[rrd-users] rrd resize error

[Tobias Oetiker]

Hi Daniel,
Today Daniel De Marco wrote:

> * Tobias Oetiker <tobi at oetiker.ch> [06/28/2011 18:39]:
> > neat ... so I guess the following should fix this problem:
> >         atoi(rrd->stat_head->version) < 3 ? sizeof(time_t) : sizeof(live_head_t) + \
>
> this crashes badly. I think it's because the plus has higher precedence.

indeed :-)

>
> This seems to work ok:
> --- ../../rrdtool-1.4.5/src/rrd_format.c        2010-12-26 14:24:48.000000000 -0500
> +++ rrd_format.c        2011-06-29 08:35:38.000000000 -0400
> @@ -105,8 +105,7 @@
>      return sizeof(stat_head_t) + \
>          sizeof(ds_def_t) * rrd->stat_head->ds_cnt + \
>          sizeof(rra_def_t) * rrd->stat_head->rra_cnt + \
> -        sizeof(time_t) + \
> -        sizeof(live_head_t) + \
> +       (atoi(rrd->stat_head->version) < 3 ? sizeof(time_t) : sizeof(live_head_t)) + \
>          sizeof(pdp_prep_t) * rrd->stat_head->ds_cnt + \
>          sizeof(cdp_prep_t) * rrd->stat_head->ds_cnt * rrd->stat_head->rra_cnt + \
>          sizeof(rra_ptr_t) * rrd->stat_head->rra_cnt;
>
> However this solves the problem only for new files.
>
> In order to be able to grow or shrink files created with the old version I used the following:
> --- ../../rrdtool-1.4.5/src/rrd_resize.c        2010-12-26 14:24:48.000000000 -0500
> +++ rrd_resize.c        2011-06-29 09:07:14.000000000 -0400
> @@ -262,9 +262,14 @@
>      /* Move the rest of the CDPs
>       */
>      while (1) {
> -        if (rrd_read(rrd_file, &buffer, sizeof(rrd_value_t) * 1) <= 0)
> +        ssize_t b_read;
> +        if ((b_read=rrd_read(rrd_file, &buffer, sizeof(rrd_value_t) * 1)) <= 0)
>              break;
> -        rrd_write(rrd_out_file, &buffer, sizeof(rrd_value_t) * 1);
> +        if(rrd_out_file->pos+b_read > rrd_out_file->file_len) {
> +            fprintf(stderr,"WARNING: ignoring last %zu bytes\nWARNING: if you see this message multiple times for a single file you're in trouble\n", b_read);
> +            continue;
> +        }
> +        rrd_write(rrd_out_file, &buffer, b_read);
>      }
>      rrdnew.rra_def[target_rra].row_cnt += modify;
>      rrd_seek(rrd_out_file,

neat .... thanks
tobi
>
> Daniel.
>
>

-- 
Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland
http://it.oetiker.ch tobi at oetiker.ch ++41 62 775 9902 / sb: -9900