fix: because lock is not release, drop cutover sentry table is hanged

Author: lmtwga

go/logic/applier.go

@@ -9,7 +9,6 @@ import (
 	gosql "database/sql"
 	"fmt"
 	"strings"
-	"sync"
 	"sync/atomic"
 	"time"
 
@@ -904,7 +903,7 @@ func (this *Applier) CreateAtomicCutOverSentryTable() error {
 }
 
 // AtomicCutOverMagicLock
-func (this *Applier) AtomicCutOverMagicLock(sessionIdChan chan int64, tableLocked chan<- error, okToUnlockTable <-chan bool, tableUnlocked chan<- error, dropCutOverSentryTableOnce *sync.Once) error {
+func (this *Applier) AtomicCutOverMagicLock(sessionIdChan chan int64, tableLocked chan<- error, okToUnlockTable <-chan bool, tableUnlocked chan<- error) error {
 	tx, err := this.db.Begin()
 	if err != nil {
 		tableLocked <- err
@@ -915,6 +914,7 @@ func (this *Applier) AtomicCutOverMagicLock(sessionIdChan chan int64, tableLocke
 		tableLocked <- fmt.Errorf("Unexpected error in AtomicCutOverMagicLock(), injected to release blocking channel reads")
 		tableUnlocked <- fmt.Errorf("Unexpected error in AtomicCutOverMagicLock(), injected to release blocking channel reads")
 		tx.Rollback()
+		this.DropAtomicCutOverSentryTableIfExists()
 	}()
 
 	var sessionId int64
@@ -983,12 +983,10 @@ func (this *Applier) AtomicCutOverMagicLock(sessionIdChan chan int64, tableLocke
 		sql.EscapeName(this.migrationContext.GetOldTableName()),
 	)
 
-	dropCutOverSentryTableOnce.Do(func() {
-		if _, err := tx.Exec(query); err != nil {
-			this.migrationContext.Log.Errore(err)
-			// We DO NOT return here because we must `UNLOCK TABLES`!
-		}
-	})
+	if _, err := tx.Exec(query); err != nil {
+		this.migrationContext.Log.Errore(err)
+		// We DO NOT return here because we must `UNLOCK TABLES`!
+	}
 
 	// Tables still locked
 	this.migrationContext.Log.Infof("Releasing lock from %s.%s, %s.%s",

go/logic/migrator.go

@@ -13,7 +13,6 @@ import (
 	"math"
 	"os"
 	"strings"
-	"sync"
 	"sync/atomic"
 	"time"
 
@@ -639,12 +638,8 @@ func (this *Migrator) atomicCutOver() (err error) {
 	defer atomic.StoreInt64(&this.migrationContext.InCutOverCriticalSectionFlag, 0)
 
 	okToUnlockTable := make(chan bool, 4)
-	var dropCutOverSentryTableOnce sync.Once
 	defer func() {
 		okToUnlockTable <- true
-		dropCutOverSentryTableOnce.Do(func() {
-			this.applier.DropAtomicCutOverSentryTableIfExists()
-		})
 	}()
 
 	atomic.StoreInt64(&this.migrationContext.AllEventsUpToLockProcessedInjectedFlag, 0)
@@ -653,7 +648,7 @@ func (this *Migrator) atomicCutOver() (err error) {
 	tableLocked := make(chan error, 2)
 	tableUnlocked := make(chan error, 2)
 	go func() {
-		if err := this.applier.AtomicCutOverMagicLock(lockOriginalSessionIdChan, tableLocked, okToUnlockTable, tableUnlocked, &dropCutOverSentryTableOnce); err != nil {
+		if err := this.applier.AtomicCutOverMagicLock(lockOriginalSessionIdChan, tableLocked, okToUnlockTable, tableUnlocked); err != nil {
 			this.migrationContext.Log.Errore(err)
 		}
 	}()