maria-developers team mailing list archive
Mailing list archive
Re: Review: MDEV-29075 Changing explicit_defaults_for_timestamp within stored procedure works inconsistently
On Jul 29, Alexander Barkov wrote:
> Hello Sergei,
> I have a couple of suggestions:
> > commit 7b8304045272111a6f4d44196d6b37cbfef06f37
> > Author: Sergei Golubchik <serg@xxxxxxxxxxx>
> > Date: Wed Jul 20 17:31:48 2022 +0200
> > MDEV-29075 Changing explicit_defaults_for_timestamp within stored procedure works inconsistently
> > move the OPTION_EXPLICIT_DEF_TIMESTAMP check from the parsing step
> > to the execution
> > > diff --git a/sql/field.cc b/sql/field.cc
> > index 2e0c70d3d13..23ebb07b7f7 100644
> > --- a/sql/field.cc
> > +++ b/sql/field.cc
> > @@ -10824,6 +10824,7 @@ Column_definition::Column_definition(
> > comment= old_field->comment;
> > vcol_info= old_field->vcol_info;
> > option_list= old_field->option_list;
> > + explicitly_nullable= !(old_field->flags & NOT_NULL_FLAG);
> This introduces asymmetry in how NULL and NOT NULL attributes are handled.
> I suggest considering these ways:
> 1. Change "bool explicitly_nullable" to "bool explicit_nullability",
> which will be:
> - false if nothing was specified
> - true if NULL or NOT NULL was specified.
I've done that, see commit 7120195ac1c,
but I don't like how it looks. When NOT_NULL_FLAG is set, the value is
redundant, it's not used anywhere and only adds few pointless
assignments to sql_yacc.yy.
We only need to know how to interpret the case when NOT_NULL_FLAG is not
set, that's what explicitly_nullable was doing.
> 2. Or don't store NOT_NULL_FLAG in Column_definition::flags at all.
> Add a new Column_definition enum member with three values for:
> - not specified
> - explicit NULL
> - explicit NOT NULL
> As discussed on slack, the latter will need some changes.
> But I think not that much, as only Column_definition needs changes,
> while Field does not seem to need at this point.
I don't know how to do it in a robust way. Column_definition and Field
have both the same flags member, one typically just copies it back and
forth. Having just one bit out of Column_definition::flags is very
error-prone, I'd prefer all flags to be stored very differently in
Column_definition, so that one couldn't just copy them. But this
explicitly_nullable thing cannot justify such a big change.
VP of MariaDB Server Engineering