Re: semi-variable length type - Mailing list pgsql-general

From Tom Lane
Subject Re: semi-variable length type
Date
Msg-id 31967.1392993647@sss.pgh.pa.us
Whole thread Raw
In response to Re: semi-variable length type  (James Harper <james.harper@bendigoit.com.au>)
List pgsql-general
James Harper <james.harper@bendigoit.com.au> writes:
>> regression=# create table t1 (f1 float(5), f2 float(30));
>> CREATE TABLE
>> regression=# \d t1
>> Table "public.t1"
>> Column |       Type       | Modifiers
>> --------+------------------+-----------
>> f1     | real             |
>> f2     | double precision |
>>
>> Other than the fact that we don't remember whether you asked for 5 bits
>> or 24, I think this meets the spec requirements.

> Is the 4 byte or 8 byte decision based on (n) implemented in the parser? I can't see a 'float' type in pg_type.

Yeah, gram.y is hard-wired to produce either "float4" or "float8" from
float(N) (see the opt_float production).

Ordinarily I'd think that that was a pretty sucky implementation
technique, but since this is implementing behavior called for in
the SQL standard, it's probably not worth trying to make it
any more flexible.

            regards, tom lane


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