Merge pull request #1084 from percona/PBM-14780-pbm-backup-does-not-work-with-single-cpu

PBM-14780 Adjust concurrentCollections for backup operation for single CPU

Author: radoslawszulgo

cmd/pbm-agent/main.go

@@ -101,7 +101,7 @@ func setRootFlags(rootCmd *cobra.Command) {
 	rootCmd.Flags().Int("dump-parallel-collections", 0, "Number of collections to dump in parallel")
 	_ = viper.BindPFlag("backup.dump-parallel-collections", rootCmd.Flags().Lookup("dump-parallel-collections"))
 	_ = viper.BindEnv("backup.dump-parallel-collections", "PBM_DUMP_PARALLEL_COLLECTIONS")
-	viper.SetDefault("backup.dump-parallel-collections", runtime.NumCPU()/2)
+	viper.SetDefault("backup.dump-parallel-collections", max(runtime.NumCPU()/2, 1))
 
 	rootCmd.Flags().String("log-path", "", "Path to file")
 	_ = viper.BindPFlag("log.path", rootCmd.Flags().Lookup("log-path"))

pbm/archive/backup.go

@@ -105,7 +105,7 @@ func NewBackup(ctx context.Context, options BackupOptions) (*backupImpl, error)
 		newFile:     options.NewFile,
 		nsFilter:    DefaultNSFilter,
 		docFilter:   DefaultDocFilter,
-		concurrency: runtime.NumCPU() / 2,
+		concurrency: max(runtime.NumCPU()/2, 1),
 	}
 
 	if options.NSFilter != nil {

pbm/archive/conv.go

@@ -62,7 +62,7 @@ func GenerateV1FromV2(ctx context.Context, stg storage.Storage, bcp, rs string)
 func convertMetaToV1(metaV2 *ArchiveMetaV2) (*archiveMeta, error) {
 	metaV1 := &archiveMeta{
 		Header: &mtArchive.Header{
-			ConcurrentCollections: int32(runtime.NumCPU() / 2),
+			ConcurrentCollections: int32(max(runtime.NumCPU()/2, 1)),
 
 			FormatVersion: "0.1",
 			ServerVersion: metaV2.ServerVersion,