Materialized_cursor Class Reference

Materialized_cursor – an insensitive materialized server-side cursor. More...

Inheritance diagram for Materialized_cursor:

Public Member Functions
	Materialized_cursor (Query_result *result)
void	set_table (TABLE *table_arg)
	Bind a temporary table with a materialized cursor. More...
void	set_result (Query_result *result_arg)
int	send_result_set_metadata (THD *thd, const mem_root_deque< Item * > &send_result_set_metadata)
	Preserve the original metadata to be sent to the client. More...
bool	is_open () const override
bool	open (THD *) override
bool	fetch (ulong num_rows) override
	Fetch up to the given number of rows from a materialized cursor. More...
void	close () override
	~Materialized_cursor () override
Public Member Functions inherited from Server_side_cursor
	Server_side_cursor (Query_result *result_arg)
virtual	~Server_side_cursor ()

Private Attributes
Query_expression	fake_query_expression
	A fake unit to supply to Query_result_send when fetching. More...
TABLE *	m_table {nullptr}
	Cursor to the table that contains the materialized result. More...
mem_root_deque< Item * >	item_list
	List of items to send to client, copy of original items, but created in the cursor object's mem_root. More...
ulong	fetch_limit {0}
ulong	fetch_count {0}
bool	is_rnd_inited {false}

Additional Inherited Members
Static Public Member Functions inherited from Server_side_cursor
static void *	operator new (size_t size, MEM_ROOT *mem_root, const std::nothrow_t &=std::nothrow) noexcept
static void	operator delete (void *, size_t)
static void	operator delete (void *, MEM_ROOT *, const std::nothrow_t &) noexcept
Public Attributes inherited from Server_side_cursor
MEM_ROOT	mem_root {key_memory_TABLE, 1024}
	For allocation of Handler objects for the temporary table. More...
Protected Attributes inherited from Server_side_cursor
Query_arena	m_arena
Query_result *	m_result
	Row destination used for fetch. More...

Detailed Description

Materialized_cursor – an insensitive materialized server-side cursor.

The result set of this cursor is saved in a temporary table at open. The cursor itself is simply an interface for the handler of the temporary table.

The materialized cursor is usually attached to a preparable statement through a query result object. The lifetime of the cursor is the same as the lifetime of the preparable statement. When the preparable statement is destroyed, the materialized cursor (including the temporary table) is also destroyed.

Constructor & Destructor Documentation

Materialized_cursor()

Materialized_cursor::Materialized_cursor

(

Query_result *

result

)

~Materialized_cursor()

Materialized_cursor::~Materialized_cursor ( )

override

Member Function Documentation

close()

void Materialized_cursor::close ( void  )

overridevirtual

Implements Server_side_cursor.

fetch()

bool Materialized_cursor::fetch ( ulong  num_rows )

overridevirtual

Fetch up to the given number of rows from a materialized cursor.

Precondition: the cursor is open.

If the cursor points after the last row, the fetch will automatically close the cursor and not send any data (except the 'EOF' packet with SERVER_STATUS_LAST_ROW_SENT). This is an extra round trip and probably should be improved to return SERVER_STATUS_LAST_ROW_SENT along with the last row.

Implements Server_side_cursor.

is_open()

bool Materialized_cursor::is_open ( ) const

inlineoverridevirtual

Implements Server_side_cursor.

open()

bool Materialized_cursor::open ( THD *  thd )

overridevirtual

Implements Server_side_cursor.

send_result_set_metadata()

int Materialized_cursor::send_result_set_metadata	(	THD *	thd,
		const mem_root_deque< Item * > &	send_result_set_metadata
	)

Preserve the original metadata to be sent to the client.

Initiate sending of the original metadata to the client (call Protocol::send_result_set_metadata()).

Parameters

thd	Thread identifier.
send_result_set_metadata	List of fields that would be sent.

set_result()

void Materialized_cursor::set_result ( Query_result *  result_arg )

inline

set_table()

void Materialized_cursor::set_table

(

TABLE *

table_arg

)

Bind a temporary table with a materialized cursor.

Member Data Documentation

fake_query_expression

Query_expression Materialized_cursor::fake_query_expression

private

A fake unit to supply to Query_result_send when fetching.

fetch_count

ulong Materialized_cursor::fetch_count {0}

private

fetch_limit

ulong Materialized_cursor::fetch_limit {0}

private

is_rnd_inited

bool Materialized_cursor::is_rnd_inited {false}

private

item_list

mem_root_deque<Item *> Materialized_cursor::item_list

private

List of items to send to client, copy of original items, but created in the cursor object's mem_root.

m_table

TABLE* Materialized_cursor::m_table {nullptr}

private

Cursor to the table that contains the materialized result.

---

The documentation for this class was generated from the following file:

• sql/sql_cursor.cc