planner: correctly set StatsVersion of tablePlan in copTask

cmd/explaintest/r/explain_easy_stats.result

@@ -111,7 +111,7 @@ Projection	1999.00	root		eq(test.t1.c2, test.t2.c2)->Column#11
       └─IndexLookUp	1.00	root		
         ├─Limit(Build)	1.00	cop[tikv]		offset:0, count:1
         │ └─IndexRangeScan	1.25	cop[tikv]	table:t2, index:c1(c1)	range: decided by [eq(test.t1.c1, test.t2.c1)], keep order:true
-        └─TableRowIDScan(Probe)	1.00	cop[tikv]	table:t2	keep order:false, stats:pseudo
+        └─TableRowIDScan(Probe)	1.00	cop[tikv]	table:t2	keep order:false
 explain format = 'brief' select * from t1 order by c1 desc limit 1;
 id	estRows	task	access object	operator info
 Limit	1.00	root		offset:0, count:1

planner/core/exhaust_physical_plans.go

@@ -1071,6 +1071,10 @@ func (p *LogicalJoin) constructInnerIndexScanTask(
 				}
 			}
 		}
+		// We set `StatsVersion` here and fill other fields in `(*copTask).finishIndexPlan`. Since `copTask.indexPlan` may
+		// change before calling `(*copTask).finishIndexPlan`, we don't know the stats information of `ts` currently and on
+		// the other hand, it may be hard to identify `StatsVersion` of `ts` in `(*copTask).finishIndexPlan`.
+		ts.stats = &property.StatsInfo{StatsVersion: ds.tableStats.StatsVersion}
 		// If inner cop task need keep order, the extraHandleCol should be set.
 		if cop.keepOrder && !ds.tableInfo.IsCommonHandle {
 			var needExtraProj bool

planner/core/find_best_task.go

@@ -1194,6 +1194,10 @@ func (ds *DataSource) convertToIndexScan(prop *property.PhysicalProperty, candid
 		}.Init(ds.ctx, is.blockOffset)
 		ts.SetSchema(ds.schema.Clone())
 		ts.SetCost(cost)
+		// We set `StatsVersion` here and fill other fields in `(*copTask).finishIndexPlan`. Since `copTask.indexPlan` may
+		// change before calling `(*copTask).finishIndexPlan`, we don't know the stats information of `ts` currently and on
+		// the other hand, it may be hard to identify `StatsVersion` of `ts` in `(*copTask).finishIndexPlan`.
+		ts.stats = &property.StatsInfo{StatsVersion: ds.tableStats.StatsVersion}
 		cop.tablePlan = ts
 	}
 	cop.cst = cost

planner/core/integration_test.go

@@ -34,6 +34,7 @@ import (
 	"github.com/pingcap/tidb/session"
 	"github.com/pingcap/tidb/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/sessionctx/variable"
+	"github.com/pingcap/tidb/statistics/handle"
 	"github.com/pingcap/tidb/table"
 	"github.com/pingcap/tidb/util/collate"
 	"github.com/pingcap/tidb/util/testkit"
@@ -4217,6 +4218,31 @@ func (s *testIntegrationSuite) TestOutputSkylinePruningInfo(c *C) {
 	}
 }
 
+func (s *testIntegrationSuite) TestIssue27083(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("create table t(a int primary key, b int, c int, index idx_b(b))")
+	tk.MustExec("insert into t values (1,2,3), (4,5,6), (7,8,9), (10, 11, 12), (13,14,15), (16, 17, 18)")
+	do, _ := session.GetDomain(s.store)
+	c.Assert(do.StatsHandle().DumpStatsDeltaToKV(handle.DumpAll), IsNil)
+	tk.MustExec("analyze table t")
+
+	var input []string
+	var output []struct {
+		SQL  string
+		Plan []string
+	}
+	s.testData.GetTestCases(c, &input, &output)
+	for i, tt := range input {
+		s.testData.OnRecord(func() {
+			output[i].SQL = tt
+			output[i].Plan = s.testData.ConvertRowsToStrings(tk.MustQuery("explain format = 'brief' " + tt).Rows())
+		})
+		tk.MustQuery("explain format = 'brief' " + tt).Check(testkit.Rows(output[i].Plan...))
+	}
+}
+
 func (s *testIntegrationSuite) TestIssues27130(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")

planner/core/task.go

@@ -157,7 +157,12 @@ func (t *copTask) finishIndexPlan() {
 	var tableInfo *model.TableInfo
 	if t.tablePlan != nil {
 		ts := t.tablePlan.(*PhysicalTableScan)
+		originStats := ts.stats
 		ts.stats = t.indexPlan.statsInfo()
+		if originStats != nil {
+			// keep the original stats version
+			ts.stats.StatsVersion = originStats.StatsVersion
+		}
 		tableInfo = ts.Table
 	}
 	// Network cost of transferring rows of index scan to TiDB.
@@ -1170,7 +1175,12 @@ func (p *PhysicalLimit) sinkIntoIndexLookUp(t task) bool {
 		Offset: p.Offset,
 		Count:  p.Count,
 	}
+	originStats := ts.stats
 	ts.stats = p.stats
+	if originStats != nil {
+		// keep the original stats version
+		ts.stats.StatsVersion = originStats.StatsVersion
+	}
 	reader.stats = p.stats
 	if isProj {
 		proj.stats = p.stats

planner/core/testdata/integration_suite_in.json

@@ -349,5 +349,11 @@
       "select * from t where g = 5 order by f",
       "select * from t where d = 3 order by c, e"
     ]
+  },
+  {
+    "name": "TestIssue27083",
+    "cases": [
+      "select * from t use index (idx_b) where b = 2 limit 1"
+    ]
   }
 ]

planner/core/testdata/integration_suite_out.json

@@ -8,7 +8,7 @@
           "IndexLookUp 1.00 root  limit embedded(offset:2, count:1)",
           "├─Limit(Build) 3.00 cop[tikv]  offset:0, count:3",
           "│ └─IndexRangeScan 3.00 cop[tikv] table:tbl, index:idx_b_c(b, c) range:(1,+inf], keep order:false",
-          "└─TableRowIDScan(Probe) 1.00 cop[tikv] table:tbl keep order:false, stats:pseudo"
+          "└─TableRowIDScan(Probe) 1.00 cop[tikv] table:tbl keep order:false"
         ]
       },
       {
@@ -19,7 +19,7 @@
           "  └─IndexLookUp 3.00 root  ",
           "    ├─Limit(Build) 3.00 cop[tikv]  offset:0, count:3",
           "    │ └─IndexRangeScan 3.00 cop[tikv] table:tbl, index:idx_b_c(b, c) range:(1,+inf], keep order:true, desc",
-          "    └─TableRowIDScan(Probe) 3.00 cop[tikv] table:tbl keep order:false, stats:pseudo"
+          "    └─TableRowIDScan(Probe) 3.00 cop[tikv] table:tbl keep order:false"
         ]
       },
       {
@@ -29,7 +29,7 @@
           "├─Limit(Build) 3.00 cop[tikv]  offset:0, count:3",
           "│ └─Selection 3.00 cop[tikv]  gt(test.tbl.c, 1)",
           "│   └─IndexRangeScan 3.75 cop[tikv] table:tbl, index:idx_b_c(b, c) range:(1,+inf], keep order:false",
-          "└─TableRowIDScan(Probe) 1.00 cop[tikv] table:tbl keep order:false, stats:pseudo"
+          "└─TableRowIDScan(Probe) 1.00 cop[tikv] table:tbl keep order:false"
         ]
       },
       {
@@ -1883,5 +1883,19 @@
         ]
       }
     ]
+  },
+  {
+    "Name": "TestIssue27083",
+    "Cases": [
+      {
+        "SQL": "select * from t use index (idx_b) where b = 2 limit 1",
+        "Plan": [
+          "IndexLookUp 1.00 root  limit embedded(offset:0, count:1)",
+          "├─Limit(Build) 1.00 cop[tikv]  offset:0, count:1",
+          "│ └─IndexRangeScan 1.00 cop[tikv] table:t, index:idx_b(b) range:[2,2], keep order:false",
+          "└─TableRowIDScan(Probe) 1.00 cop[tikv] table:t keep order:false"
+        ]
+      }
+    ]
   }
 ]