diff --git a/contrib/auto_explain/auto_explain.c b/contrib/auto_explain/auto_explain.c
index 56c549d84c1..dcff9cba48c 100644
--- a/contrib/auto_explain/auto_explain.c
+++ b/contrib/auto_explain/auto_explain.c
@@ -371,8 +371,15 @@ explain_ExecutorEnd(QueryDesc *queryDesc)
 {
 	if (queryDesc->totaltime && auto_explain_enabled())
 	{
+		MemoryContext oldcxt;
 		double		msec;
 
+		/*
+		 * Make sure we operate in the per-query context, so any cruft will be
+		 * discarded later during ExecutorEnd.
+		 */
+		oldcxt = MemoryContextSwitchTo(queryDesc->estate->es_query_cxt);
+
 		/*
 		 * Make sure stats accumulation is done.  (Note: it's okay if several
 		 * levels of hook all do this.)
@@ -424,9 +431,9 @@ explain_ExecutorEnd(QueryDesc *queryDesc)
 					(errmsg("duration: %.3f ms  plan:\n%s",
 							msec, es->str->data),
 					 errhidestmt(true)));
-
-			pfree(es->str->data);
 		}
+
+		MemoryContextSwitchTo(oldcxt);
 	}
 
 	if (prev_ExecutorEnd)