[Tarantool-patches] [PATCH v2 1/1] sql: limit blob size during CAST AS INTEGER
Nikita Pettik
korablev at tarantool.org
Thu Feb 20 22:58:21 MSK 2020
On 13 Feb 11:16, imeevma at tarantool.org wrote:
> >> +test:do_execsql_test(
> >> + "cast-6.1",
> >> + [[
> >> + CREATE TABLE t (a VARBINARY PRIMARY KEY);
> >> + INSERT INTO t VALUES (X'33'), (X'372020202020');
> >> + SELECT a, CAST(a AS NUMBER), CAST(a AS INTEGER), CAST(a AS UNSIGNED) FROM t;
> >> + DROP TABLE t;
> >> + ]], {
> >> + -- <cast-6.1>
> >> + '3', 3, 3, 3, '7 ', 7, 7, 7
> >> + -- </cast-6.1>
> >> + })
> >> +
> >> +test:do_execsql_test(
> >> + "cast-6.2",
> >> + [[
> >> + CREATE TABLE t (a VARBINARY PRIMARY KEY, i INT);
> >> + INSERT INTO t VALUES (X'33', 1);
> >> + SELECT a, CAST(a AS NUMBER), CAST(a AS INTEGER), CAST(a AS UNSIGNED) FROM t;
> >> + DROP TABLE t;
> >
> > What's the (in functional sense) difference between 6.1 and 6.2?
> >
> True, in this test it isn't obvious what it should show. I fixed
> the test. I made this test to show that the '\0' at the end of the
> BLOB is important. One possible way to solve this problem was to
> limit the length of the decoded BLOB (without copying and adding
> '\0'), but this could lead to an incorrect result of this test.
> I mean this:
>
> tarantool> CREATE TABLE t (a VARBINARY PRIMARY KEY, i INT) WITH ENGINE = 'vinyl';
> ---
> - row_count: 1
> ...
>
> tarantool> INSERT INTO t VALUES (X'33', 0x33);
> ---
> - row_count: 1
> ...
So now you insert 0x33 instead of 1 to integer field. But how does it
affect test? I failed to understand. In both cases you fetch and operate
on blob, meanwhile integer field doesn't seem to be involved.
>
> tarantool> SELECT a, CAST(a AS NUMBER), CAST(a AS INTEGER), CAST(a AS UNSIGNED) FROM t;
> ---
> - metadata:
> - name: A
> type: varbinary
> - name: CAST(a AS NUMBER)
> type: number
> - name: CAST(a AS INTEGER)
> type: integer
> - name: CAST(a AS UNSIGNED)
> type: unsigned
> rows:
> - ['3', 33, 33, 33]
> ...
>
> +--
> +-- In some cases, the absence of '\0' could lead to an incorrect
> +-- result. Make sure this does not happen now.
> +--
> test:do_execsql_test(
> "cast-6.2",
> [[
> CREATE TABLE t (a VARBINARY PRIMARY KEY, i INT);
> - INSERT INTO t VALUES (X'33', 1);
> + INSERT INTO t VALUES (X'33', 0x33);
> SELECT a, CAST(a AS NUMBER), CAST(a AS INTEGER), CAST(a AS UNSIGNED) FROM t;
> DROP TABLE t;
> ]], {
>
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