maria-developers team mailing list archive

[Oleksandr Byelkin <sanja@xxxxxxxxxxxx>]

Hi!

27.12.2011 20:46, Igor Babaev пишет:
> At file:///home/igor/maria/maria-5.2-bug904345/
>
> ------------------------------------------------------------
> revno: 3077
> revision-id: igor@xxxxxxxxxxxx-20111227184559-v7hlo1h98dz8ui32
> parent: wlad@xxxxxxxxxxxxxxxx-20111223140257-k34gmwhs5msbc57k
> committer: Igor Babaev<igor@xxxxxxxxxxxx>
> branch nick: maria-5.2-bug904345
> timestamp: Tue 2011-12-27 10:45:59 -0800
> message:
>    Fixed LP bug #904345.
>
>    The MIN/MAX optimizer code from the function opt_sum_query erroneously
>    did not take into account conjunctive conditions that did not depend on
>    any table, yet were not identified as constant items. These could be
>    items containing rand() or PS/SP parameters. These items are supposed
>    to be evaluated at the execution phase. That's why if such conditions
>    can be extracted from the WHERE condition the MIN/MAX optimization is
>    not applied as currently it is always done at the optimization phase.
>
>    (In 5.3 expensive subqueries are also evaluated only at the execution
>    phase. So, if a constant condition with such subquery can be extracted
>    from the WHERE clause the MIN/MAX optimization should not be applied
>    in 5.3.)
>
>    IF an IN/ALL/SOME predicate with a constant left part is transformed
>    into an EXISTS subquery the resulting subquery should not be considered
>    uncacheable if the right part of the predicate is not uncacheable.
>
>    Backported the function dbug_print_item() from 5.3. The function is used
>    only for debugging.
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> === modified file 'sql/item.cc'
> --- a/sql/item.cc	2011-11-24 16:48:58 +0000
> +++ b/sql/item.cc	2011-12-27 18:45:59 +0000
> @@ -7915,6 +7915,22 @@
>     ((TABLE_LIST *)data)->hide_view_error(thd);
>   }
>
> +/* Debugger help function */
> +static char dbug_item_print_buf[256];
> +
> +const char *dbug_print_item(Item *item)
> +{
> +  char *buf= dbug_item_print_buf;
> +  String str(buf, sizeof(dbug_item_print_buf),&my_charset_bin);
> +  str.length(0);
> +  if (!item)
> +    return "(Item*)NULL";
> +  item->print(&str ,QT_ORDINARY);
> +  if (str.c_ptr() == buf)
> +    return buf;
> +  else
> +    return "Couldn't fit into buffer";
> +}
This should be put under #ifndef DBUG_OFF

Everything else looks OK to be pushed.

[skip]