Re: BUG #15668: Server crash in transformPartitionRangeBounds

On 2019/03/13 1:35, Tom Lane wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>> On Mon, Mar 11, 2019 at 2:45 AM Amit Langote
>> <Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> wrote:
>>> I noticed another issue with the code -- it's using strcmp() to compare
>>> specified string against "minvalue" and "maxvalue", which causes the
>>> following silly error:
>>>
>>> create table q2 partition of q for values from ("MINVALUE") to (maxvalue);
>>> ERROR: column "MINVALUE" does not exist
>>> LINE 1: create table q2 partition of q for values from ("MINVALUE") ...
>>>
>>> It should be using pg_strncasecmp().
>
>> Uh, why? Generally, an unquoted keyword is equivalent to a quoted
>> lowercase version of that same keyword, not anything else. Like
>> CREATE TABLE "foo" = CREATE TABLE FOO <> CREATE TABLE "FOO".

OK. Perhaps, I reacted too strongly to encountering the following
behavior with HEAD:

create table p1 partition of p for values from ("minValue") to (1);
ERROR: column "minValue" does not exist

but,

create table p1 partition of p for values from ("minvalue") to (1);
\d p1
Table "public.p1"
Column │ Type │ Collation │ Nullable │ Default
────────┼─────────┼───────────┼──────────┼─────────
a │ integer │ │ │
Partition of: p FOR VALUES FROM (MINVALUE) TO (1)

But as you and Tom have pointed out, maybe it's normal.

> Yeah. The behavior shown above is entirely correct, and accepting the
> statement would be flat out wrong; it would cause trouble if somebody
> created a table containing multiple case-variations of MINVALUE.

Sorry, I didn't understand this last part. Different case-variations will
all be interpreted as a minvalue (negative infinity) range bound and
flagged if the resulting range bound constraint would be invalid.

Did you mean something like the following:

create table p1 partition of ... from ("minValue") to ("MINVALUE");

which using pg_strncasecmp() comparisons gives:

create table p1 partition of p for values from ("minValue") to ("MINVALUE");
ERROR: empty range bound specified for partition "p1"
DETAIL: Specified lower bound (MINVALUE) is greater than or equal to
upper bound (MINVALUE).

which is same as the behavior with unquoted keyword syntax:

create table p1 partition of p for values from (minValue) to (MINVALUE);
ERROR: empty range bound specified for partition "p1"
DETAIL: Specified lower bound (MINVALUE) is greater than or equal to
upper bound (MINVALUE).

whereas quoted identifier syntax on HEAD gives:

create table p1 partition of p for values from ("minValue") to ("MINVALUE");
ERROR: column "minValue" does not exist
LINE 1: create table p1 partition of p for values from ("minValue") ...

However, as you guys said, HEAD is behaving sanely.

Thanks,
Amit