stats: auto analyze on certain period of a day

sessionctx/variable/sysvar.go

@@ -623,6 +623,8 @@ var defaultSysVars = []*SysVar{
 	{ScopeSession, TiDBOptAggPushDown, boolToIntStr(DefOptAggPushDown)},
 	{ScopeGlobal | ScopeSession, TiDBBuildStatsConcurrency, strconv.Itoa(DefBuildStatsConcurrency)},
 	{ScopeGlobal, TiDBAutoAnalyzeRatio, strconv.FormatFloat(DefAutoAnalyzeRatio, 'f', -1, 64)},
+	{ScopeGlobal, TiDBAutoAnalyzeStartTime, DefAutoAnalyzeStartTime},
+	{ScopeGlobal, TiDBAutoAnalyzeEndTime, DefAutoAnalyzeEndTime},
 	{ScopeSession, TiDBChecksumTableConcurrency, strconv.Itoa(DefChecksumTableConcurrency)},
 	{ScopeGlobal | ScopeSession, TiDBDistSQLScanConcurrency, strconv.Itoa(DefDistSQLScanConcurrency)},
 	{ScopeGlobal | ScopeSession, TiDBOptInSubqUnFolding, boolToIntStr(DefOptInSubqUnfolding)},

sessionctx/variable/tidb_vars.go

@@ -38,6 +38,10 @@ const (
 	// Auto analyze will run if (table modify count)/(table row count) is greater than this value.
 	TiDBAutoAnalyzeRatio = "tidb_auto_analyze_ratio"
 
+	// Auto analyze will run if current time is within start time and end time.
+	TiDBAutoAnalyzeStartTime = "tidb_auto_analyze_start_time"
+	TiDBAutoAnalyzeEndTime   = "tidb_auto_analyze_end_time"
+
 	// tidb_checksum_table_concurrency is used to speed up the ADMIN CHECKSUM TABLE
 	// statement, when a table has multiple indices, those indices can be
 	// scanned concurrently, with the cost of higher system performance impact.
@@ -189,6 +193,8 @@ const (
 	DefDistSQLScanConcurrency        = 15
 	DefBuildStatsConcurrency         = 4
 	DefAutoAnalyzeRatio              = 0.5
+	DefAutoAnalyzeStartTime          = "00:00 UTC"
+	DefAutoAnalyzeEndTime            = "23:59 UTC"
 	DefChecksumTableConcurrency      = 4
 	DefSkipUTF8Check                 = false
 	DefOptAggPushDown                = false

statistics/update.go

@@ -601,12 +601,28 @@ func TableAnalyzed(tbl *Table) bool {
 	return false
 }
 
-// needAnalyzeTable checks if we need to analyze the table:
+// withinTimePeriod tests whether `now` is between `start` and `end`.
+func withinTimePeriod(start, end, now time.Time) bool {
+	// Converts to UTC and only keeps the hour and minute info.
+	start, end, now = start.UTC(), end.UTC(), now.UTC()
+	start = time.Date(0, 0, 0, start.Hour(), start.Minute(), 0, 0, time.UTC)
+	end = time.Date(0, 0, 0, end.Hour(), end.Minute(), 0, 0, time.UTC)
+	now = time.Date(0, 0, 0, now.Hour(), now.Minute(), 0, 0, time.UTC)
+	// for cases like from 00:00 to 06:00
+	if end.Sub(start) >= 0 {
+		return now.Sub(start) >= 0 && now.Sub(end) <= 0
+	}
+	// for cases like from 22:00 to 06:00
+	return now.Sub(end) <= 0 || now.Sub(start) >= 0
+}
+
+// NeedAnalyzeTable checks if we need to analyze the table:
 // 1. If the table has never been analyzed, we need to analyze it when it has
 //    not been modified for a time.
 // 2. If the table had been analyzed before, we need to analyze it when
 //    "tbl.ModifyCount/tbl.Count > autoAnalyzeRatio".
-func needAnalyzeTable(tbl *Table, limit time.Duration, autoAnalyzeRatio float64) bool {
+// 3. The current time is between `start` and `end`.
+func NeedAnalyzeTable(tbl *Table, limit time.Duration, autoAnalyzeRatio float64, start, end, now time.Time) bool {
 	analyzed := TableAnalyzed(tbl)
 	if !analyzed {
 		t := time.Unix(0, oracle.ExtractPhysical(tbl.Version)*int64(time.Millisecond))
@@ -616,34 +632,63 @@ func needAnalyzeTable(tbl *Table, limit time.Duration, autoAnalyzeRatio float64)
 	if autoAnalyzeRatio == 0 {
 		return false
 	}
-	return float64(tbl.ModifyCount)/float64(tbl.Count) > autoAnalyzeRatio
+	// No need to analyze it.
+	if float64(tbl.ModifyCount)/float64(tbl.Count) <= autoAnalyzeRatio {
+		return false
+	}
+	// Tests if current time is within the time period.
+	return withinTimePeriod(start, end, now)
 }
 
-const minAutoAnalyzeRatio = 0.3
+const (
+	minAutoAnalyzeRatio = 0.3
+	// TimeFormat is the format of auto analyze start time and end time.
+	TimeFormat = "15:04 MST"
+)
 
-func (h *Handle) getAutoAnalyzeRatio() float64 {
-	sql := fmt.Sprintf("select variable_value from mysql.global_variables where variable_name = '%s'", variable.TiDBAutoAnalyzeRatio)
+func (h *Handle) getAutoAnalyzeParameters() map[string]string {
+	sql := fmt.Sprintf("select variable_name, variable_value from mysql.global_variables where variable_name in ('%s', '%s', '%s')",
+		variable.TiDBAutoAnalyzeRatio, variable.TiDBAutoAnalyzeStartTime, variable.TiDBAutoAnalyzeEndTime)
 	rows, _, err := h.restrictedExec.ExecRestrictedSQL(nil, sql)
 	if err != nil {
-		return variable.DefAutoAnalyzeRatio
+		return map[string]string{}
 	}
-	autoAnalyzeRatio := variable.DefAutoAnalyzeRatio
-	if len(rows) > 0 {
-		autoAnalyzeRatio, err = strconv.ParseFloat(rows[0].GetString(0), 64)
-		if err != nil {
-			return variable.DefAutoAnalyzeRatio
-		}
+	parameters := make(map[string]string)
+	for _, row := range rows {
+		parameters[row.GetString(0)] = row.GetString(1)
+	}
+	return parameters
+}
+
+func parseAutoAnalyzeRatio(ratio string) float64 {
+	autoAnalyzeRatio, err := strconv.ParseFloat(ratio, 64)
+	if err != nil {
+		return variable.DefAutoAnalyzeRatio
 	}
 	if autoAnalyzeRatio > 0 {
 		autoAnalyzeRatio = math.Max(autoAnalyzeRatio, minAutoAnalyzeRatio)
 	}
 	return autoAnalyzeRatio
 }
 
+func parseAnalyzePeriod(start, end string) (time.Time, time.Time) {
+	s, err := time.ParseInLocation(TimeFormat, start, time.UTC)
+	if err != nil {
+		s = time.Date(0, 0, 0, 0, 0, 0, 0, time.UTC)
+	}
+	e, err := time.ParseInLocation(TimeFormat, end, time.UTC)
+	if err != nil {
+		e = time.Date(0, 0, 0, 23, 59, 0, 0, time.UTC)
+	}
+	return s, e
+}
+
 // HandleAutoAnalyze analyzes the newly created table or index.
 func (h *Handle) HandleAutoAnalyze(is infoschema.InfoSchema) error {
 	dbs := is.AllSchemaNames()
-	autoAnalyzeRatio := h.getAutoAnalyzeRatio()
+	parameters := h.getAutoAnalyzeParameters()
+	autoAnalyzeRatio := parseAutoAnalyzeRatio(parameters[variable.TiDBAutoAnalyzeRatio])
+	start, end := parseAnalyzePeriod(parameters[variable.TiDBAutoAnalyzeStartTime], parameters[variable.TiDBAutoAnalyzeEndTime])
 	for _, db := range dbs {
 		tbls := is.SchemaTables(model.NewCIStr(db))
 		for _, tbl := range tbls {
@@ -653,7 +698,7 @@ func (h *Handle) HandleAutoAnalyze(is infoschema.InfoSchema) error {
 				continue
 			}
 			tblName := "`" + db + "`.`" + tblInfo.Name.O + "`"
-			if needAnalyzeTable(statsTbl, 20*h.Lease, autoAnalyzeRatio) {
+			if NeedAnalyzeTable(statsTbl, 20*h.Lease, autoAnalyzeRatio, start, end, time.Now()) {
 				sql := fmt.Sprintf("analyze table %s", tblName)
 				log.Infof("[stats] auto analyze table %s now", tblName)
 				return errors.Trace(h.execAutoAnalyze(sql))

statistics/update_test.go

@@ -26,6 +26,7 @@ import (
 	"github.com/pingcap/tidb/mysql"
 	"github.com/pingcap/tidb/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/statistics"
+	"github.com/pingcap/tidb/store/tikv/oracle"
 	"github.com/pingcap/tidb/types"
 	"github.com/pingcap/tidb/util/codec"
 	"github.com/pingcap/tidb/util/ranger"
@@ -918,3 +919,107 @@ func (s *testStatsUpdateSuite) TestLogDetailedInfo(c *C) {
 		c.Assert(s.hook.results, Equals, t.result)
 	}
 }
+
+func (s *testStatsUpdateSuite) TestNeedAnalyzeTable(c *C) {
+	columns := map[int64]*statistics.Column{}
+	columns[1] = &statistics.Column{Count: 1}
+	tests := []struct {
+		tbl    *statistics.Table
+		ratio  float64
+		limit  time.Duration
+		start  string
+		end    string
+		now    string
+		result bool
+	}{
+		// table never analyzed and has reach the limit
+		{
+			tbl:    &statistics.Table{Version: oracle.EncodeTSO(oracle.GetPhysical(time.Now()))},
+			limit:  0,
+			ratio:  0,
+			start:  "00:00 CST",
+			end:    "00:01 CST",
+			now:    "00:00 CST",
+			result: true,
+		},
+		// table never analyzed but has not reach the limit
+		{
+			tbl:    &statistics.Table{Version: oracle.EncodeTSO(oracle.GetPhysical(time.Now()))},
+			limit:  time.Hour,
+			ratio:  0,
+			start:  "00:00 CST",
+			end:    "00:01 CST",
+			now:    "00:00 CST",
+			result: false,
+		},
+		// table already analyzed but auto analyze is disabled
+		{
+			tbl:    &statistics.Table{HistColl: statistics.HistColl{Columns: columns, ModifyCount: 1, Count: 1}},
+			limit:  0,
+			ratio:  0,
+			start:  "00:00 CST",
+			end:    "00:01 CST",
+			now:    "00:00 CST",
+			result: false,
+		},
+		// table already analyzed and but modify count is small
+		{
+			tbl:    &statistics.Table{HistColl: statistics.HistColl{Columns: columns, ModifyCount: 0, Count: 1}},
+			limit:  0,
+			ratio:  0.3,
+			start:  "00:00 CST",
+			end:    "00:01 CST",
+			now:    "00:00 CST",
+			result: false,
+		},
+		// table already analyzed and but not within time period
+		{
+			tbl:    &statistics.Table{HistColl: statistics.HistColl{Columns: columns, ModifyCount: 1, Count: 1}},
+			limit:  0,
+			ratio:  0.3,
+			start:  "00:00 CST",
+			end:    "00:01 CST",
+			now:    "00:02 CST",
+			result: false,
+		},
+		// table already analyzed and but not within time period
+		{
+			tbl:    &statistics.Table{HistColl: statistics.HistColl{Columns: columns, ModifyCount: 1, Count: 1}},
+			limit:  0,
+			ratio:  0.3,
+			start:  "22:00 CST",
+			end:    "06:00 CST",
+			now:    "10:00 CST",
+			result: false,
+		},
+		// table already analyzed and within time period
+		{
+			tbl:    &statistics.Table{HistColl: statistics.HistColl{Columns: columns, ModifyCount: 1, Count: 1}},
+			limit:  0,
+			ratio:  0.3,
+			start:  "00:00 CST",
+			end:    "00:01 CST",
+			now:    "00:00 CST",
+			result: true,
+		},
+		// table already analyzed and within time period
+		{
+			tbl:    &statistics.Table{HistColl: statistics.HistColl{Columns: columns, ModifyCount: 1, Count: 1}},
+			limit:  0,
+			ratio:  0.3,
+			start:  "22:00 CST",
+			end:    "06:00 CST",
+			now:    "23:00 CST",
+			result: true,
+		},
+	}
+	for _, test := range tests {
+		start, err := time.ParseInLocation(statistics.TimeFormat, test.start, time.UTC)
+		c.Assert(err, IsNil)
+		end, err := time.ParseInLocation(statistics.TimeFormat, test.end, time.UTC)
+		c.Assert(err, IsNil)
+		now, err := time.ParseInLocation(statistics.TimeFormat, test.now, time.UTC)
+		c.Assert(err, IsNil)
+		c.Assert(statistics.NeedAnalyzeTable(test.tbl, test.limit, test.ratio, start, end, now), Equals, test.result)
+	}
+}