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MDEV-18553: MDEV-16327 pre-requisits part 1: isolation of LIMIT/OFFSET handling

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This commit is contained in:
Oleksandr Byelkin
2019-09-26 09:49:50 +02:00
parent 8336371441
commit eb0804ef5e
18 changed files with 198 additions and 154 deletions
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40
sql/sql_union.cc
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@@ -111,11 +111,8 @@ int select_unit::send_data(List<Item> &values)
{
int rc= 0;
int not_reported_error= 0;
if (unit->offset_limit_cnt)
{ // using limit offset,count
unit->offset_limit_cnt--;
return 0;
}
if (unit->lim.check_and_move_offset())
return 0; // using limit offset,count
if (thd->killed == ABORT_QUERY)
return 0;
if (table->no_rows_with_nulls)
@@ -607,12 +604,8 @@ int select_unit_ext::send_data(List<Item> &values)
int rc= 0;
int not_reported_error= 0;
int find_res;
if (unit->offset_limit_cnt)
{
/* using limit offset,count */
unit->offset_limit_cnt--;
if (unit->lim.check_and_move_offset())
return 0;
}
if (thd->killed == ABORT_QUERY)
return 0;
if (table->no_rows_with_nulls)
@@ -1358,8 +1351,7 @@ bool st_select_lex_unit::prepare(TABLE_LIST *derived_arg,
else
{
sl->join->result= result;
select_limit_cnt= HA_POS_ERROR;
offset_limit_cnt= 0;
lim.set_unlimited();
if (!sl->join->procedure &&
result->prepare(sl->join->fields_list, this))
{
@@ -2046,7 +2038,7 @@ bool st_select_lex_unit::optimize()
if (sl->tvc)
{
sl->tvc->select_options=
(select_limit_cnt == HA_POS_ERROR || sl->braces) ?
(lim.is_unlimited() || sl->braces) ?
sl->options & ~OPTION_FOUND_ROWS : sl->options | found_rows_for_union;
if (sl->tvc->optimize(thd))
{
@@ -2066,13 +2058,13 @@ bool st_select_lex_unit::optimize()
set_limit(sl);
if (sl == global_parameters() || describe)
{
offset_limit_cnt= 0;
lim.remove_offset();
/*
We can't use LIMIT at this stage if we are using ORDER BY for the
whole query
*/
if (sl->order_list.first || describe)
select_limit_cnt= HA_POS_ERROR;
lim.set_unlimited();
}
/*
@@ -2081,7 +2073,7 @@ bool st_select_lex_unit::optimize()
Otherwise, SQL_CALC_FOUND_ROWS should be done on all sub parts.
*/
sl->join->select_options=
(select_limit_cnt == HA_POS_ERROR || sl->braces) ?
(lim.is_unlimited() || sl->braces) ?
sl->options & ~OPTION_FOUND_ROWS : sl->options | found_rows_for_union;
saved_error= sl->join->optimize();
@@ -2161,13 +2153,13 @@ bool st_select_lex_unit::exec()
set_limit(sl);
if (sl == global_parameters() || describe)
{
offset_limit_cnt= 0;
lim.remove_offset();
/*
We can't use LIMIT at this stage if we are using ORDER BY for the
whole query
*/
if (sl->order_list.first || describe)
select_limit_cnt= HA_POS_ERROR;
lim.set_unlimited();
}
/*
@@ -2178,14 +2170,14 @@ bool st_select_lex_unit::exec()
if (sl->tvc)
{
sl->tvc->select_options=
(select_limit_cnt == HA_POS_ERROR || sl->braces) ?
(lim.is_unlimited() || sl->braces) ?
sl->options & ~OPTION_FOUND_ROWS : sl->options | found_rows_for_union;
saved_error= sl->tvc->optimize(thd);
}
else
{
sl->join->select_options=
(select_limit_cnt == HA_POS_ERROR || sl->braces) ?
(lim.is_unlimited() || sl->braces) ?
sl->options & ~OPTION_FOUND_ROWS : sl->options | found_rows_for_union;
saved_error= sl->join->optimize();
}
@@ -2208,9 +2200,7 @@ bool st_select_lex_unit::exec()
}
if (!sl->tvc)
saved_error= sl->join->error;
offset_limit_cnt= (ha_rows)(sl->offset_limit ?
sl->offset_limit->val_uint() :
0);
lim.reset();
if (likely(!saved_error))
{
examined_rows+= thd->get_examined_row_count();
@@ -2237,8 +2227,8 @@ bool st_select_lex_unit::exec()
DBUG_RETURN(1);
}
}
if (found_rows_for_union && !sl->braces &&
select_limit_cnt != HA_POS_ERROR)
if (found_rows_for_union && !sl->braces &&
!lim.is_unlimited())
{
/*
This is a union without braces. Remember the number of rows that