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Merge branch '10.2-mdev9197-cons' of github.com:shagalla/server

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into branch 10.2-mdev9197.
This commit is contained in:
Igor Babaev
2016-08-31 16:16:54 -07:00
parent 670760d504 eb2c147475
commit 3fb4f9bb93
30 changed files with 8926 additions and 14 deletions
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134
sql/sql_derived.cc
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@ -1100,3 +1100,137 @@ bool mysql_derived_reinit(THD *thd, LEX *lex, TABLE_LIST *derived)
unit->set_thd(thd);
DBUG_RETURN(FALSE);
}
/**
@brief
Extract the condition depended on derived table/view and pushed it there
@param thd The thread handle
@param cond The condition from which to extract the pushed condition
@param derived The reference to the derived table/view
@details
This functiom builds the most restrictive condition depending only on
the derived table/view that can be extracted from the condition cond.
The built condition is pushed into the having clauses of the
selects contained in the query specifying the derived table/view.
The function also checks for each select whether any condition depending
only on grouping fields can be extracted from the pushed condition.
If so, it pushes the condition over grouping fields into the where
clause of the select.
@retval
true if an error is reported
false otherwise
*/
bool pushdown_cond_for_derived(THD *thd, Item *cond, TABLE_LIST *derived)
{
if (!cond)
return false;
/*
Build the most restrictive condition extractable from 'cond'
that can be pushed into the derived table 'derived'.
All subexpressions of this condition are cloned from the
subexpressions of 'cond'.
This condition has to be fixed yet.
*/
Item *extracted_cond;
derived->check_pushable_cond_for_table(cond);
extracted_cond= derived->build_pushable_cond_for_table(thd, cond);
if (!extracted_cond)
{
/* Nothing can be pushed into the derived table */
return false;
}
/* Push extracted_cond into every select of the unit specifying 'derived' */
st_select_lex_unit *unit= derived->get_unit();
st_select_lex *save_curr_select= thd->lex->current_select;
st_select_lex *sl= unit->first_select();
for (; sl; sl= sl->next_select())
{
thd->lex->current_select= sl;
/*
For each select of the unit except the last one
create a clone of extracted_cond
*/
Item *extracted_cond_copy= !sl->next_select() ? extracted_cond :
extracted_cond->build_clone(thd, thd->mem_root);
if (!extracted_cond_copy)
continue;
/*
Figure out what can be extracted from the pushed condition
that could be pushed into the where clause of sl
*/
Item *cond_over_grouping_fields;
sl->collect_grouping_fields(thd);
sl->check_cond_extraction_for_grouping_fields(extracted_cond_copy,
&Item::exclusive_dependence_on_grouping_fields_processor);
cond_over_grouping_fields=
sl->build_cond_for_grouping_fields(thd, extracted_cond_copy, true);
/*
Transform the references to the 'derived' columns from the condition
pushed into the where clause of sl to make them usable in the new context
*/
if (cond_over_grouping_fields)
cond_over_grouping_fields= cond_over_grouping_fields->transform(thd,
&Item::derived_field_transformer_for_where,
(uchar*) sl);
if (cond_over_grouping_fields)
{
/*
In extracted_cond_copy remove top conjuncts that
has been pushed into the where clause of sl
*/
extracted_cond_copy= remove_pushed_top_conjuncts(thd, extracted_cond_copy);
/*
Create the conjunction of the existing where condition of sl
and the pushed condition, take it as the new where condition of sl
and fix this new condition
*/
cond_over_grouping_fields->walk(&Item::cleanup_processor, 0, 0);
thd->change_item_tree(&sl->join->conds,
and_conds(thd, sl->join->conds,
cond_over_grouping_fields));
if (sl->join->conds->fix_fields(thd, &sl->join->conds))
goto err;
if (!extracted_cond_copy)
continue;
}
/*
Transform the references to the 'derived' columns from the condition
pushed into the having clause of sl to make them usable in the new context
*/
extracted_cond_copy= extracted_cond_copy->transform(thd,
&Item::derived_field_transformer_for_having,
(uchar*) sl);
if (!extracted_cond_copy)
continue;
/*
Create the conjunction of the existing having condition of sl
and the pushed condition, take it as the new having condition of sl
and fix this new condition
*/
extracted_cond_copy->walk(&Item::cleanup_processor, 0, 0);
thd->change_item_tree(&sl->join->having,
and_conds(thd, sl->join->having,
extracted_cond_copy));
sl->having_fix_field= 1;
if (sl->join->having->fix_fields(thd, &sl->join->having))
return true;
sl->having_fix_field= 0;
}
thd->lex->current_select= save_curr_select;
return false;
err:
thd->lex->current_select= save_curr_select;
return true;
}