSelectivity(const BooleanList& filters, double cardina
 		// If the table is small enough, the hardcoded selectivity factors are causing
 		// too small resulting selectivity. Adjust the initial value to protect from this case.
 		const auto minSelectivity = MAXIMUM_SELECTIVITY / cardinality;
-		selectivity *= minSelectivity / selectivities.front();
+		if (selectivities.front() < minSelectivity)
+			selectivity *= minSelectivity / selectivities.front();
 	}
 
 	// Apply exponential backoff

Original file line number	Diff line number	Diff line change
`@@ -1240,7 +1240,8 @@ double Optimizer::estimateSelectivity(const BooleanList& filters, double cardina`
`1240`	`1240`	`// If the table is small enough, the hardcoded selectivity factors are causing`
`1241`	`1241`	`// too small resulting selectivity. Adjust the initial value to protect from this case.`
`1242`	`1242`	`const auto minSelectivity = MAXIMUM_SELECTIVITY / cardinality;`
`1243`		`- selectivity *= minSelectivity / selectivities.front();`
	`1243`	`+ if (selectivities.front() < minSelectivity)`
	`1244`	`+ selectivity *= minSelectivity / selectivities.front();`
`1244`	`1245`	`}`
`1245`	`1246`
`1246`	`1247`	`// Apply exponential backoff`