From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id ECCFC24566 for ; Mon, 22 Jul 2019 06:20:26 -0400 (EDT) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing.freelists.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id iR1MOs-5hgrX for ; Mon, 22 Jul 2019 06:20:26 -0400 (EDT) Received: from smtpng3.m.smailru.net (smtpng3.m.smailru.net [94.100.177.149]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTPS id 48E502455B for ; Mon, 22 Jul 2019 06:20:17 -0400 (EDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.11\)) Subject: [tarantool-patches] Re: [PATCH 6/6] sql: allow to specify UNSIGNED column type From: "n.pettik" In-Reply-To: <989f9710-043f-447a-0cc4-76eb317bc1e9@tarantool.org> Date: Mon, 22 Jul 2019 13:20:14 +0300 Content-Transfer-Encoding: quoted-printable Message-Id: References: <734EC309-6DCF-42C2-8041-135A8B68E935@tarantool.org> <9a397d31-1cae-0dd0-cdd6-733388cb01af@tarantool.org> <552F96C1-DAC5-4F18-9F5A-BF50C6BBC205@tarantool.org> <8e4feefd-7bfb-18af-fd0f-b45384e5d2ef@tarantool.org> <127420CE-540E-439C-B2BD-20007EE98328@tarantool.org> <989f9710-043f-447a-0cc4-76eb317bc1e9@tarantool.org> Sender: tarantool-patches-bounce@freelists.org Errors-to: tarantool-patches-bounce@freelists.org Reply-To: tarantool-patches@freelists.org List-Help: List-Unsubscribe: List-software: Ecartis version 1.0.0 List-Id: tarantool-patches List-Subscribe: List-Owner: List-post: List-Archive: To: tarantool-patches@freelists.org Cc: Vladislav Shpilevoy > On 19 Jul 2019, at 00:08, Vladislav Shpilevoy = wrote: > On 18/07/2019 22:56, n.pettik wrote: >>=20 >>> On 18 Jul 2019, at 23:18, Vladislav Shpilevoy = > wrote: >>>>> ------------------------- >>>>> vdbe.c:307 >>>>>=20 >>>>>> case FIELD_TYPE_INTEGER: >>>>>> case FIELD_TYPE_UNSIGNED: >>>>>> if ((record->flags & MEM_Int) =3D=3D MEM_Int) >>>>>> return 0; >>>>>> if ((record->flags & MEM_UInt) =3D=3D MEM_UInt) >>>>>> return 0; >>>>>> if ((record->flags & MEM_Real) =3D=3D MEM_Real) { >>>>>> int64_t i =3D (int64_t) record->u.r; >>>>>> if (i =3D=3D record->u.r) >>>>>> mem_set_int(record, record->u.r, >>>>>> record->u.r <=3D -1); >>>>>> return 0; >>>>>> } >>>>>=20 >>>>> It is a part of function mem_apply_type. When target type is >>>>> UNSIGNED, and a value is MEM_Int, you do nothing. Why? Looks like >>>>> it is possible to pass here a negative value, and CAST UNSIGNED >>>>> would do nothing. >>>>=20 >>>> Basically, this function implements sort of implicit cast >>>> which takes place before comparison/assignment. >>>> For comparisons it makes no sense - we can compare >>>> integer with unsigned value - the latter is always greater. >>>> For assignment it is also meaningless: if we attempt >>>> at inserting negative values to unsigned field appropriate >>>> error will be raised anyway. If you can come up with >>>> specific example, let=E2=80=99s discuss it. >>>>=20 >>>=20 >>> I can't provide a test. But the function is named mem_apply_type, >>> and it doesn't apply type, when it is unsigned, and a value is >>> negative. Doesn't it look wrong to you? >>>=20 >>> If some code wants to get an integer, it can apply = FIELD_TYPE_INTEGER >>> instead of FIELD_TYPE_UNSIGNED. IMO, an attempt to apply unsigned >>> to int should raise an error here. Otherwise this function can't >>> be named 'apply_type' because it ignores negative -> unsigned case. >>=20 >> Okay, let=E2=80=99s rename it. I can suggest these options: >>=20 >> mem_cast_implicit() >> mem_cast_implicit_to_type() >> mem_implicit_cast_to_type() >> mem_convert_implicit() >> mem_convert_to_type() >> mem_type_coerce_implicit() >> mem_type_implicit_coercion() >> mem_type_coercion_implicit() >> mem_implicit_type_juggling() >> mem_implicit_juggle_to_type() >> mem_do_implicit_conversion() >> mem_do_implicit_coercion() >>=20 >> Or any other combination :) >>=20 >=20 > But it is not implicit. It just does not work, when a value is = negative, > and type is unsigned. So, you want to see smth like this: diff --git a/src/box/sql/vdbe.c b/src/box/sql/vdbe.c index 73a1f321b..835544d44 100644 --- a/src/box/sql/vdbe.c +++ b/src/box/sql/vdbe.c @@ -306,8 +306,6 @@ mem_apply_type(struct Mem *record, enum field_type = type) switch (type) { case FIELD_TYPE_INTEGER: case FIELD_TYPE_UNSIGNED: - if ((record->flags & MEM_Int) =3D=3D MEM_Int) - return 0; if ((record->flags & MEM_UInt) =3D=3D MEM_UInt) return 0; if ((record->flags & MEM_Real) =3D=3D MEM_Real) { @@ -317,7 +315,14 @@ mem_apply_type(struct Mem *record, enum field_type = type) record->u.r <=3D -1); return 0; } - return sqlVdbeMemIntegerify(record, false); + if (sqlVdbeMemIntegerify(record, false) !=3D 0) + return -1; + if ((record->flags & MEM_Int) =3D=3D MEM_Int) { + if (type =3D=3D FIELD_TYPE_UNSIGNED) + return -1; + return 0; + } + return 0; The difference can be seen in queries like this: box.execute("CREATE TABLE t1 (id UNSIGNED PRIMARY KEY);") box.execute("INSERT INTO t1 VALUES (-3);") --- - error: 'Type mismatch: can not convert -3 to unsigned' =E2=80=A6 Without this change we got: 'Tuple field 1 type does not match one required by operation: expected = unsigned=E2=80=99 I consider this check to be a bit inappropriate since It is redundant. Comparison between unsigned and signed is well defined; insertion to the unsigned field is prohibited and checked in more low level core mechanisms. I would say I don=E2=80=99t mind applying = this change (and already applied to speed up review process), but on the other side I don=E2=80=99t understand why do we need to add extra = checks on top (SQL) layer.