maria-developers team mailing list archive

[Davi Arnaut <davi@xxxxxxxxxxxxxxx>]

There is also sql_safe_updates which (among other things) will cause
updates/deletes not using keys to fail. Also, MySQL 5.6 made an attempt at
fixing the replication part of this issue (see slave_allow_batching and
slave-rows-search-algorithms).

Davi


On Wed, Jun 19, 2013 at 2:40 AM, Lixun Peng <penglixun@xxxxxxxxx> wrote:

> Hi Sergei,
>
> You are right, let users add primary key is best.
> But I can't let users who don't want to create primary key can't use our
> MySQL service.
> Amazon RDS also allow users to create the tables without primary key, just
> change binlog_format to MIXED to solve replication problem.
>
> I think this feature is very useful for any MySQL cloud service providers,
> all of them will face this problem in one day.
> I will try to do some analysis/research in this feature implement first, I
> will need your help :-)
>
> I will notice any new updates in this email.
>
>
> Thanks,
> Lixun
>
>
>
>
> On Wed, Jun 19, 2013 at 5:14 PM, Sergei Golubchik <serg@xxxxxxxxxxx>wrote:
>
>> Hi, Lixun!
>>
>>
>> On Jun 18, Lixun Peng wrote:
>> > Hi,
>> >
>> > As we know, InnoDB has implicit primary key if a table hasn't defined
>> > a primary key.  However MySQL server doesn't know this primary key, so
>> > this primary key will not apear in binlog.
>> >
>> > When we are using ROW format binlog for replication, if a table has no
>> any
>> > indexes, that's a disaster. If a table without indexes do a DML
>> > (UPDATE/DELETE), of course it will run a long time in master, but in
>> slave,
>> > it still need a long time. It will cause serious slave replication
>> delay.
>> ...
>>
>> > I think mysql server can do the same thing as InnoDB do, if user doesn't
>> > define the primary key, mysql can add the primary key automatically.
>> >
>> > How do you think?
>>
>> Well, that's doable. A much easier solution would be to require a user
>> to create a primary key. It's a one-line change:
>>
>> -  Table_flags ha_table_flags() const { return cached_table_flags; }
>> +  Table_flags ha_table_flags() const { return cached_table_flags |
>> HA_REQUIRE_PRIMARY_KEY; }
>>
>> But what you suggest is possible too, I believe.
>>
>> Regards,
>> Sergei
>>
>
>
>
> --
> Senior Database Engineer @ Taobao.com
>
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