window.h File Reference

#include <assert.h>
#include <sys/types.h>
#include <cstring>
#include "my_inttypes.h"
#include "sql/enum_query_type.h"
#include "sql/handler.h"
#include "sql/mem_root_array.h"
#include "sql/sql_lex.h"
#include "sql/sql_list.h"
#include "sql/table.h"
#include "sql/window_lex.h"

Go to the source code of this file.

Classes
class	Window
	Represents the (explicit) window of a SQL 2003 section 7.11 <window clause>, or the implicit (inlined) window of a window function call, or a reference to a named window in a window function call (instead of the inlined definition) before resolution. More...
struct	Window::st_offset
struct	Window::st_ll_offset
struct	Window::st_nth
struct	Window::st_lead_lag
struct	Window::Frame_buffer_position
	Holds information about a position in the buffer frame as stored in a temporary file (cf. More...
struct	Window_evaluation_requirements
	Collects evaluation requirements from a window function, used by Item_sum::check_wf_semantics and its overrides. More...

Enumerations
enum class	Window_retrieve_cached_row_reason {   WONT_UPDATE_HINT = -1 , FIRST_IN_PARTITION = 0 , CURRENT = 1 , FIRST_IN_FRAME = 2 ,   LAST_IN_FRAME = 3 , LAST_IN_PEERSET = 4 , MISC_POSITIONS = 5 }
	Position hints for the frame buffer are saved for these kind of row accesses, cf. More...

Variables
constexpr int	kMaxWindows = 127
	The number of windows is limited to avoid the stack blowing up when constructing iterators recursively. More...

Enumeration Type Documentation

Window_retrieve_cached_row_reason

enum class Window_retrieve_cached_row_reason

strong

Position hints for the frame buffer are saved for these kind of row accesses, cf.

Window::m_frame_buffer_positions.

Enumerator
WONT_UPDATE_HINT
FIRST_IN_PARTITION
CURRENT
FIRST_IN_FRAME
LAST_IN_FRAME
LAST_IN_PEERSET
MISC_POSITIONS

Variable Documentation

kMaxWindows

constexpr int kMaxWindows = 127

constexpr

The number of windows is limited to avoid the stack blowing up when constructing iterators recursively.

There used to be no limit, but it would be unsafe since QEP_shared::m_idx of tmp tables assigned for windows would exceed the old range of its type plan_idx (int8). It has now been widened, so the max number of windows could be increased if need be, modulo other problems. We could also make it a system variable.