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Rename window frame start/end to top/bottom. Bikeshed should be green.

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This commit is contained in:
Sergei Petrunia
2016-03-02 13:02:58 +03:00
parent 7ee0140149
commit dedf87fdf4
1 changed files with 34 additions and 34 deletions
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68
sql/sql_window.cc
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@ -358,7 +358,7 @@ public:
{
/*
UNBOUNDED PRECEDING frame end just stays on the first row.
We are start of the frame, so we don't need to update the sum function.
We are top of the frame, so we don't need to update the sum function.
*/
}
@ -418,8 +418,8 @@ public:
class Frame_n_rows : public Frame_cursor
{
/* Whether this start of frame or end of rame */
const bool is_start;
/* Whether this is top of the frame or bottom */
const bool is_top_bound;
const ha_rows n_rows;
const bool is_preceding;
@ -432,8 +432,8 @@ class Frame_n_rows : public Frame_cursor
bool at_partition_start;
bool at_partition_end;
public:
Frame_n_rows(bool is_start_arg, bool is_preceding_arg, ha_rows n_rows_arg) :
is_start(is_start_arg), n_rows(n_rows_arg), is_preceding(is_preceding_arg)
Frame_n_rows(bool is_top_bound_arg, bool is_preceding_arg, ha_rows n_rows_arg) :
is_top_bound(is_top_bound_arg), n_rows(n_rows_arg), is_preceding(is_preceding_arg)
{}
void init(THD *thd, READ_RECORD *info, SQL_I_List<ORDER> *partition_list)
@ -464,7 +464,7 @@ public:
break;
}
}
n_rows_to_skip= n_rows - (is_start? 0:1);
n_rows_to_skip= n_rows - (is_top_bound? 0:1);
}
else
{
@ -474,19 +474,19 @@ public:
*/
n_rows_to_skip= 0;
if (!first && (!is_start || n_rows))
if (!first && (!is_top_bound || n_rows))
{
// We are positioned at the first row in the partition:
if (is_start) // this is frame start endpoint
if (is_top_bound) // this is frame top endpoint
item->remove();
else
item->add();
}
/*
Note: i_end=-1 when this is a start-endpoint "CURRENT ROW" which is
Note: i_end=-1 when this is a top-endpoint "CURRENT ROW" which is
implemented as "ROWS 0 FOLLOWING".
*/
longlong i_end= n_rows + (first?1:0)- is_start;
longlong i_end= n_rows + (first?1:0)- is_top_bound;
for (longlong i= 0; i < i_end; i++)
{
if (next_row_intern(item))
@ -517,7 +517,7 @@ private:
bool new_group= bound_tracker.check_if_next_group();
if (at_partition_start || !new_group)
{
if (is_start) // this is frame start endpoint
if (is_top_bound) // this is frame start endpoint
item->remove();
else
item->add();
@ -541,13 +541,13 @@ private:
class Frame_current_row : public Frame_n_rows
{
public:
Frame_current_row(bool is_start_arg) :
Frame_n_rows(is_start_arg, false /*is_preceding*/, ha_rows(0))
Frame_current_row(bool is_top_bound_arg) :
Frame_n_rows(is_top_bound_arg, false /*is_preceding*/, ha_rows(0))
{}
};
Frame_cursor *get_frame_cursor(Window_frame_bound *bound, bool is_start_bound)
Frame_cursor *get_frame_cursor(Window_frame_bound *bound, bool is_top_bound)
{
if (bound->precedence_type == Window_frame_bound::PRECEDING ||
bound->precedence_type == Window_frame_bound::FOLLOWING)
@ -564,12 +564,12 @@ Frame_cursor *get_frame_cursor(Window_frame_bound *bound, bool is_start_bound)
}
longlong n_rows= bound->offset->val_int();
return new Frame_n_rows(is_start_bound, is_preceding, n_rows);
return new Frame_n_rows(is_top_bound, is_preceding, n_rows);
}
if (bound->precedence_type == Window_frame_bound::CURRENT)
{
return new Frame_current_row(is_start_bound);
return new Frame_current_row(is_top_bound);
}
return NULL;
}
@ -582,7 +582,7 @@ Frame_cursor *get_frame_cursor(Window_frame_bound *bound, bool is_start_bound)
cursors:
- current row - the row that we're computing window func value for)
- start_bound - the start of the frame
- end_bound - the end of the frame
- bottom_bound - the end of the frame
All three cursors move together.
@ -616,8 +616,8 @@ bool compute_window_func_with_frames(Item_window_func *item_win,
{
THD *thd= current_thd;
int err= 0;
Frame_cursor *start_bound;
Frame_cursor *end_bound;
Frame_cursor *top_bound;
Frame_cursor *bottom_bound;
Item_sum *sum_func= item_win->window_func;
/* This algorithm doesn't support DISTINCT aggregator */
@ -625,11 +625,11 @@ bool compute_window_func_with_frames(Item_window_func *item_win,
Window_frame *window_frame= item_win->window_spec->window_frame;
DBUG_ASSERT(window_frame->units == Window_frame::UNITS_ROWS);
start_bound= get_frame_cursor(window_frame->top_bound, true);
end_bound= get_frame_cursor(window_frame->bottom_bound, false);
top_bound= get_frame_cursor(window_frame->top_bound, true);
bottom_bound= get_frame_cursor(window_frame->bottom_bound, false);
start_bound->init(thd, info, &item_win->window_spec->partition_list);
end_bound->init(thd, info, &item_win->window_spec->partition_list);
top_bound->init(thd, info, &item_win->window_spec->partition_list);
bottom_bound->init(thd, info, &item_win->window_spec->partition_list);
bool is_error= false;
bool first_row= true;
@ -641,14 +641,14 @@ bool compute_window_func_with_frames(Item_window_func *item_win,
{
/* Start the first partition */
sum_func->clear();
end_bound->next_partition(true, sum_func);
start_bound->next_partition(true, sum_func);
bottom_bound->next_partition(true, sum_func);
top_bound->next_partition(true, sum_func);
}
else
{
/* These can write into tbl->record[0] */
end_bound->next_row(sum_func);
start_bound->next_row(sum_func);
bottom_bound->next_row(sum_func);
top_bound->next_row(sum_func);
}
if ((err=info->read_record(info)))
@ -667,17 +667,17 @@ bool compute_window_func_with_frames(Item_window_func *item_win,
memcpy(rowid_buf, tbl->file->ref, tbl->file->ref_length);
/*
Ok, the current row is the first row in the new partition.
We move end_bound first, because we want rows to be added into the
aggregate before start_bound attempts to remove them.
We move bottom_bound first, because we want rows to be added into the
aggregate before top_bound attempts to remove them.
*/
end_bound->next_partition(false, sum_func);
bottom_bound->next_partition(false, sum_func);
/*
The problem is, the above call may have made tbl->record[0] to point to
some other record.
*/
tbl->file->ha_rnd_pos(tbl->record[0], rowid_buf);
start_bound->next_partition(false, sum_func);
top_bound->next_partition(false, sum_func);
/*
The same problem again. The above call may have moved table's current
@ -699,8 +699,8 @@ bool compute_window_func_with_frames(Item_window_func *item_win,
}
my_free(rowid_buf);
delete start_bound;
delete end_bound;
delete top_bound;
delete bottom_bound;
return is_error? true: false;
}
@ -906,7 +906,7 @@ bool JOIN::process_window_functions(List<Item> *curr_fields_list)
{
/*
Frame-aware window function computation. It does one pass, but
uses three cursors -frame_start, current_row, and frame_end.
uses three cursors -frame_top, current_row, and frame_bottom.
*/
if (compute_window_func_with_frames(item_win, tbl, &info))
is_error= true;