Re: Selecting a constant question

"Dann Corbit" <DCorbit(at)connx(dot)com> writes:
> The issue is this:
> Postgres describes the column with a typmod of -1 (unknown) and a length
> of 65534.

Oh, you're looking at typlen not typmod. Please observe the comments in
pg_type.h:

/*
* For a fixed-size type, typlen is the number of bytes we use to
* represent a value of this type, e.g. 4 for an int4. But for a
* variable-length type, typlen is negative. We use -1 to indicate a
* "varlena" type (one that has a length word), -2 to indicate a
* null-terminated C string.
*/
int2 typlen;

You should be treating typlen as signed not unsigned, and not assuming a
fixed width for any negative value.

Since the width refers to the server internal representation, and not to
what comes down the wire, I find it pretty strange for an application to
be using typlen for anything at all actually.

regards, tom lane