maria-developers team mailing list archive

[Sergei Golubchik <serg@xxxxxxxxxxx>]

Hi, Alexander!

On Nov 13, Alexander Barkov wrote:
> >
> > [Commits] 2c904b9: parser cleanup: don't store field properties in LEX, use Create_field directly
> > serg at mariadb.org serg at mariadb.org
> > Mon Nov 10 11:26:48 EET 2014
> >
> >     Previous message: [Commits] Rev 4344: MDEV-6179: dynamic columns functions/cast()/convert() doesn't play nice with CREATE/ALTER TABLE in lp:~maria-captains/maria/5.5
> >     Next message: [Commits] Rev 4345: MDEV-6862 "#error <my_config.h>" and third-party libraries in lp:~maria-captains/maria/5.5
> >     Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
> >
> > revision-id: 2c904b937b5ef7fbec60ebb9cb514a501c5bd8e4
> > parent(s): f59588b9112965849986c45fcd150d9abed74063
> > committer: Sergei Golubchik
> > branch nick: maria
> > timestamp: 2014-11-09 22:33:17 +0100
> > message:
> >
> > parser cleanup: don't store field properties in LEX, use Create_field directly
> >
> > length/dec/charset are still in LEX, because they're also used
> > for CAST and dynamic columns.
> >
> > also
> > 1. fix "MDEV-7041 COLLATION(CAST('a' AS CHAR BINARY)) returns a wrong result"
> > 2. allow BINARY modifier in stored function RETURN clause
> > 3. allow "COLLATION without CHARSET" in SP/SF (parameters, RETURN, DECLARE)
> > 4. print correct variable name in error messages for stored routine parameters
> 
> A very nice clean up.
> 
> I only found it a little bit not easy to track that
> all Lex and Create_field attributes get initialized and copied to each 
> other properly.
> 
> I suggest to go a little bit further and get rid from Lex->dec, 
> Lex->length and Lex->charset at all, and write the attributes directly
> to the destination as soon as they get parsed. See a proposed addon
> patch attached.

I don't like very much all that LEX::last_field thing, but it existed
already and I reused it. But I'd rather not introduce more
LEX::last_attr or LEX::last_whatever members unless absolutely
necessary. I generally prefer to pass data via the parser stack.

That's what I did in fixing this dyncol bug. As I've found in this
cleanup, and as you've seen in review, dynamic columns, CAST,
and field declarations all use LEX::length/etc - so using CAST or
dyncols in a virtual column will overwrite field's declaration.
Recently Kolbe found this as well and reported a bug for 5.5, MDEV-6179.
I've fixed it by creating LEX_TYPE structure - I didn't remove
length/etc from LEX in 5.5, but if this patch will be merged in 10.1, it
could easily allow to remove them from LEX.

So, I would rather postpone any further LEX changes until 10.0 merge.
Then I can show you the next cleanup patch. In fact, if I'd have checked
Jira bugs before doing this cleanup, I would've started from 5.5 bugfix
and then would've done the rest on top of it. But now I'm facing an
"interesting" merge ahead :)

(LEX_TYPE in 5.5 is basically your Create_type_attributes_st without
m_length_was_set_explicitly - as it's not needed in 5.5 - and with
enum_field_types type).

> > diff --git a/mysql-test/r/cast.result b/mysql-test/r/cast.result
> > index c81af13..8ad4568 100644
> > --- a/mysql-test/r/cast.result
> > +++ b/mysql-test/r/cast.result
> > @@ -796,3 +796,32 @@ DATE("foo")
> >  NULL
> >  Warnings:
> >  Warning	1292	Incorrect datetime value: 'foo'
> > +create table t1 (a int, b char(5) as (cast("a" as char(10) binary) + a) );
> > +show create table t1;
> > +Table	Create Table
> > +t1	CREATE TABLE `t1` (
> > +  `a` int(11) DEFAULT NULL,
> > +  `b` char(5) AS (cast("a" as char(10) binary) + a) VIRTUAL
> > +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> > +drop table t1;
> > +select collation(cast("a" as char(10) binary));
> > +collation(cast("a" as char(10) binary))
> > +latin1_bin
> > +select collation(cast("a" as char(10) charset utf8 binary));
> > +collation(cast("a" as char(10) charset utf8 binary))
> > +utf8_bin
> > +select collation(cast("a" as char(10) ascii binary));
> > +collation(cast("a" as char(10) ascii binary))
> > +latin1_bin
> > +select collation(cast("a" as char(10) unicode binary));
> > +collation(cast("a" as char(10) unicode binary))
>  > +ucs2_bin
> 
> UNICODE is an alias for UCS2, which is not always compiled.
> Please move ucs2 related tests to ctype_ucs.test.

Sure.

> <skip>
> You removed this code in field.cc:
> 
> > -  if (fld_length != NULL)
> > -  {
> > -    errno= 0;
> > -    length= strtoul(fld_length, NULL, 10);
> > -    if ((errno != 0) || (length > MAX_FIELD_BLOBLENGTH))
> > -    {
> > -      my_error(ER_TOO_BIG_DISPLAYWIDTH, MYF(0), fld_name, MAX_FIELD_BLOBLENGTH);
> > -      DBUG_RETURN(TRUE);
> > -    }
> > -
> > -    if (length == 0)
> > -      fld_length= NULL; /* purecov: inspected */
> > -  }
> 
> and added this in sql_yacc.yy:
> 
> > +  if (length)
> > +  {
> > +    int err;
> > +    last_field->length= (ulong)my_strtoll10(length, NULL, &err);
> > +    if (err)
> > +      last_field->length= ~0UL; // safety
> > +  }
> > +  else
> > +    last_field->length= 0;
> 
> 
> I have a feeling that on a 32bit platforms it will stop sending errors
> on attempt to create a blob larger that 4Gb.
> last_field->length is ulong, which is 32bit is a 32 bit platform,
> and it gets assigned to a 64 bit value.

Indeed, good catch.
I'll fix it.

Regards,
Sergei