Re: Showing index details with \d on psql - Mailing list pgsql-patches

>> I don't like the '*' things.  They look ugly and convey little
>> real information.

> They convey "this column is indexed" and also indicate in how many
> indexes it appears.

I tend to agree with Peter on that part ... the asterisks add more
clutter than information.  I also think that they could lead to
ambiguity; for example, it's not obvious that the * is not part of
the default clause where there's a default.

I have a large number of problems with this part of your patch:

              char   *s = _("Indexes:");

!             snprintf(buf, sizeof(buf), "%*s %s%s%s",
!                      (int)strlen(s),
!                      i == 0 ? s : "",
!                      PQgetvalue(result1, i, 0),
!                      strcmp(PQgetvalue(result1, i, 2), "t") == 0 ? _(" (primary key)") : "",
!                      strcmp(PQgetvalue(result1, i, 3), "t") == 0 ? _(" (unique)") : "");
!
!             char indexchar[5]; /* Should be plenty */
!             int indexnumber=0;
!             char * indexlist = PQgetvalue(result1, i, 1);
!             int j,found;
!             for (j=0,found=0;j<=strlen(indexlist); j++) {
!               if (indexlist[j] == 0 || indexlist[j] == 32) {
!                 indexnumber = atoi(indexchar);
!                 if (indexnumber>0) /* pg_class has a -2! */
!                   {
!                   strcat(cells[(indexnumber-1) * cols + 2],
!                          cells[(indexnumber-1) * cols +2][0] ? " *" : "*");
!                   strcat(buf, ++found==1 ? " (" : ", ");
!                   strcat(buf, cells[(indexnumber-1) * cols]);
!                   }
!                 indexchar[0] = '\0';
!                 }
!               else { strcat(indexchar,&indexlist[j]); }
!             }
!             if (found) /* must cover for pg_class again */
!               strcat(buf, ")");
              footers[count_footers++] = xstrdup(buf);

Gripe #1: declarations after the start of a block are a C++-ism.  They
are not legal in ANSI C.

Gripe #2: what is indexchar[], why is it being used without
initialization, and what is your justification for thinking 5 is enough
space?

Gripe #3: "32" is not a portable spelling of "' '".

Gripe #4: looks to me like it will fail when indexes are on columns
numbered 10 or above, because the loop will do strcat() multiple times.

Gripe #5: doing the wrong thing on indexes that mention system columns
(negative column numbers) isn't acceptable.

You are really doing things quite the hard way here anyhow, since
pg_get_indexdef would produce the info you want without so much work,
and with less dependency in psql on backend catalog details.  I'd
suggest pulling the pg_get_indexdef result instead of indkey in the
SELECT, and then just print the part after USING.

BTW, "primary key" implies "unique", so I think it's not necessary to
print both annotations for a primary key.

            regards, tom lane