Bugfix. The predicted_cardinality field of a plan node could be

danolivo · danolivo · commit 8651c232c324 · 2021-06-28T13:33:17.000+03:00
established by previous execution of this plan in another query.
diff --git a/postprocessing.c b/postprocessing.c
@@ -279,11 +279,14 @@ learnOnPlanState(PlanState *p, void *context)
 			learn_rows = p->instrument->ntuples / p->instrument->nloops;
 	}
 
-	/* Calculate predicted cardinality */
-	if (p->plan->predicted_cardinality > 0.)
+	/*
+	 * Calculate predicted cardinality.
+	 * We could find a positive value of predicted cardinality in the case of
+	 * reusing plan caused by the rewriting procedure.
+	 * Also it may be caused by using of a generic plan.
+	 */
+	if (p->plan->predicted_cardinality > 0. && query_context.use_aqo)
 	{
-		Assert(query_context.use_aqo);
-
 		/* AQO made prediction. use it. */
 		predicted = p->plan->predicted_cardinality;
 	}

Original file line number	Diff line number	Diff line change
`@@ -279,11 +279,14 @@ learnOnPlanState(PlanState p, void context)`
`279`	`279`	`learn_rows = p->instrument->ntuples / p->instrument->nloops;`
`280`	`280`	`}`
`281`	`281`
`282`		`- /* Calculate predicted cardinality */`
`283`		`- if (p->plan->predicted_cardinality > 0.)`
	`282`	`+ /*`
	`283`	`+ * Calculate predicted cardinality.`
	`284`	`+ * We could find a positive value of predicted cardinality in the case of`
	`285`	`+ * reusing plan caused by the rewriting procedure.`
	`286`	`+ * Also it may be caused by using of a generic plan.`
	`287`	`+ */`
	`288`	`+ if (p->plan->predicted_cardinality > 0. && query_context.use_aqo)`
`284`	`289`	`{`
`285`		`- Assert(query_context.use_aqo);`
`286`		`-`
`287`	`290`	`/* AQO made prediction. use it. */`
`288`	`291`	`predicted = p->plan->predicted_cardinality;`
`289`	`292`	`}`