address comment

server/statistics_handler.go

@@ -14,10 +14,10 @@
 package server
 
 import (
+	"errors"
 	"net/http"
 	"time"
 
-	"context"
 	"github.com/gorilla/mux"
 	"github.com/pingcap/parser/model"
 	"github.com/pingcap/parser/mysql"
@@ -26,9 +26,7 @@ import (
 	"github.com/pingcap/tidb/sessionctx/variable"
 	"github.com/pingcap/tidb/types"
 	"github.com/pingcap/tidb/util/gcutil"
-	"github.com/pingcap/tidb/util/logutil"
 	"github.com/pingcap/tidb/util/sqlexec"
-	"go.uber.org/zap"
 )
 
 // StatsHandler is the handler for dumping statistics.
@@ -39,17 +37,21 @@ type StatsHandler struct {
 func (s *Server) newStatsHandler() *StatsHandler {
 	store, ok := s.driver.(*TiDBDriver)
 	if !ok {
-		logutil.Logger(context.Background()).Error("Illegal driver")
+		panic("Illegal driver")
 	}
 
 	do, err := session.GetDomain(store.store)
 	if err != nil {
-		logutil.Logger(context.Background()).Error("Failed to get domain", zap.Error(err))
+		panic("Failed to get domain")
 	}
 	return &StatsHandler{do}
 }
 
 func (sh StatsHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	if req.Method != http.MethodGet {
+		writeError(w, errors.New("only http GET method is supported"))
+		return
+	}
 	w.Header().Set("Content-Type", "application/json")
 
 	params := mux.Vars(req)
@@ -88,6 +90,10 @@ func (s *Server) newStatsHistoryHandler() *StatsHistoryHandler {
 }
 
 func (sh StatsHistoryHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	if req.Method != http.MethodGet {
+		writeError(w, errors.New("only http GET method is supported"))
+		return
+	}
 	w.Header().Set("Content-Type", "application/json")
 
 	params := mux.Vars(req)

server/statistics_handler_test.go

@@ -31,6 +31,7 @@ import (
 	"github.com/pingcap/tidb/statistics/handle"
 	"github.com/pingcap/tidb/store/mockstore"
 	"github.com/pingcap/tidb/store/mockstore/mocktikv"
+	"github.com/sirupsen/logrus"
 )
 
 type testDumpStatsSuite struct {
@@ -130,6 +131,7 @@ func (ds *testDumpStatsSuite) TestDumpStatsAPI(c *C) {
 		c.Assert(os.Remove(path1), IsNil)
 	}()
 
+	logrus.Warning("after snapshot")
 	resp1, err = http.Get("http://127.0.0.1:10090/stats/dump/tidb/test/" + snapshot)
 	c.Assert(err, IsNil)
 

statistics/handle/dump.go

@@ -25,6 +25,7 @@ import (
 	"github.com/pingcap/tidb/types"
 	"github.com/pingcap/tidb/util/sqlexec"
 	"github.com/pingcap/tipb/go-tipb"
+	"github.com/sirupsen/logrus"
 )
 
 // JSONTable is used for dumping statistics.
@@ -85,12 +86,14 @@ func (h *Handle) DumpStatsToJSON(dbName string, tableInfo *model.TableInfo, hist
 
 func (h *Handle) tableStatsToJSON(dbName string, tableInfo *model.TableInfo, physicalID int64, historyStatsExec sqlexec.RestrictedSQLExecutor) (*JSONTable, error) {
 	tbl, err := h.tableStatsFromStorage(tableInfo, physicalID, true, historyStatsExec)
-	if err != nil {
-		return nil, errors.Trace(err)
+	if err != nil || tbl == nil {
+		return nil, err
 	}
-	if tbl == nil {
-		return nil, nil
+	tbl.Version, tbl.ModifyCount, tbl.Count, err = h.statsMetaByTableIDFromStorage(physicalID, historyStatsExec)
+	if err != nil {
+		return nil, err
 	}
+	logrus.Warning("tbl.ModifyCount", tbl.ModifyCount, "tbl.Indices", len(tbl.Indices))
 	jsonTbl := &JSONTable{
 		DatabaseName: dbName,
 		TableName:    tableInfo.Name.L,

statistics/handle/handle.go

@@ -35,6 +35,7 @@ import (
 	"github.com/pingcap/tidb/util/chunk"
 	"github.com/pingcap/tidb/util/logutil"
 	"github.com/pingcap/tidb/util/sqlexec"
+	"github.com/sirupsen/logrus"
 	atomic2 "go.uber.org/atomic"
 	"go.uber.org/zap"
 )
@@ -354,6 +355,7 @@ func (h *Handle) indexStatsFromStorage(row chunk.Row, table *statistics.Table, t
 			continue
 		}
 		if idx == nil || idx.LastUpdateVersion < histVer {
+			logrus.Warning("go into this")
 			hg, err := h.histogramFromStorage(table.PhysicalID, histID, types.NewFieldType(mysql.TypeBlob), distinct, 1, histVer, nullCount, 0, 0, historyStatsExec)
 			if err != nil {
 				return errors.Trace(err)
@@ -404,6 +406,7 @@ func (h *Handle) columnStatsFromStorage(row chunk.Row, table *statistics.Table,
 			!isHandle &&
 			(col == nil || col.Len() == 0 && col.LastUpdateVersion < histVer) &&
 			!loadAll
+		logrus.Warning("notNeedLoad", notNeedLoad)
 		if notNeedLoad {
 			count, err := h.columnCountFromStorage(table.PhysicalID, histID)
 			if err != nil {
@@ -463,7 +466,7 @@ func (h *Handle) tableStatsFromStorage(tableInfo *model.TableInfo, physicalID in
 	table, ok := h.StatsCache.Load().(StatsCache)[physicalID]
 	// If table stats is pseudo, we also need to copy it, since we will use the column stats when
 	// the average error rate of it is small.
-	if !ok {
+	if !ok || historyStatsExec != nil {
 		histColl := statistics.HistColl{
 			PhysicalID:     physicalID,
 			HavePhysicalID: true,
@@ -673,3 +676,20 @@ func (h *Handle) columnCountFromStorage(tableID, colID int64) (int64, error) {
 	}
 	return rows[0].GetMyDecimal(0).ToInt()
 }
+
+func (h *Handle) statsMetaByTableIDFromStorage(tableID int64, historyStatsExec sqlexec.RestrictedSQLExecutor) (version uint64, modifyCount, count int64, err error) {
+	selSQL := fmt.Sprintf("SELECT version, modify_count, count from mysql.stats_meta where table_id = %d order by version", tableID)
+	var rows []chunk.Row
+	if historyStatsExec == nil {
+		rows, _, err = h.restrictedExec.ExecRestrictedSQL(nil, selSQL)
+	} else {
+		rows, _, err = historyStatsExec.ExecRestrictedSQLWithSnapshot(nil, selSQL)
+	}
+	if err != nil || len(rows) == 0 {
+		return
+	}
+	version = rows[0].GetUint64(0)
+	modifyCount = rows[0].GetInt64(1)
+	count = rows[0].GetInt64(2)
+	return
+}