planner,executor,infoschema: add system tables tiflash_tables and tiflash_segments

executor/builder.go

@@ -1489,6 +1489,17 @@ func (b *executorBuilder) buildMemTable(v *plannercore.PhysicalMemTable) Executo
 				baseExecutor: newBaseExecutor(b.ctx, v.Schema(), v.ExplainID()),
 				is:           b.is,
 			}
+		case strings.ToLower(infoschema.TableTiFlashTables),
+			strings.ToLower(infoschema.TableTiFlashSegments):
+			return &MemTableReaderExec{
+				baseExecutor: newBaseExecutor(b.ctx, v.Schema(), v.ExplainID()),
+				table:        v.Table,
+				retriever: &TiFlashSystemTableRetriever{
+					table:      v.Table,
+					outputCols: v.Columns,
+					extractor:  v.Extractor.(*plannercore.TiFlashSystemTableExtractor),
+				},
+			}
 		}
 	}
 	tb, _ := b.is.TableByID(v.Table.ID)

executor/explainfor_test.go

@@ -301,3 +301,26 @@ func (s *testSuite) TestInspectionSummaryTable(c *C) {
 		`└─MemTableScan_6 10000.00 root table:INSPECTION_SUMMARY skip_inspection: true`,
 	))
 }
+
+func (s *testSuite) TestExplainTiFlashSystemTables(c *C) {
+	tk := testkit.NewTestKitWithInit(c, s.store)
+	tiflashInstance := "192.168.1.7:3930"
+	database := "test"
+	table := "t"
+	tk.MustQuery(fmt.Sprintf("desc select * from information_schema.TIFLASH_TABLES where TIFLASH_INSTANCE = '%s'", tiflashInstance)).Check(testkit.Rows(
+		fmt.Sprintf("MemTableScan_5 10000.00 root table:TIFLASH_TABLES tiflash_instances:[\"%s\"]", tiflashInstance)))
+	tk.MustQuery(fmt.Sprintf("desc select * from information_schema.TIFLASH_SEGMENTS where TIFLASH_INSTANCE = '%s'", tiflashInstance)).Check(testkit.Rows(
+		fmt.Sprintf("MemTableScan_5 10000.00 root table:TIFLASH_SEGMENTS tiflash_instances:[\"%s\"]", tiflashInstance)))
+	tk.MustQuery(fmt.Sprintf("desc select * from information_schema.TIFLASH_TABLES where TIDB_DATABASE = '%s'", database)).Check(testkit.Rows(
+		fmt.Sprintf("MemTableScan_5 10000.00 root table:TIFLASH_TABLES tidb_databases:[\"%s\"]", database)))
+	tk.MustQuery(fmt.Sprintf("desc select * from information_schema.TIFLASH_SEGMENTS where TIDB_DATABASE = '%s'", database)).Check(testkit.Rows(
+		fmt.Sprintf("MemTableScan_5 10000.00 root table:TIFLASH_SEGMENTS tidb_databases:[\"%s\"]", database)))
+	tk.MustQuery(fmt.Sprintf("desc select * from information_schema.TIFLASH_TABLES where TIDB_TABLE = '%s'", table)).Check(testkit.Rows(
+		fmt.Sprintf("MemTableScan_5 10000.00 root table:TIFLASH_TABLES tidb_tables:[\"%s\"]", table)))
+	tk.MustQuery(fmt.Sprintf("desc select * from information_schema.TIFLASH_SEGMENTS where TIDB_TABLE = '%s'", table)).Check(testkit.Rows(
+		fmt.Sprintf("MemTableScan_5 10000.00 root table:TIFLASH_SEGMENTS tidb_tables:[\"%s\"]", table)))
+	tk.MustQuery(fmt.Sprintf("desc select * from information_schema.TIFLASH_TABLES where TIFLASH_INSTANCE = '%s' and TIDB_DATABASE = '%s' and TIDB_TABLE = '%s'", tiflashInstance, database, table)).Check(testkit.Rows(
+		fmt.Sprintf("MemTableScan_5 10000.00 root table:TIFLASH_TABLES tiflash_instances:[\"%s\"], tidb_databases:[\"%s\"], tidb_tables:[\"%s\"]", tiflashInstance, database, table)))
+	tk.MustQuery(fmt.Sprintf("desc select * from information_schema.TIFLASH_SEGMENTS where TIFLASH_INSTANCE = '%s' and TIDB_DATABASE = '%s' and TIDB_TABLE = '%s'", tiflashInstance, database, table)).Check(testkit.Rows(
+		fmt.Sprintf("MemTableScan_5 10000.00 root table:TIFLASH_SEGMENTS tiflash_instances:[\"%s\"], tidb_databases:[\"%s\"], tidb_tables:[\"%s\"]", tiflashInstance, database, table)))
+}

executor/infoschema_reader.go

@@ -17,7 +17,10 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io/ioutil"
+	"net/http"
 	"sort"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -27,6 +30,8 @@ import (
 	"github.com/pingcap/parser/charset"
 	"github.com/pingcap/parser/model"
 	"github.com/pingcap/parser/mysql"
+	"github.com/pingcap/parser/terror"
+	"github.com/pingcap/tidb/domain"
 	"github.com/pingcap/tidb/domain/infosync"
 	"github.com/pingcap/tidb/infoschema"
 	"github.com/pingcap/tidb/meta/autoid"
@@ -47,6 +52,7 @@ import (
 	"github.com/pingcap/tidb/util/set"
 	"github.com/pingcap/tidb/util/sqlexec"
 	"github.com/pingcap/tidb/util/stmtsummary"
+	"go.etcd.io/etcd/clientv3"
 )
 
 type memtableRetriever struct {
@@ -1760,3 +1766,178 @@ func (e *memtableRetriever) setDataForStatementsSummary(ctx sessionctx.Context,
 	}
 	return nil
 }
+
+// TiFlashSystemTableRetriever is used to read system table from tiflash.
+type TiFlashSystemTableRetriever struct {
+	dummyCloser
+	table         *model.TableInfo
+	outputCols    []*model.ColumnInfo
+	instanceCount int
+	instanceIdx   int
+	instanceInfos []tiflashInstanceInfo
+	rowIdx        int
+	retrieved     bool
+	initialized   bool
+	extractor     *plannercore.TiFlashSystemTableExtractor
+}
+
+func (e *TiFlashSystemTableRetriever) retrieve(ctx context.Context, sctx sessionctx.Context) ([][]types.Datum, error) {
+	if e.extractor.SkipRequest || e.retrieved {
+		return nil, nil
+	}
+	if !e.initialized {
+		err := e.initialize(sctx, e.extractor.TiFlashInstances)
+		if err != nil {
+			return nil, err
+		}
+	}
+	if e.instanceCount == 0 || e.instanceIdx >= e.instanceCount {
+		e.retrieved = true
+		return nil, nil
+	}
+
+	for {
+		rows, err := e.dataForTiFlashSystemTables(sctx, e.extractor.TiDBDatabases, e.extractor.TiDBTables)
+		if err != nil {
+			return nil, err
+		}
+		if len(rows) > 0 || e.instanceIdx >= e.instanceCount {
+			return rows, nil
+		}
+	}
+}
+
+type tiflashInstanceInfo struct {
+	id  string
+	url string
+}
+
+func (e *TiFlashSystemTableRetriever) initialize(sctx sessionctx.Context, tiflashInstances set.StringSet) error {
+	store := sctx.GetStore()
+	if etcd, ok := store.(tikv.EtcdBackend); ok {
+		if addrs := etcd.EtcdAddrs(); addrs != nil {
+			domainFromCtx := domain.GetDomain(sctx)
+			if domainFromCtx != nil {
+				cli := domainFromCtx.GetEtcdClient()
+				prefix := "/tiflash/cluster/http_port/"
+				kv := clientv3.NewKV(cli)
+				ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+				resp, err := kv.Get(ctx, prefix, clientv3.WithPrefix())
+				cancel()
+				if err != nil {
+					return errors.Trace(err)
+				}
+				for _, ev := range resp.Kvs {
+					id := string(ev.Key)[len(prefix):]
+					if len(tiflashInstances) > 0 && !tiflashInstances.Exist(id) {
+						continue
+					}
+					// TODO: Support https in tiflash
+					url := fmt.Sprintf("http://%s", ev.Value)
+					e.instanceInfos = append(e.instanceInfos, tiflashInstanceInfo{
+						id:  id,
+						url: url,
+					})
+					e.instanceCount += 1
+				}
+				e.initialized = true
+				return nil
+			}
+			return errors.Errorf("Etcd client not found")
+		}
+		return errors.Errorf("Etcd addrs not found")
+	}
+	return errors.Errorf("%T not an etcd backend", store)
+}
+
+func (e *TiFlashSystemTableRetriever) dataForTiFlashSystemTables(ctx sessionctx.Context, tidbDatabases string, tidbTables string) ([][]types.Datum, error) {
+	var columnNames []string
+	for _, c := range e.outputCols {
+		if c.Name.O == "TIFLASH_INSTANCE" {
+			continue
+		}
+		columnNames = append(columnNames, c.Name.L)
+	}
+	maxCount := 1024
+	targetTable := strings.ToLower(strings.Replace(e.table.Name.O, "TIFLASH", "DT", 1))
+	var filters []string
+	if len(tidbDatabases) > 0 {
+		filters = append(filters, fmt.Sprintf("tidb_database IN (%s)", strings.ReplaceAll(tidbDatabases, "\"", "'")))
+	}
+	if len(tidbTables) > 0 {
+		filters = append(filters, fmt.Sprintf("tidb_table IN (%s)", strings.ReplaceAll(tidbTables, "\"", "'")))
+	}
+	sql := fmt.Sprintf("SELECT %s FROM system.%s", strings.Join(columnNames, ","), targetTable)
+	if len(filters) > 0 {
+		sql = fmt.Sprintf("%s WHERE %s", sql, strings.Join(filters, " AND "))
+	}
+	sql = fmt.Sprintf("%s LIMIT %d, %d", sql, e.rowIdx, maxCount)
+	notNumber := "nan"
+	httpClient := http.DefaultClient
+	instanceInfo := e.instanceInfos[e.instanceIdx]
+	url := instanceInfo.url
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	if err != nil {
+		return nil, errors.Trace(err)
+	}
+	q := req.URL.Query()
+	q.Add("query", sql)
+	req.URL.RawQuery = q.Encode()
+	resp, err := httpClient.Do(req)
+	if err != nil {
+		return nil, errors.Trace(err)
+	}
+	body, err := ioutil.ReadAll(resp.Body)
+	terror.Log(resp.Body.Close())
+	if err != nil {
+		return nil, errors.Trace(err)
+	}
+	records := strings.Split(string(body), "\n")
+	var rows [][]types.Datum
+	for _, record := range records {
+		if len(record) == 0 {
+			continue
+		}
+		fields := strings.Split(record, "\t")
+		if len(fields) < len(e.outputCols)-1 {
+			return nil, errors.Errorf("Record from tiflash doesn't match schema %v", fields)
+		}
+		row := make([]types.Datum, len(e.outputCols))
+		for index, column := range e.outputCols {
+			if column.Name.O == "TIFLASH_INSTANCE" {
+				continue
+			}
+			if column.Tp == mysql.TypeVarchar {
+				row[index].SetString(fields[index], mysql.DefaultCollationName)
+			} else if column.Tp == mysql.TypeLonglong {
+				if fields[index] == notNumber {
+					continue
+				}
+				value, err := strconv.ParseInt(fields[index], 10, 64)
+				if err != nil {
+					return nil, errors.Trace(err)
+				}
+				row[index].SetInt64(value)
+			} else if column.Tp == mysql.TypeDouble {
+				if fields[index] == notNumber {
+					continue
+				}
+				value, err := strconv.ParseFloat(fields[index], 64)
+				if err != nil {
+					return nil, errors.Trace(err)
+				}
+				row[index].SetFloat64(value)
+			} else {
+				return nil, errors.Errorf("Meet column of unknown type %v", column)
+			}
+		}
+		row[len(e.outputCols)-1].SetString(instanceInfo.id, mysql.DefaultCollationName)
+		rows = append(rows, row)
+	}
+	e.rowIdx += len(rows)
+	if len(rows) < maxCount {
+		e.instanceIdx += 1
+		e.rowIdx = 0
+	}
+	return rows, nil
+}

executor/infoschema_reader_test.go

@@ -812,3 +812,11 @@ func (s *testInfoschemaTableSuite) TestSequences(c *C) {
 	tk.MustExec("CREATE SEQUENCE test.seq2 start = -9 minvalue -10 maxvalue 10 increment -1 cache 15")
 	tk.MustQuery("SELECT * FROM information_schema.sequences WHERE sequence_schema='test' AND sequence_name='seq2'").Check(testkit.Rows("def test seq2 1 15 0 -1 10 -10 -9 "))
 }
+
+func (s *testInfoschemaTableSuite) TestTiFlashSystemTables(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	err := tk.QueryToErr("select * from information_schema.TIFLASH_TABLES;")
+	c.Assert(err.Error(), Equals, "Etcd addrs not found")
+	err = tk.QueryToErr("select * from information_schema.TIFLASH_SEGMENTS;")
+	c.Assert(err.Error(), Equals, "Etcd addrs not found")
+}

infoschema/tables.go

@@ -147,6 +147,10 @@ const (
 	TableStatementsSummaryHistory = "STATEMENTS_SUMMARY_HISTORY"
 	// TableStorageStats is a table that contains all tables disk usage
 	TableStorageStats = "TABLE_STORAGE_STATS"
+	// TableTiFlashTables is the string constant of tiflash tables table.
+	TableTiFlashTables = "TIFLASH_TABLES"
+	// TableTiFlashSegments is the string constant of tiflash segments table.
+	TableTiFlashSegments = "TIFLASH_SEGMENTS"
 )
 
 var tableIDMap = map[string]int64{
@@ -213,6 +217,8 @@ var tableIDMap = map[string]int64{
 	ClusterTableStatementsSummary:           autoid.InformationSchemaDBID + 61,
 	ClusterTableStatementsSummaryHistory:    autoid.InformationSchemaDBID + 62,
 	TableStorageStats:                       autoid.InformationSchemaDBID + 63,
+	TableTiFlashTables:                      autoid.InformationSchemaDBID + 64,
+	TableTiFlashSegments:                    autoid.InformationSchemaDBID + 65,
 }
 
 type columnInfo struct {
@@ -1128,6 +1134,85 @@ var tableStorageStatsCols = []columnInfo{
 	{name: "TABLE_KEYS", tp: mysql.TypeLonglong, size: 64, comment: "The count of keys of single replica of the table"},
 }
 
+var tableTableTiFlashTablesCols = []columnInfo{
+	{name: "DATABASE", tp: mysql.TypeVarchar, size: 64},
+	{name: "TABLE", tp: mysql.TypeVarchar, size: 64},
+	{name: "TIDB_DATABASE", tp: mysql.TypeVarchar, size: 64},
+	{name: "TIDB_TABLE", tp: mysql.TypeVarchar, size: 64},
+	{name: "TABLE_ID", tp: mysql.TypeLonglong, size: 64},
+	{name: "IS_TOMBSTONE", tp: mysql.TypeLonglong, size: 64},
+	{name: "SEGMENT_COUNT", tp: mysql.TypeLonglong, size: 64},
+	{name: "TOTAL_ROWS", tp: mysql.TypeLonglong, size: 64},
+	{name: "TOTAL_SIZE", tp: mysql.TypeLonglong, size: 64},
+	{name: "TOTAL_DELETE_RANGES", tp: mysql.TypeLonglong, size: 64},
+	{name: "DELTA_RATE_ROWS", tp: mysql.TypeDouble, size: 64},
+	{name: "DELTA_RATE_SEGMENTS", tp: mysql.TypeDouble, size: 64},
+	{name: "DELTA_PLACED_RATE", tp: mysql.TypeDouble, size: 64},
+	{name: "DELTA_CACHE_SIZE", tp: mysql.TypeLonglong, size: 64},
+	{name: "DELTA_CACHE_RATE", tp: mysql.TypeDouble, size: 64},
+	{name: "DELTA_CACHE_WASTED_RATE", tp: mysql.TypeDouble, size: 64},
+	{name: "DELTA_INDEX_SIZE", tp: mysql.TypeLonglong, size: 64},
+	{name: "AVG_SEGMENT_ROWS", tp: mysql.TypeDouble, size: 64},
+	{name: "AVG_SEGMENT_SIZE", tp: mysql.TypeDouble, size: 64},
+	{name: "DELTA_COUNT", tp: mysql.TypeLonglong, size: 64},
+	{name: "TOTAL_DELTA_ROWS", tp: mysql.TypeLonglong, size: 64},
+	{name: "TOTAL_DELTA_SIZE", tp: mysql.TypeLonglong, size: 64},
+	{name: "AVG_DELTA_ROWS", tp: mysql.TypeDouble, size: 64},
+	{name: "AVG_DELTA_SIZE", tp: mysql.TypeDouble, size: 64},
+	{name: "AVG_DELTA_DELETE_RANGES", tp: mysql.TypeDouble, size: 64},
+	{name: "STABLE_COUNT", tp: mysql.TypeLonglong, size: 64},
+	{name: "TOTAL_STABLE_ROWS", tp: mysql.TypeLonglong, size: 64},
+	{name: "TOTAL_STABLE_SIZE", tp: mysql.TypeLonglong, size: 64},
+	{name: "TOTAL_STABLE_SIZE_ON_DISK", tp: mysql.TypeLonglong, size: 64},
+	{name: "AVG_STABLE_ROWS", tp: mysql.TypeDouble, size: 64},
+	{name: "AVG_STABLE_SIZE", tp: mysql.TypeDouble, size: 64},
+	{name: "TOTAL_PACK_COUNT_IN_DELTA", tp: mysql.TypeLonglong, size: 64},
+	{name: "AVG_PACK_COUNT_IN_DELTA", tp: mysql.TypeDouble, size: 64},
+	{name: "AVG_PACK_ROWS_IN_DELTA", tp: mysql.TypeDouble, size: 64},
+	{name: "AVG_PACK_SIZE_IN_DELTA", tp: mysql.TypeDouble, size: 64},
+	{name: "TOTAL_PACK_COUNT_IN_STABLE", tp: mysql.TypeLonglong, size: 64},
+	{name: "AVG_PACK_COUNT_IN_STABLE", tp: mysql.TypeDouble, size: 64},
+	{name: "AVG_PACK_ROWS_IN_STABLE", tp: mysql.TypeDouble, size: 64},
+	{name: "AVG_PACK_SIZE_IN_STABLE", tp: mysql.TypeDouble, size: 64},
+	{name: "STORAGE_STABLE_NUM_SNAPSHOTS", tp: mysql.TypeLonglong, size: 64},
+	{name: "STORAGE_STABLE_NUM_PAGES", tp: mysql.TypeLonglong, size: 64},
+	{name: "STORAGE_STABLE_NUM_NORMAL_PAGES", tp: mysql.TypeLonglong, size: 64},
+	{name: "STORAGE_STABLE_MAX_PAGE_ID", tp: mysql.TypeLonglong, size: 64},
+	{name: "STORAGE_DELTA_NUM_SNAPSHOTS", tp: mysql.TypeLonglong, size: 64},
+	{name: "STORAGE_DELTA_NUM_PAGES", tp: mysql.TypeLonglong, size: 64},
+	{name: "STORAGE_DELTA_NUM_NORMAL_PAGES", tp: mysql.TypeLonglong, size: 64},
+	{name: "STORAGE_DELTA_MAX_PAGE_ID", tp: mysql.TypeLonglong, size: 64},
+	{name: "STORAGE_META_NUM_SNAPSHOTS", tp: mysql.TypeLonglong, size: 64},
+	{name: "STORAGE_META_NUM_PAGES", tp: mysql.TypeLonglong, size: 64},
+	{name: "STORAGE_META_NUM_NORMAL_PAGES", tp: mysql.TypeLonglong, size: 64},
+	{name: "STORAGE_META_MAX_PAGE_ID", tp: mysql.TypeLonglong, size: 64},
+	{name: "BACKGROUND_TASKS_LENGTH", tp: mysql.TypeLonglong, size: 64},
+	{name: "TIFLASH_INSTANCE", tp: mysql.TypeVarchar, size: 64},
+}
+
+var tableTableTiFlashSegmentsCols = []columnInfo{
+	{name: "DATABASE", tp: mysql.TypeVarchar, size: 64},
+	{name: "TABLE", tp: mysql.TypeVarchar, size: 64},
+	{name: "TIDB_DATABASE", tp: mysql.TypeVarchar, size: 64},
+	{name: "TIDB_TABLE", tp: mysql.TypeVarchar, size: 64},
+	{name: "TABLE_ID", tp: mysql.TypeLonglong, size: 64},
+	{name: "IS_TOMBSTONE", tp: mysql.TypeLonglong, size: 64},
+	{name: "SEGMENT_ID", tp: mysql.TypeLonglong, size: 64},
+	{name: "RANGE", tp: mysql.TypeVarchar, size: 64},
+	{name: "ROWS", tp: mysql.TypeLonglong, size: 64},
+	{name: "SIZE", tp: mysql.TypeLonglong, size: 64},
+	{name: "DELETE_RANGES", tp: mysql.TypeLonglong, size: 64},
+	{name: "STABLE_SIZE_ON_DISK", tp: mysql.TypeLonglong, size: 64},
+	{name: "DELTA_PACK_COUNT", tp: mysql.TypeLonglong, size: 64},
+	{name: "STABLE_PACK_COUNT", tp: mysql.TypeLonglong, size: 64},
+	{name: "AVG_DELTA_PACK_ROWS", tp: mysql.TypeDouble, size: 64},
+	{name: "AVG_STABLE_PACK_ROWS", tp: mysql.TypeDouble, size: 64},
+	{name: "DELTA_RATE", tp: mysql.TypeDouble, size: 64},
+	{name: "DELTA_CACHE_SIZE", tp: mysql.TypeLonglong, size: 64},
+	{name: "DELTA_INDEX_SIZE", tp: mysql.TypeLonglong, size: 64},
+	{name: "TIFLASH_INSTANCE", tp: mysql.TypeVarchar, size: 64},
+}
+
 // GetShardingInfo returns a nil or description string for the sharding information of given TableInfo.
 // The returned description string may be:
 //  - "NOT_SHARDED": for tables that SHARD_ROW_ID_BITS is not specified.
@@ -1431,6 +1516,8 @@ var tableNameToColumns = map[string][]columnInfo{
 	TableStatementsSummary:                  tableStatementsSummaryCols,
 	TableStatementsSummaryHistory:           tableStatementsSummaryCols,
 	TableStorageStats:                       tableStorageStatsCols,
+	TableTiFlashTables:                      tableTableTiFlashTablesCols,
+	TableTiFlashSegments:                    tableTableTiFlashSegmentsCols,
 }
 
 func createInfoSchemaTable(_ autoid.Allocators, meta *model.TableInfo) (table.Table, error) {

planner/core/logical_plan_builder.go

@@ -3011,6 +3011,8 @@ func (b *PlanBuilder) buildMemTable(_ context.Context, dbName model.CIStr, table
 			p.Extractor = &SlowQueryExtractor{}
 		case infoschema.TableStorageStats:
 			p.Extractor = &TableStorageStatsExtractor{}
+		case infoschema.TableTiFlashTables, infoschema.TableTiFlashSegments:
+			p.Extractor = &TiFlashSystemTableExtractor{}
 		}
 	}
 	return p, nil