Re: stawidth inconsistency with all NULL columns - Mailing list pgsql-hackers

Joe Conway <mail@joeconway.com> writes:
> else if (null_cnt > 0)
> {
>     /* We found only nulls; assume the column is entirely null */
>     stats->stats_valid = true;
>     stats->stanullfrac = 1.0;
>     if (is_varwidth)
>         stats->stawidth = 0;    /* "unknown" */
>     else
>         stats->stawidth = stats->attrtype->typlen;
>     stats->stadistinct = 0.0;       /* "unknown" */
> }
> 8<-----------------

> So apparently intentional, but seems gratuitously inconsistent. Could
> this cause any actual inconsistent behaviors? In any case that first
> comment does not reflect the code.

Are you suggesting that we should set stawidth to zero even for a
fixed-width datatype?  That seems pretty silly.  We know exactly what
the value should be, and would be if we'd chanced to find even one
non-null entry.

            regards, tom lane