maria-developers team mailing list archive

[Sergei Golubchik <serg@xxxxxxxxxxx>]

Hi, Alexey!

On Feb 04, Alexey Botchkov wrote:
> Hi, Sergei.
> 
> Below are my reply on your comments.
> I think it's better get these agreed before I produce the new patch.
> 
> > > +    if ((sav_inited= f->inited) == RND)
> > > +      f->ha_rnd_end();
> >
> > When can this happen?
> UPDATE statements do the rnd_init() in order to access through rnd_pos,
> and when they need to do the table scan.

So, UPDATE does rnd_init(), then rnd_pos(), then update_row(), and
at that point you need to look up the key in all partitions, so you need
index_read()?

Could you, please, add a comment here to explain this sequence of
events?

> > > +int ha_partition::check_uniques_insert(uchar *buf,
> > > ...
> > > +    {
> >
> > can you use key_copy() here?
> Difficult to use here key_copy() as it is.
> Here i need to get the record from the arbitrary buffer,
> while key_copy() gets it from the table->record[0].
> It seems weird that the key_copy() actually has the 'from_record
> argument, but only uses it to check the null bit.

May be, fix it?
Meaning, adding 'offset' argument to Field::get_key_image(), I suppose.

> > > @@ -283,6 +283,14 @@ class partition_info : public Sql_alloc
> ..
> > > +  uint n_uniques_to_check;
> > > +  uchar *unique_key_buf[2];
> >
> > Is it safe? Isn't partition_info shared between many handlers
> > so that every handler can only use it read-only?
> > it's not quite clear to me. it seems that every TABLE has its own
> > partition_info. But cloned handlers all share the same partition_info.
> 
> You're right, cloned handlers all share the same part_info. I didn't notice
> this.
> So i guess i should move the uniue_key_buf[2] to the class ha_partition.
> Do you know BTW if we ever use cloned handlers to write/update?

I don't know, sorry.

Regards,
Sergei
Chief Architect MariaDB
and security@xxxxxxxxxxx