diff --git a/executor/index_lookup_merge_join.go b/executor/index_lookup_merge_join.go
index fabc5a9b34..964dd39de0 100644
--- a/executor/index_lookup_merge_join.go
+++ b/executor/index_lookup_merge_join.go
@@ -189,6 +189,12 @@ func (e *IndexLookUpMergeJoin) startWorkers(ctx context.Context) {
 	// TODO: consider another session currency variable for index merge join.
 	// Because its parallelization is not complete.
 	concurrency := e.ctx.GetSessionVars().IndexLookupJoinConcurrency()
+	if e.runtimeStats != nil {
+		runtimeStats := &execdetails.RuntimeStatsWithConcurrencyInfo{}
+		runtimeStats.SetConcurrencyInfo(execdetails.NewConcurrencyInfo("Concurrency", concurrency))
+		e.ctx.GetSessionVars().StmtCtx.RuntimeStatsColl.RegisterStats(e.id, runtimeStats)
+	}
+
 	resultCh := make(chan *lookUpMergeJoinTask, concurrency)
 	e.resultCh = resultCh
 	e.joinChkResourceCh = make([]chan *chunk.Chunk, concurrency)
@@ -741,11 +747,5 @@ func (e *IndexLookUpMergeJoin) Close() error {
 	// cancelFunc control the outer worker and outer worker close the task channel.
 	e.workerWg.Wait()
 	e.memTracker = nil
-	if e.runtimeStats != nil {
-		concurrency := cap(e.resultCh)
-		runtimeStats := &execdetails.RuntimeStatsWithConcurrencyInfo{}
-		runtimeStats.SetConcurrencyInfo(execdetails.NewConcurrencyInfo("Concurrency", concurrency))
-		e.ctx.GetSessionVars().StmtCtx.RuntimeStatsColl.RegisterStats(e.id, runtimeStats)
-	}
 	return e.baseExecutor.Close()
 }
diff --git a/executor/join_test.go b/executor/join_test.go
index 3492b5a4a3..b8c38331bd 100644
--- a/executor/join_test.go
+++ b/executor/join_test.go
@@ -2321,6 +2321,11 @@ func (s *testSuiteJoinSerial) TestExplainAnalyzeJoin(c *C) {
 	c.Assert(len(rows), Equals, 7)
 	c.Assert(rows[0][0], Matches, "HashJoin.*")
 	c.Assert(rows[0][5], Matches, "time:.*, loops:.*, build_hash_table:{total:.*, fetch:.*, build:.*}, probe:{concurrency:5, total:.*, max:.*, probe:.*, fetch:.*}")
+	// Test for index merge join.
+	rows = tk.MustQuery("explain analyze select /*+ INL_MERGE_JOIN(t1, t2) */ * from t1,t2 where t1.a=t2.a;").Rows()
+	c.Assert(len(rows), Equals, 9)
+	c.Assert(rows[0][0], Matches, "IndexMergeJoin_.*")
+	c.Assert(rows[0][5], Matches, fmt.Sprintf(".*Concurrency:%v.*", tk.Se.GetSessionVars().IndexLookupJoinConcurrency()))
 }
 
 func (s *testSuiteJoinSerial) TestIssue20270(c *C) {