From 1ad36eb0ef293a7a6ec70c7a6783e0096b96ea4e Mon Sep 17 00:00:00 2001
From: Zhou Kunqin <25057648+time-and-fate@users.noreply.github.com>
Date: Thu, 11 Jan 2024 19:28:54 +0800
Subject: [PATCH] statistics: fix missing nil check for mv index (#50313)

close pingcap/tidb#50298
---
 pkg/statistics/table.go                                |  2 +-
 .../r/planner/core/indexmerge_path.result              | 10 ++++++++++
 .../t/planner/core/indexmerge_path.test                |  8 ++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/pkg/statistics/table.go b/pkg/statistics/table.go
index e556b4f234..e488dfff04 100644
--- a/pkg/statistics/table.go
+++ b/pkg/statistics/table.go
@@ -448,7 +448,7 @@ func (coll *HistColl) GetAnalyzeRowCount() float64 {
 func (coll *HistColl) GetScaledRealtimeAndModifyCnt(idxStats *Index) (realtimeCnt, modifyCnt int64) {
 	// In theory, we can apply this scale logic on all indexes. But currently, we only apply it on the mv index to avoid
 	// any unexpected changes caused by factors like precision difference.
-	if idxStats.Info == nil || !idxStats.Info.MVIndex || !idxStats.IsFullLoad() {
+	if idxStats == nil || idxStats.Info == nil || !idxStats.Info.MVIndex || !idxStats.IsFullLoad() {
 		return coll.RealtimeCount, coll.ModifyCount
 	}
 	analyzeRowCount := coll.GetAnalyzeRowCount()
diff --git a/tests/integrationtest/r/planner/core/indexmerge_path.result b/tests/integrationtest/r/planner/core/indexmerge_path.result
index 6bfa6c0d93..09d8780510 100644
--- a/tests/integrationtest/r/planner/core/indexmerge_path.result
+++ b/tests/integrationtest/r/planner/core/indexmerge_path.result
@@ -704,3 +704,13 @@ select * from t ignore index (mvi) where json_contains(j, '[]');
 j
 []
 ["abc"]
+drop table if exists t;
+create table t(a int, b json);
+insert into t value (1, '{"a":[1,2,3], "b": [2,3,4]}');
+analyze table t;
+alter table t add index ibb( (cast(b->'$.b' as signed array)) );
+explain select /*+ use_index_merge(t) */ * from t where 10 member of (b->'$.b');
+id	estRows	task	access object	operator info
+IndexMerge_7	1.00	root		type: union
+├─IndexRangeScan_5(Build)	1.00	cop[tikv]	table:t, index:ibb(cast(json_extract(`b`, _utf8mb4'$.b') as signed array))	range:[10,10], keep order:false, stats:partial[ibb:missing, b:unInitialized]
+└─TableRowIDScan_6(Probe)	1.00	cop[tikv]	table:t	keep order:false, stats:partial[ibb:missing, b:unInitialized]
diff --git a/tests/integrationtest/t/planner/core/indexmerge_path.test b/tests/integrationtest/t/planner/core/indexmerge_path.test
index 96e92db1fd..07eaab9935 100644
--- a/tests/integrationtest/t/planner/core/indexmerge_path.test
+++ b/tests/integrationtest/t/planner/core/indexmerge_path.test
@@ -245,3 +245,11 @@ insert into t values ('[]');
 insert into t values ('["abc"]');
 select * from t use index (mvi) where json_contains(j, '[]');
 select * from t ignore index (mvi) where json_contains(j, '[]');
+
+# TestIssue50298
+drop table if exists t;
+create table t(a int, b json);
+insert into t value (1, '{"a":[1,2,3], "b": [2,3,4]}');
+analyze table t;
+alter table t add index ibb( (cast(b->'$.b' as signed array)) );
+explain select /*+ use_index_merge(t) */ * from t where 10 member of (b->'$.b');