*** a/doc/src/sgml/ref/pg_basebackup.sgml
--- b/doc/src/sgml/ref/pg_basebackup.sgml
***************
*** 364,370 **** PostgreSQL documentation
        <listitem>
         <para>
          Enables gzip compression of tar file output, and specifies the
!         compression level (1 through 9, 9 being best
          compression). Compression is only available when using the tar
          format.
         </para>
--- 364,370 ----
        <listitem>
         <para>
          Enables gzip compression of tar file output, and specifies the
!         compression level (0 through 9, 0 being no compression and 9 being best
          compression). Compression is only available when using the tar
          format.
         </para>
*** a/src/bin/pg_basebackup/pg_basebackup.c
--- b/src/bin/pg_basebackup/pg_basebackup.c
***************
*** 2073,2079 **** main(int argc, char **argv)
  				break;
  			case 'Z':
  				compresslevel = atoi(optarg);
! 				if (compresslevel <= 0 || compresslevel > 9)
  				{
  					fprintf(stderr, _("%s: invalid compression level \"%s\"\n"),
  							progname, optarg);
--- 2073,2079 ----
  				break;
  			case 'Z':
  				compresslevel = atoi(optarg);
! 				if (compresslevel < 0 || compresslevel > 9)
  				{
  					fprintf(stderr, _("%s: invalid compression level \"%s\"\n"),
  							progname, optarg);