Generic plan usage turned out to be quite poor idea.

arssher · arssher · commit 9728fb202045 · 2018-03-20T11:00:56.000+03:00
diff --git a/src/backend/utils/cache/plancache.c b/src/backend/utils/cache/plancache.c
@@ -1150,8 +1150,7 @@ GetCachedPlan(CachedPlanSource *plansource, ParamListInfo boundParams,
 	qlist = RevalidateCachedQuery(plansource, queryEnv);
 
 	/* Decide whether to use a custom plan */
-	/* customplan = choose_custom_plan(plansource, boundParams); */
-	customplan = false;
+	customplan = choose_custom_plan(plansource, boundParams);
 
 	if (!customplan)
 	{

Original file line number	Diff line number	Diff line change
`@@ -1150,8 +1150,7 @@ GetCachedPlan(CachedPlanSource *plansource, ParamListInfo boundParams,`
`1150`	`1150`	`qlist = RevalidateCachedQuery(plansource, queryEnv);`
`1151`	`1151`
`1152`	`1152`	`/* Decide whether to use a custom plan */`
`1153`		`- /* customplan = choose_custom_plan(plansource, boundParams); */`
`1154`		`- customplan = false;`
	`1153`	`+ customplan = choose_custom_plan(plansource, boundParams);`
`1155`	`1154`
`1156`	`1155`	`if (!customplan)`
`1157`	`1156`	`{`