From 8360887741badd6eb69c3dca9125f72de877d87f Mon Sep 17 00:00:00 2001
From: zyguan <zhongyangguan@gmail.com>
Date: Mon, 27 May 2019 14:56:21 +0800
Subject: [PATCH] stability: retry truncating sst files upon failure (#484)

* stability: retry truncating sst files upon failure
---
 tests/failover.go     |  7 ++--
 tests/pkg/ops/tikv.go | 84 ++++++++++++++++++++++++++++---------------
 2 files changed, 61 insertions(+), 30 deletions(-)

diff --git a/tests/failover.go b/tests/failover.go
index 798a37def9..f6ae2544e7 100644
--- a/tests/failover.go
+++ b/tests/failover.go
@@ -7,8 +7,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/pingcap/tidb-operator/tests/slack"
-
 	// To register MySQL driver
 	_ "github.com/go-sql-driver/mysql"
 	"github.com/golang/glog"
@@ -17,6 +15,7 @@ import (
 	"github.com/pingcap/tidb-operator/pkg/label"
 	"github.com/pingcap/tidb-operator/tests/pkg/client"
 	"github.com/pingcap/tidb-operator/tests/pkg/ops"
+	"github.com/pingcap/tidb-operator/tests/slack"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/labels"
@@ -65,6 +64,8 @@ func (oa *operatorActions) TruncateSSTFileThenCheckFailover(info *TidbClusterCon
 	glog.Infof("deleting pod: [%s/%s] and wait 1 minute for the pod to terminate", info.Namespace, store.PodName)
 	err = cli.CoreV1().Pods(info.Namespace).Delete(store.PodName, nil)
 	if err != nil {
+		glog.Errorf("failed to get delete the pod: ns=%s tc=%s pod=%s err=%s",
+			info.Namespace, info.ClusterName, store.PodName, err.Error())
 		return err
 	}
 
@@ -77,6 +78,8 @@ func (oa *operatorActions) TruncateSSTFileThenCheckFailover(info *TidbClusterCon
 		Store:     store.ID,
 	})
 	if err != nil {
+		glog.Errorf("failed to truncate the sst file: ns=%s tc=%s store=%s err=%s",
+			info.Namespace, info.ClusterName, store.ID, err.Error())
 		return err
 	}
 	oa.EmitEvent(info, fmt.Sprintf("TruncateSSTFile: tikv: %s/%s", info.Namespace, store.PodName))
diff --git a/tests/pkg/ops/tikv.go b/tests/pkg/ops/tikv.go
index ddf1da4903..9e399449c3 100644
--- a/tests/pkg/ops/tikv.go
+++ b/tests/pkg/ops/tikv.go
@@ -14,13 +14,21 @@
 package ops
 
 import (
+	"fmt"
+	"strconv"
 	"strings"
+	"time"
 
 	"github.com/golang/glog"
 	"github.com/pingcap/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
+const (
+	retryLimit            = 15
+	maxSSTFilesToTruncate = 20
+)
+
 type TruncateOptions struct {
 	Namespace string
 	Cluster   string
@@ -32,7 +40,7 @@ type TiKVOps struct {
 }
 
 func (ops *TiKVOps) TruncateSSTFile(opts TruncateOptions) error {
-	glog.Infof("truncate sst option: %+v", opts)
+	logHdr := fmt.Sprintf("store: %s cluster: [%s/%s] ", opts.Store, opts.Namespace, opts.Cluster)
 
 	tc, err := ops.PingcapV1alpha1().TidbClusters(opts.Namespace).Get(opts.Cluster, metav1.GetOptions{})
 	if err != nil {
@@ -54,41 +62,61 @@ func (ops *TiKVOps) TruncateSSTFile(opts TruncateOptions) error {
 		})
 	}
 
-	stdout, stderr, err := exec("find", "/var/lib/tikv/db", "-name", "*.sst", "-o", "-name", "*.save")
-	if err != nil {
-		glog.Errorf("list sst files: stderr=%s err=%s", stderr, err.Error())
-		return errors.Annotate(err, "list sst files")
-	}
+	retryCount := 0
+	for ; retryCount < retryLimit; retryCount++ {
+		if retryCount > 0 {
+			time.Sleep(10 * time.Second)
+		}
+		stdout, stderr, err := exec("find", "/var/lib/tikv/db", "-name", "*.sst", "-o", "-name", "*.save")
+		if err != nil {
+			glog.Warningf(logHdr+"list sst files: stderr=%s err=%s", stderr, err.Error())
+			continue
+		}
 
-	sstCandidates := make(map[string]bool)
+		sstCandidates := make(map[string]bool)
 
-	for _, f := range strings.Split(stdout, "\n") {
-		f = strings.TrimSpace(f)
-		if len(f) > 0 {
-			sstCandidates[f] = true
+		for _, f := range strings.Split(stdout, "\n") {
+			f = strings.TrimSpace(f)
+			if len(f) > 0 {
+				sstCandidates[f] = true
+			}
 		}
-	}
 
-	sst := ""
-	for k := range sstCandidates {
-		if strings.HasSuffix(k, ".sst") && !sstCandidates[k+".save"] {
-			sst = k
+		ssts := make([]string, 0, maxSSTFilesToTruncate)
+		for k := range sstCandidates {
+			if len(ssts) >= maxSSTFilesToTruncate {
+				break
+			}
+			if strings.HasSuffix(k, ".sst") && !sstCandidates[k+".save"] {
+				ssts = append(ssts, k)
+			}
+		}
+		if len(ssts) == 0 {
+			glog.Warning(logHdr + "cannot find a sst file")
+			continue
 		}
-	}
-	if len(sst) == 0 {
-		return errors.New("cannot find a sst file")
-	}
 
-	_, stderr, err = exec("cp", sst, sst+".save")
-	if err != nil {
-		glog.Errorf("backup sst file: stderr=%s err=%s", stderr, err.Error())
-		return errors.Annotate(err, "backup sst file")
+		truncated := 0
+		for _, sst := range ssts {
+			_, stderr, err = exec("sh", "-c",
+				fmt.Sprintf("cp %s %s.save && truncate -s 0 %s", sst, sst, sst))
+			if err != nil {
+				glog.Warningf(logHdr+"truncate sst file: sst=%s stderr=%s err=%s", sst, stderr, err.Error())
+				continue
+			}
+			truncated++
+		}
+		if truncated == 0 {
+			glog.Warningf(logHdr + "no sst file has been truncated")
+			continue
+		}
+
+		glog.Infof(logHdr+"%d sst files got truncated", truncated)
+		break
 	}
 
-	_, stderr, err = exec("truncate", "-s", "0", sst)
-	if err != nil {
-		glog.Errorf("truncate sst file: stderr=%s err=%s", stderr, err.Error())
-		return errors.Annotate(err, "truncate sst file")
+	if retryCount == retryLimit {
+		return errors.New("failed to truncate sst file after " + strconv.Itoa(retryLimit) + " trials")
 	}
 
 	return nil