This is an automated cherry-pick of pingcap#38358

Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>

executor/analyze_test.go

@@ -17,6 +17,10 @@ package executor_test
 import (
 	"context"
 	"fmt"
+<<<<<<< HEAD
+=======
+	"io/ioutil"
+>>>>>>> e8d265981a (statistics: support merge global topn in concurrency (#38358))
 	"strconv"
 	"strings"
 	"sync"
@@ -1159,3 +1163,78 @@ func (s *testSuite10) TestAdjustSampleRateNote(c *C) {
 	tk.MustExec("analyze table t")
 	tk.MustQuery("show warnings").Check(testkit.Rows("Note 1105 Analyze use auto adjusted sample rate 1.000000 for table test.t."))
 }
+
+func TestAnalyzePartitionTableByConcurrencyInDynamic(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("set @@tidb_partition_prune_mode='dynamic'")
+	tk.MustExec("use test")
+	tk.MustExec("create table t(id int) partition by hash(id) partitions 4")
+	testcases := []struct {
+		concurrency string
+	}{
+		{
+			concurrency: "1",
+		},
+		{
+			concurrency: "2",
+		},
+		{
+			concurrency: "3",
+		},
+		{
+			concurrency: "4",
+		},
+		{
+			concurrency: "5",
+		},
+	}
+	// assert empty table
+	for _, tc := range testcases {
+		concurrency := tc.concurrency
+		fmt.Println("testcase ", concurrency)
+		tk.MustExec(fmt.Sprintf("set @@tidb_merge_partition_stats_concurrency=%v", concurrency))
+		tk.MustQuery("select @@tidb_merge_partition_stats_concurrency").Check(testkit.Rows(concurrency))
+		tk.MustExec("analyze table t")
+		tk.MustQuery("show stats_topn where partition_name = 'global' and table_name = 't'")
+	}
+
+	for i := 1; i <= 500; i++ {
+		for j := 1; j <= 20; j++ {
+			tk.MustExec(fmt.Sprintf("insert into t (id) values (%v)", j))
+		}
+	}
+	var expected [][]interface{}
+	for i := 1; i <= 20; i++ {
+		expected = append(expected, []interface{}{
+			strconv.FormatInt(int64(i), 10), "500",
+		})
+	}
+	testcases = []struct {
+		concurrency string
+	}{
+		{
+			concurrency: "1",
+		},
+		{
+			concurrency: "2",
+		},
+		{
+			concurrency: "3",
+		},
+		{
+			concurrency: "4",
+		},
+		{
+			concurrency: "5",
+		},
+	}
+	for _, tc := range testcases {
+		concurrency := tc.concurrency
+		fmt.Println("testcase ", concurrency)
+		tk.MustExec(fmt.Sprintf("set @@tidb_merge_partition_stats_concurrency=%v", concurrency))
+		tk.MustQuery("select @@tidb_merge_partition_stats_concurrency").Check(testkit.Rows(concurrency))
+		tk.MustExec("analyze table t")
+		tk.MustQuery("show stats_topn where partition_name = 'global' and table_name = 't'").CheckAt([]int{5, 6}, expected)
+	}
+}

sessionctx/variable/session.go

@@ -955,6 +955,135 @@ type SessionVars struct {
 		curr int8
 		data [2]stmtctx.StatementContext
 	}
+<<<<<<< HEAD
+=======
+
+	// Rng stores the rand_seed1 and rand_seed2 for Rand() function
+	Rng *mathutil.MysqlRng
+
+	// EnablePaging indicates whether enable paging in coprocessor requests.
+	EnablePaging bool
+
+	// EnableLegacyInstanceScope says if SET SESSION can be used to set an instance
+	// scope variable. The default is TRUE.
+	EnableLegacyInstanceScope bool
+
+	// ReadConsistency indicates the read consistency requirement.
+	ReadConsistency ReadConsistencyLevel
+
+	// StatsLoadSyncWait indicates how long to wait for stats load before timeout.
+	StatsLoadSyncWait int64
+
+	// SysdateIsNow indicates whether Sysdate is an alias of Now function
+	SysdateIsNow bool
+	// EnableMutationChecker indicates whether to check data consistency for mutations
+	EnableMutationChecker bool
+	// AssertionLevel controls how strict the assertions on data mutations should be.
+	AssertionLevel AssertionLevel
+	// IgnorePreparedCacheCloseStmt controls if ignore the close-stmt command for prepared statement.
+	IgnorePreparedCacheCloseStmt bool
+	// EnableNewCostInterface is a internal switch to indicates whether to use the new cost calculation interface.
+	EnableNewCostInterface bool
+	// CostModelVersion is a internal switch to indicates the Cost Model Version.
+	CostModelVersion int
+	// BatchPendingTiFlashCount shows the threshold of pending TiFlash tables when batch adding.
+	BatchPendingTiFlashCount int
+	// RcWriteCheckTS indicates whether some special write statements don't get latest tso from PD at RC
+	RcWriteCheckTS bool
+	// RemoveOrderbyInSubquery indicates whether to remove ORDER BY in subquery.
+	RemoveOrderbyInSubquery bool
+	// NonTransactionalIgnoreError indicates whether to ignore error in non-transactional statements.
+	// When set to false, returns immediately when it meets the first error.
+	NonTransactionalIgnoreError bool
+
+	// MaxAllowedPacket indicates the maximum size of a packet for the MySQL protocol.
+	MaxAllowedPacket uint64
+
+	// TiFlash related optimization, only for MPP.
+	TiFlashFineGrainedShuffleStreamCount int64
+	TiFlashFineGrainedShuffleBatchSize   uint64
+
+	// RequestSourceType is the type of inner request.
+	RequestSourceType string
+
+	// MemoryDebugModeMinHeapInUse indicated the minimum heapInUse threshold that triggers the memoryDebugMode.
+	MemoryDebugModeMinHeapInUse int64
+	// MemoryDebugModeAlarmRatio indicated the allowable bias ratio of memory tracking accuracy check.
+	// When `(memory trakced by tidb) * (1+MemoryDebugModeAlarmRatio) < actual heapInUse`, an alarm log will be recorded.
+	MemoryDebugModeAlarmRatio int64
+
+	// EnableAnalyzeSnapshot indicates whether to read data on snapshot when collecting statistics.
+	// When it is false, ANALYZE reads the latest data.
+	// When it is true, ANALYZE reads data on the snapshot at the beginning of ANALYZE.
+	EnableAnalyzeSnapshot bool
+
+	// DefaultStrMatchSelectivity adjust the estimation strategy for string matching expressions that can't be estimated by building into range.
+	// when > 0: it's the selectivity for the expression.
+	// when = 0: try to use TopN to evaluate the like expression to estimate the selectivity.
+	DefaultStrMatchSelectivity float64
+
+	// TiFlashFastScan indicates whether use fast scan in TiFlash
+	TiFlashFastScan bool
+
+	// PrimaryKeyRequired indicates if sql_require_primary_key sysvar is set
+	PrimaryKeyRequired bool
+
+	// EnablePreparedPlanCache indicates whether to enable prepared plan cache.
+	EnablePreparedPlanCache bool
+
+	// GeneralPlanCacheSize controls the size of general plan cache.
+	PreparedPlanCacheSize uint64
+
+	// EnableGeneralPlanCache indicates whether to enable general plan cache.
+	EnableGeneralPlanCache bool
+
+	// GeneralPlanCacheSize controls the size of general plan cache.
+	GeneralPlanCacheSize uint64
+
+	// ConstraintCheckInPlacePessimistic controls whether to skip the locking of some keys in pessimistic transactions.
+	// Postpone the conflict check and constraint check to prewrite or later pessimistic locking requests.
+	ConstraintCheckInPlacePessimistic bool
+
+	// EnableTiFlashReadForWriteStmt indicates whether to enable TiFlash to read for write statements.
+	EnableTiFlashReadForWriteStmt bool
+
+	// EnableUnsafeSubstitute indicates whether to enable generate column takes unsafe substitute.
+	EnableUnsafeSubstitute bool
+
+	// ForeignKeyChecks indicates whether to enable foreign key constraint check.
+	ForeignKeyChecks bool
+
+	// RangeMaxSize is the max memory limit for ranges. When the optimizer estimates that the memory usage of complete
+	// ranges would exceed the limit, it chooses less accurate ranges such as full range. 0 indicates that there is no
+	// memory limit for ranges.
+	RangeMaxSize int64
+
+	// LastPlanReplayerToken indicates the last plan replayer token
+	LastPlanReplayerToken string
+
+	// AnalyzePartitionMergeConcurrency indicates concurrency for merging partition stats
+	AnalyzePartitionMergeConcurrency int
+
+	HookContext
+}
+
+// GetPreparedStmtByName returns the prepared statement specified by stmtName.
+func (s *SessionVars) GetPreparedStmtByName(stmtName string) (interface{}, error) {
+	stmtID, ok := s.PreparedStmtNameToID[stmtName]
+	if !ok {
+		return nil, ErrStmtNotFound
+	}
+	return s.GetPreparedStmtByID(stmtID)
+}
+
+// GetPreparedStmtByID returns the prepared statement specified by stmtID.
+func (s *SessionVars) GetPreparedStmtByID(stmtID uint32) (interface{}, error) {
+	stmt, ok := s.PreparedStmts[stmtID]
+	if !ok {
+		return nil, ErrStmtNotFound
+	}
+	return stmt, nil
+>>>>>>> e8d265981a (statistics: support merge global topn in concurrency (#38358))
 }
 
 // InitStatementContext initializes a StatementContext, the object is reused to reduce allocation.

sessionctx/variable/sysvar.go

@@ -1866,6 +1866,7 @@ var defaultSysVars = []*SysVar{
 		s.EnablePseudoForOutdatedStats = TiDBOptOn(val)
 		return nil
 	}},
+<<<<<<< HEAD
 
 	{Scope: ScopeNone, Name: "version_compile_os", Value: runtime.GOOS},
 	{Scope: ScopeNone, Name: "version_compile_machine", Value: runtime.GOARCH},
@@ -1888,6 +1889,15 @@ var GAFunction4ExpressionIndex = map[string]struct{}{
 	ast.MD5:        {},
 	ast.Reverse:    {},
 	ast.VitessHash: {},
+=======
+	{
+		Scope: ScopeGlobal | ScopeSession, Name: TiDBMergePartitionStatsConcurrency, Value: strconv.FormatInt(DefTiDBMergePartitionStatsConcurrency, 10), Type: TypeInt, MinValue: 1, MaxValue: MaxConfigurableConcurrency,
+		SetSession: func(s *SessionVars, val string) error {
+			s.AnalyzePartitionMergeConcurrency = TidbOptInt(val, DefTiDBMergePartitionStatsConcurrency)
+			return nil
+		},
+	},
+>>>>>>> e8d265981a (statistics: support merge global topn in concurrency (#38358))
 }
 
 // FeedbackProbability points to the FeedbackProbability in statistics package.