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 <[email protected]> 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 Mobile Phone: +86 18658156856 (Hangzhou) Gtalk: penglixun(at)gmail.com Twitter: http://www.twitter.com/plinux Blog: http://www.penglixun.com
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