restore: fix gc life time not recovered after table restore

lightning/restore/restore.go

@@ -79,6 +79,8 @@ var (
 // DeliverPauser is a shared pauser to pause progress to (*chunkRestore).encodeLoop
 var DeliverPauser = common.NewPauser()
 
+var gcLifeTimeKey struct{}
+
 func init() {
 	cfg := tidbcfg.GetGlobalConfig()
 	cfg.Log.SlowThreshold = 3000
@@ -490,12 +492,17 @@ func (rc *RestoreController) restoreTables(ctx context.Context) error {
 	}
 	taskCh := make(chan task, rc.cfg.App.IndexConcurrency)
 	defer close(taskCh)
+	oriGCLifeTime, err := ObtainGCLifeTime(ctx, rc.tidbMgr.db)
+	if err != nil {
+		return err
+	}
+	ctx2 := context.WithValue(ctx, &gcLifeTimeKey, oriGCLifeTime)
 	for i := 0; i < rc.cfg.App.IndexConcurrency; i++ {
 		go func() {
 			for task := range taskCh {
 				tableLogTask := task.tr.logger.Begin(zap.InfoLevel, "restore table")
 				web.BroadcastTableCheckpoint(task.tr.tableName, task.cp)
-				err := task.tr.restoreTable(ctx, rc, task.cp)
+				err := task.tr.restoreTable(ctx2, rc, task.cp)
 				tableLogTask.End(zap.ErrorLevel, err)
 				web.BroadcastError(task.tr.tableName, err)
 				metric.RecordTableCount("completed", err)
@@ -541,7 +548,7 @@ func (rc *RestoreController) restoreTables(ctx context.Context) error {
 	wg.Wait()
 	stopPeriodicActions <- struct{}{}
 
-	err := restoreErr.Get()
+	err = restoreErr.Get()
 	logTask.End(zap.ErrorLevel, err)
 	return err
 }
@@ -1366,9 +1373,15 @@ func DoChecksum(ctx context.Context, db *sql.DB, table string) (*RemoteChecksum,
 func increaseGCLifeTime(ctx context.Context, db *sql.DB) (oriGCLifeTime string, err error) {
 	// checksum command usually takes a long time to execute,
 	// so here need to increase the gcLifeTime for single transaction.
-	oriGCLifeTime, err = ObtainGCLifeTime(ctx, db)
-	if err != nil {
-		return "", errors.Trace(err)
+	// try to get gcLifeTime from context first.
+	gcLifeTime, ok := ctx.Value(&gcLifeTimeKey).(string)
+	if !ok {
+		oriGCLifeTime, err = ObtainGCLifeTime(ctx, db)
+		if err != nil {
+			return "", err
+		}
+	} else {
+		oriGCLifeTime = gcLifeTime
 	}
 
 	var increaseGCLifeTime bool
@@ -1391,6 +1404,8 @@ func increaseGCLifeTime(ctx context.Context, db *sql.DB) (oriGCLifeTime string,
 		}
 	}
 
+	failpoint.Inject("IncreaseGCUpdateDuration", nil)
+
 	return oriGCLifeTime, nil
 }
 

tests/concurrent-restore/config.toml

@@ -0,0 +1,23 @@
+[lightning]
+table-concurrency = 4
+index-concurrency = 4
+check-requirements = false
+file = "/tmp/lightning_test_result/lightning.log"
+level = "info"
+
+[tikv-importer]
+addr = "127.0.0.1:8808"
+
+[mydumper]
+data-source-dir = "/tmp/lightning_test_result/restore_conc.mydump"
+
+[tidb]
+host = "127.0.0.1"
+user = "root"
+status-port = 10080
+log-level = "error"
+
+[post-restore]
+checksum = true
+compact = false
+analyze = false

tests/concurrent-restore/run.sh

@@ -0,0 +1,48 @@
+#!/bin/sh
+#
+# Copyright 2019 PingCAP, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -eu
+
+# Populate the mydumper source
+DBPATH="$TEST_DIR/restore_conc.mydump"
+TABLE_COUNT=8
+
+mkdir -p $DBPATH
+echo 'CREATE DATABASE restore_conc;' > "$DBPATH/restore_conc-schema-create.sql"
+for i in $(seq "$TABLE_COUNT"); do
+    echo "CREATE TABLE tbl$i(i TINYINT);" > "$DBPATH/restore_conc.tbl$i-schema.sql"
+    echo "INSERT INTO tbl$i VALUES (1);" > "$DBPATH/restore_conc.tbl$i.sql"
+done
+
+run_sql 'select VARIABLE_VALUE from mysql.tidb where VARIABLE_NAME = "tikv_gc_life_time"';
+ORIGINAL_TIKV_GC_LIFE_TIME=$(tail -n 1 "$TEST_DIR/sql_res.$TEST_NAME.txt" | awk '{print $(NF)}')
+
+# add a delay after increasing tikv_gc_life_time, in order to increase confilct possibility
+export GO_FAILPOINTS='github.com/pingcap/tidb-lightning/lightning/restore/IncreaseGCUpdateDuration=sleep(200)'
+
+# Start importing
+run_sql 'DROP DATABASE IF EXISTS restore_conc'
+run_lightning
+echo "Import finished"
+
+# Verify all data are imported
+for i in $(seq "$TABLE_COUNT"); do
+    run_sql "SELECT sum(i) FROM restore_conc.tbl$i;"
+    check_contains 'sum(i): 1'
+done
+
+# check tikv_gc_life_time is recovered to the original value
+run_sql 'select VARIABLE_VALUE from mysql.tidb where VARIABLE_NAME = "tikv_gc_life_time"';
+check_contains "VARIABLE_VALUE: $ORIGINAL_TIKV_GC_LIFE_TIME"