From 137ed650cc3fcd04ed31b4e7978dccebc087330d Mon Sep 17 00:00:00 2001
From: Ti Chi Robot <ti-community-prow-bot@tidb.io>
Date: Mon, 20 May 2024 21:02:46 +0800
Subject: [PATCH] snapshot (ticdc): reduce list tables time consumption
 (#11095) (#11126)

close pingcap/tiflow#11124
---
 cdc/entry/schema/snapshot.go | 37 +++++++++++++++++++++---------------
 1 file changed, 22 insertions(+), 15 deletions(-)

diff --git a/cdc/entry/schema/snapshot.go b/cdc/entry/schema/snapshot.go
index daf9e3078cb..e01821ef551 100644
--- a/cdc/entry/schema/snapshot.go
+++ b/cdc/entry/schema/snapshot.go
@@ -18,6 +18,7 @@ import (
 	"math"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/google/btree"
 	"github.com/pingcap/errors"
@@ -146,6 +147,7 @@ func NewSnapshotFromMeta(
 	forceReplicate bool,
 	filter filter.Filter,
 ) (*Snapshot, error) {
+	start := time.Now()
 	snap := NewEmptySnapshot(forceReplicate)
 	dbinfos, err := meta.ListDatabases()
 	if err != nil {
@@ -153,8 +155,6 @@ func NewSnapshotFromMeta(
 	}
 	// `tag` is used to reverse sort all versions in the generated snapshot.
 	tag := negative(currentTs)
-	// record all tables to be replicated for logging use
-	tables := make([]*model.TableInfo, 0, 1024)
 	for _, dbinfo := range dbinfos {
 		if filter.ShouldIgnoreSchema(dbinfo.Name.O) {
 			log.Debug("ignore database", zap.String("db", dbinfo.Name.O))
@@ -167,16 +167,30 @@ func NewSnapshotFromMeta(
 		vname := newVersionedEntityName(-1, dbinfo.Name.O, tag) // -1 means the entity is a schema.
 		vname.target = dbinfo.ID
 		snap.inner.schemaNameToID.ReplaceOrInsert(vname)
-
-		tableInfos, err := meta.ListTables(dbinfo.ID)
+		// get all tables Name
+		tableNames, err := meta.ListSimpleTables(dbinfo.ID)
 		if err != nil {
 			return nil, cerror.WrapError(cerror.ErrMetaListDatabases, err)
 		}
-		for _, tableInfo := range tableInfos {
-			if filter.ShouldIgnoreTable(dbinfo.Name.O, tableInfo.Name.O) {
-				log.Debug("ignore table", zap.String("table", tableInfo.Name.O))
+		tableNeeded := make([]*timodel.TableNameInfo, 0, len(tableNames))
+		// filter tables
+		for _, table := range tableNames {
+			if filter.ShouldIgnoreTable(dbinfo.Name.O, table.Name.O) {
+				log.Debug("ignore table", zap.String("table", table.Name.O))
 				continue
 			}
+			tableNeeded = append(tableNeeded, table)
+		}
+		tableInfos := make([]*timodel.TableInfo, 0, len(tableNeeded))
+		for _, table := range tableNeeded {
+			tableInfo, err := meta.GetTable(dbinfo.ID, table.ID)
+			if err != nil {
+				return nil, errors.Trace(err)
+			}
+			tableInfos = append(tableInfos, tableInfo)
+		}
+
+		for _, tableInfo := range tableInfos {
 			tableInfo := model.WrapTableInfo(dbinfo.ID, dbinfo.Name.O, currentTs, tableInfo)
 			snap.inner.tables.ReplaceOrInsert(versionedID{
 				id:     tableInfo.ID,
@@ -193,8 +207,6 @@ func NewSnapshotFromMeta(
 			ineligible := !tableInfo.IsEligible(forceReplicate)
 			if ineligible {
 				snap.inner.ineligibleTables.ReplaceOrInsert(versionedID{id: tableInfo.ID, tag: tag})
-			} else {
-				tables = append(tables, tableInfo)
 			}
 			if pi := tableInfo.GetPartitionInfo(); pi != nil {
 				for _, partition := range pi.Definitions {
@@ -209,15 +221,10 @@ func NewSnapshotFromMeta(
 		}
 	}
 	snap.inner.currentTs = currentTs
-	var sb strings.Builder
-	sb.WriteString(fmt.Sprintf("%d tables to be replicated: ", len(tables)))
-	for _, table := range tables {
-		sb.WriteString(fmt.Sprintf("%s.%s, ", table.TableName.Schema, table.TableName.Table))
-	}
 	log.Info("schema snapshot created",
 		zap.Stringer("changefeed", id),
 		zap.Uint64("currentTs", currentTs),
-		zap.String("tables", sb.String()))
+		zap.Any("duration", time.Since(start).Seconds()))
 	return snap, nil
 }