planner: use a deep copy for accessPath when clone DataSource (#13620)

planner/core/integration_test.go

@@ -255,3 +255,27 @@ func (s *testIntegrationSuite) TestNoneAccessPathsFoundByIsolationRead(c *C) {
 	c.Assert(err, NotNil)
 	c.Assert(err.Error(), Equals, "[planner:1815]Internal : Can not find access path matching 'tidb_isolation_read_engines'(value: 'tiflash'). Available values are 'tikv'.")
 }
+
+func (s *testIntegrationSuite) TestPartitionTableStats(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, b int)partition by range columns(a)(partition p0 values less than (10), partition p1 values less than(20), partition p2 values less than(30));")
+	tk.MustExec("insert into t values(21, 1), (22, 2), (23, 3), (24, 4), (15, 5)")
+	tk.MustExec("analyze table t")
+
+	var input []string
+	var output []struct {
+		SQL    string
+		Result []string
+	}
+	s.testData.GetTestCases(c, &input, &output)
+	for i, tt := range input {
+		s.testData.OnRecord(func() {
+			output[i].SQL = tt
+			output[i].Result = s.testData.ConvertRowsToStrings(tk.MustQuery(tt).Rows())
+		})
+		tk.MustQuery(tt).Check(testkit.Rows(output[i].Result...))
+	}
+}

planner/core/rule_partition_processor.go

@@ -164,6 +164,11 @@ func (s *partitionProcessor) prune(ds *DataSource) (LogicalPlan, error) {
 		newDataSource.baseLogicalPlan = newBaseLogicalPlan(ds.SCtx(), plancodec.TypeTableScan, &newDataSource, ds.blockOffset)
 		newDataSource.isPartition = true
 		newDataSource.physicalTableID = pi.Definitions[i].ID
+		newDataSource.possibleAccessPaths = make([]*accessPath, len(ds.possibleAccessPaths))
+		for i := range ds.possibleAccessPaths {
+			newPath := *ds.possibleAccessPaths[i]
+			newDataSource.possibleAccessPaths[i] = &newPath
+		}
 		// There are many expression nodes in the plan tree use the original datasource
 		// id as FromID. So we set the id of the newDataSource with the original one to
 		// avoid traversing the whole plan tree to update the references.

planner/core/testdata/integration_suite_in.json

@@ -25,5 +25,14 @@
       // LeftOuterJoin should no be simplified to InnerJoin.
       "explain select * from t t1 left join t t2 on t1.a = t2.a where cast(t1.b as date) >= '2019-01-01'"
     ]
+  },
+  {
+    "name": "TestPartitionTableStats",
+    "cases": [
+      "explain select * from t order by a",
+      "select * from t order by a",
+      "explain select * from t order by a limit 3",
+      "select * from t order by a limit 3"
+    ]
   }
 ]

planner/core/testdata/integration_suite_out.json

@@ -77,5 +77,59 @@
         ]
       }
     ]
+  },
+  {
+    "Name": "TestPartitionTableStats",
+    "Cases": [
+      {
+        "SQL": "explain select * from t order by a",
+        "Result": [
+          "Sort_8 10005.00 root Column#1:asc",
+          "└─Union_11 10005.00 root ",
+          "  ├─TableReader_13 10000.00 root data:TableScan_12",
+          "  │ └─TableScan_12 10000.00 cop[tikv] table:t, partition:p0, range:[-inf,+inf], keep order:false, stats:pseudo",
+          "  ├─TableReader_15 1.00 root data:TableScan_14",
+          "  │ └─TableScan_14 1.00 cop[tikv] table:t, partition:p1, range:[-inf,+inf], keep order:false",
+          "  └─TableReader_17 4.00 root data:TableScan_16",
+          "    └─TableScan_16 4.00 cop[tikv] table:t, partition:p2, range:[-inf,+inf], keep order:false"
+        ]
+      },
+      {
+        "SQL": "select * from t order by a",
+        "Result": [
+          "15 5",
+          "21 1",
+          "22 2",
+          "23 3",
+          "24 4"
+        ]
+      },
+      {
+        "SQL": "explain select * from t order by a limit 3",
+        "Result": [
+          "TopN_16 3.00 root Column#1:asc, offset:0, count:3",
+          "└─Union_20 7.00 root ",
+          "  ├─TopN_21 3.00 root Column#1:asc, offset:0, count:3",
+          "  │ └─TableReader_29 3.00 root data:TopN_28",
+          "  │   └─TopN_28 3.00 cop[tikv] Column#1:asc, offset:0, count:3",
+          "  │     └─TableScan_27 10000.00 cop[tikv] table:t, partition:p0, range:[-inf,+inf], keep order:false, stats:pseudo",
+          "  ├─TopN_34 1.00 root Column#1:asc, offset:0, count:3",
+          "  │ └─TableReader_42 1.00 root data:TableScan_41",
+          "  │   └─TableScan_41 1.00 cop[tikv] table:t, partition:p1, range:[-inf,+inf], keep order:false",
+          "  └─TopN_43 3.00 root Column#1:asc, offset:0, count:3",
+          "    └─TableReader_51 3.00 root data:TopN_50",
+          "      └─TopN_50 3.00 cop[tikv] Column#1:asc, offset:0, count:3",
+          "        └─TableScan_49 4.00 cop[tikv] table:t, partition:p2, range:[-inf,+inf], keep order:false"
+        ]
+      },
+      {
+        "SQL": "select * from t order by a limit 3",
+        "Result": [
+          "15 5",
+          "21 1",
+          "22 2"
+        ]
+      }
+    ]
   }
 ]