*** a/src/backend/optimizer/path/costsize.c
--- b/src/backend/optimizer/path/costsize.c
***************
*** 4145,4151 **** set_default_effective_cache_size(void)
  		effective_cache_size = 0;
  		/* and let check_effective_cache_size() compute the setting */
  		SetConfigOption("effective_cache_size", "-1",
! 						PGC_POSTMASTER, PGC_S_OVERRIDE);
  	}
  	Assert(effective_cache_size > 0);
  }
--- 4145,4151 ----
  		effective_cache_size = 0;
  		/* and let check_effective_cache_size() compute the setting */
  		SetConfigOption("effective_cache_size", "-1",
! 						PGC_POSTMASTER, PGC_S_FILE);
  	}
  	Assert(effective_cache_size > 0);
  }