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Message #11811
Re: Please review a patch for MDEV-19284 and MDEV-19285 (instant ALTER)
Hi.
23.04.2019, 16:49, "Alexander Barkov" <bar@xxxxxxxxxxx>:
> Hi,
>
> It seems I forgot to record the rdiff file.
>
> On 4/23/19 4:55 PM, Eugene Kosov wrote:
>> Hello, Marko, Alexander.
>>
>> 23.04.2019, 15:37, "Marko Mäkelä" <marko.makela@xxxxxxxxxxx>:
>>> Bar, thank you for the revision.
>>>
>>> I ran all tests and found a regression for ROW_FORMAT=REDUNDANT, in
>>> the test innodb.instant_alter_charset,redundant. We should allow any
>>> extension of VARCHAR maximum length (in bytes) for
>>> ROW_FORMAT=REDUNDANT. The test attempts to enlarge the column from
>>> 50*3 to 200*3 bytes. That cannot work for other ROW_FORMAT in InnoDB,
>>> but it does for ROW_FORMAT=REDUNDANT.
>>
>> I think it's mostly broken test rather a code regression.
>>
>> Now there is only one case when field length can be increased due to charset change
>> and it's utf8mb3 -> utf8mb4.
>>
>> I think the only test case we need now is CHAR(70) UTF8MB3 -> CHAR(70) UTF8MB4
>> It should work only fro ROW_FORMAT=REDUNDANT
>
> Please find an incremental patch fixing tests.
>
> It adds the block suggested by Eugene and updates the rdiff file
> accordingly.
I think you can remove an old boudary_255 table completely as it's redundant now.
>
> Thanks.
>
>>> Also, please check the spelling once more. I found "Uncode-1.1" in a comment.
>>>
>>> See also the Description of MDEV-18584. I’d want to allow a few more
>>> instantaneous conversion of CHAR columns in InnoDB.
>>> I agree that the (table->file->ha_table_flags() &
>>> HA_EXTENDED_TYPES_CONVERSION) is a bit ugly and could be replaced with
>>> something more descriptive.
>>>
>>> Marko
>>>
>>> On Fri, Apr 19, 2019 at 2:24 PM Alexander Barkov <bar@xxxxxxxxxxx> wrote:
>>>> Hi Marko, Eugene,
>>>>
>>>> Thanks for good suggestions. A new version is attached.
>>>>
>>>> See details inline:
>>>>
>>>> On 4/19/19 2:46 PM, Marko Mäkelä wrote:
>>>> > Hi Bar,
>>>> >
>>>> > I see that these bugs were based on wrong assumptions that ASCII or
>>>> > UCS2 columns would only contain valid ASCII or UTF-16 data. We should
>>>> > have tested these assumptions during the development of MDEV-15564.
>>>> > Luckily these were found before the GA release of MariaDB 10.4.
>>>>
>>>> That was my fault. When we had discussions on this topic with
>>>> Eugene, I overlooked these problems. Sorry for this.
>>>>
>>>> >
>>>> > Here is just a quick note before I will return to work on Tuesday.
>>>> >
>>>> > Please remove ,algorithm=copy from tests. Instead, use
>>>> > --enable_info
>>>> > alter table ...
>>>> > --disable_info
>>>> > and make sure that the table contains at least 1 row when the ALTER
>>>> > TABLE is executed. In that way, ALGORITHM=COPY will report that a
>>>> > nonzero amount of rows were affected, while the native ALTER would
>>>> > report that 0 rows were affected.
>>>>
>>>> I added this into the new tests in the end of instant_alter_charset.test
>>>>
>>>> Note, I didn't add this into original MDEV-15564 tests,
>>>> as they mostly use empty tables.
>>>>
>>>> >
>>>> > I would also suggest testing with some bad data (non-ASCII chars in
>>>> > ASCII column, or Unicode surrogate pairs in UCS2) to see what kind of
>>>> > errors would be triggered (if any), or what the converted data would
>>>> > look like after ALTER IGNORE TABLE.
>>>>
>>>> This is a very good idea. I've just added "ALTER IGNORE"s
>>>> into the new tests.
>>>>
>>>> >
>>>> > Please run the commit comment through a spell-checker. I spotted the
>>>> > typos "correspoding" and "actuallt".
>>>>
>>>> Done.
>>>>
>>>> >
>>>> > Also, please mention in the commit comment that these are regressions
>>>> > caused by MDEV-15564. That should make our lifes easier, should we
>>>> > ever decide to backport MDEV-15564 to earlier versions.
>>>>
>>>> Done.
>>>>
>>>> >
>>>> > I will review the code and tests in detail next week. I hope that
>>>> > Eugene can review it as well.
>>>> >
>>>> > Best regards,
>>>> >
>>>> > Marko
>>>> >
>>>
>>> --
>>> Marko Mäkelä, Lead Developer InnoDB
>>> MariaDB Corporation
--
Eugene
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