sp_lex_instr is a class providing the interface and base implementation for SP-instructions, whose execution is based on expression evaluation. More...

#include <sp_instr.h>

Inheritance diagram for sp_lex_instr:

[legend]

Public Member Functions
	sp_lex_instr (uint ip, sp_pcontext ctx, LEX lex, bool is_lex_owner)

	~sp_lex_instr () override

bool	validate_lex_and_execute_core (THD thd, uint nextp, bool open_tables)
	Make a few attempts to execute the instruction. More...

SQL_I_List< Item_trigger_field > *	get_instr_trig_field_list () override

bool	execute (THD thd, uint nextp) override
	Execute this instruction. More...

Public Member Functions inherited from sp_instr
	sp_instr (uint ip, sp_pcontext *ctx)

	~sp_instr () override

virtual PSI_statement_info *	get_psi_info ()=0

uint	get_ip () const

virtual uint	get_cont_dest () const
	Get the continuation destination (instruction pointer for the CONTINUE HANDLER) of this instruction. More...

sp_pcontext *	get_parsing_ctx () const

virtual uint	opt_mark (sp_head , List< sp_instr > leads)
	Mark this instruction as reachable during optimization and return the index to the next instruction. More...

virtual uint	opt_shortcut_jump (sp_head , sp_instr start)
	Short-cut jumps to jumps during optimization. More...

virtual void	opt_move (uint dst, List< sp_branch_instr > *ibp)
	Inform the instruction that it has been moved during optimization. More...

bool	opt_is_marked () const

Public Member Functions inherited from sp_printable
virtual void	print (const THD thd, String str)=0

virtual	~sp_printable ()=default

Protected Member Functions
virtual bool	exec_core (THD thd, uint nextp)=0
	Execute core function of instruction after all preparations (e.g. More...

virtual bool	is_invalid () const =0

virtual void	invalidate ()=0
	Invalidate the object. More...

virtual void	get_query (String *sql_query) const
	Return the query string, which can be passed to the parser. More...

virtual void	adjust_sql_command (LEX *)
	Some expressions may be re-parsed as SELECT statements, but need to be adjusted to another SQL command. More...

virtual LEX_CSTRING	get_expr_query () const

virtual bool	on_after_expr_parsing (THD *thd)
	Callback function which is called after the statement query string is successfully parsed, and the thread context has not been switched to the outer context. More...

virtual void	cleanup_before_parsing (THD *thd)
	Destroy items in the free list before re-parsing the statement query string (and thus, creating new items). More...

Protected Member Functions inherited from sp_instr
void	clear_da (THD *thd) const
	Clear diagnostics area. More...

Protected Attributes
LEX *	m_lex
	LEX-object. More...

Protected Attributes inherited from sp_instr
bool	m_marked
	Show if this instruction is reachable within the SP (used by SP-optimizer). More...

uint	m_ip
	Instruction pointer. More...

sp_pcontext *	m_parsing_ctx
	Instruction parsing context. More...

Private Member Functions
bool	reset_lex_and_exec_core (THD thd, uint nextp, bool open_tables)
	Prepare LEX and thread for execution of instruction, if requested open and lock LEX's tables, execute instruction's core function, perform cleanup afterwards. More...

bool	execute_expression (THD thd, uint nextp)
	Execute an expression (e.g an IF) that is not a complete SQL statement. More...

LEX *	parse_statement (THD thd, sp_head sp)
	Parse statement corresponding to this instruction and return a new LEX. More...

void	set_lex (LEX *lex, bool is_lex_owner)
	Set LEX-object. More...

void	free_lex ()
	Cleanup and destroy assigned LEX-object if needed. More...

Private Attributes
MEM_ROOT	m_lex_mem_root {PSI_NOT_INSTRUMENTED, MEM_ROOT_BLOCK_SIZE}
	Mem-root for storing the LEX-tree during reparse. More...

bool	m_is_lex_owner
	Indicates whether this sp_lex_instr instance is responsible for LEX-object deletion. More...

bool	m_first_execution
	Indicates whether exec_core() has not been already called on the current LEX-object. More...

Table_ref *	m_prelocking_tables
	List of additional tables this statement needs to lock when it enters/leaves prelocked mode on its own. More...

Table_ref **	m_lex_query_tables_own_last
	The value m_lex->query_tables_own_last should be set to this when the statement enters/leaves prelocked mode on its own. More...

SQL_I_List< Item_trigger_field >	m_trig_field_list
	List of all the Item_trigger_field's of instruction. More...

Additional Inherited Members
Public Attributes inherited from sp_instr
Query_arena	m_arena

Detailed Description

sp_lex_instr is a class providing the interface and base implementation for SP-instructions, whose execution is based on expression evaluation.

sp_lex_instr keeps LEX-object to be able to evaluate the expression.

sp_lex_instr also provides possibility to re-parse the original query string if for some reason the LEX-object is not valid any longer.

Constructor & Destructor Documentation

◆ sp_lex_instr()

sp_lex_instr::sp_lex_instr	(	uint	ip,
		sp_pcontext *	ctx,
		LEX *	lex,
		bool	is_lex_owner
	)

inline

◆ ~sp_lex_instr()

sp_lex_instr::~sp_lex_instr ( )

inlineoverride

Member Function Documentation

◆ adjust_sql_command()

virtual void sp_lex_instr::adjust_sql_command ( LEX * )

inlineprotectedvirtual

Some expressions may be re-parsed as SELECT statements, but need to be adjusted to another SQL command.

This function facilitates that change.

Reimplemented in sp_instr_set, sp_instr_freturn, and sp_lex_branch_instr.

◆ cleanup_before_parsing()

void sp_lex_instr::cleanup_before_parsing ( THD * thd )

protectedvirtual

Destroy items in the free list before re-parsing the statement query string (and thus, creating new items).

Parameters

thd	Thread context.

Reimplemented in sp_instr_set_trigger_field.

◆ exec_core()

virtual bool sp_lex_instr::exec_core	(	THD *	thd,
		uint *	nextp
	)

protectedpure virtual

Execute core function of instruction after all preparations (e.g.

setting of proper LEX, saving part of the thread context).

Parameters

	thd	Thread context.
[out]	nextp	next instruction pointer

Returns: Error flag.

Implemented in sp_instr_stmt, sp_instr_set, sp_instr_set_trigger_field, sp_instr_freturn, sp_instr_jump_if_not, sp_instr_set_case_expr, sp_instr_jump_case_when, and sp_instr_cpush.

◆ execute()

bool sp_lex_instr::execute	(	THD *	thd,
		uint *	nextp
	)

inlineoverridevirtual

Execute this instruction.

Parameters

	thd	Thread context
[out]	nextp	index of the next instruction to execute. (For most instructions this will be the instruction following this one). Note that this parameter is undefined in case of errors, use get_cont_dest() to find the continuation instruction for CONTINUE error handlers.

Returns: Error status.

Implements sp_instr.

Reimplemented in sp_instr_stmt, and sp_instr_cpush.

◆ execute_expression()

bool sp_lex_instr::execute_expression	(	THD *	thd,
		uint *	nextp
	)

private

Execute an expression (e.g an IF) that is not a complete SQL statement.

Expressions that may be executed in this function: IF, CASE, DECLARE, SET, RETURN

Parameters

	thd	thread context
[out]	nextp	next instruction pointer

Returns: false if success, true if error

◆ free_lex()

void sp_lex_instr::free_lex ( )

private

Cleanup and destroy assigned LEX-object if needed.

◆ get_expr_query()

virtual LEX_CSTRING sp_lex_instr::get_expr_query ( ) const

inlineprotectedvirtual

Returns: the expression query string. This string can not be passed directly to the parser as it is most likely not a valid SQL-statement.

Note: as it can be seen in the get_query() implementation, get_expr_query() might return EMPTY_CSTR. EMPTY_CSTR means that no query-expression is available. That happens when class provides different implementation of get_query(). Strictly speaking, this is a drawback of the current class hierarchy.

Reimplemented in sp_instr_set, sp_instr_set_trigger_field, sp_instr_freturn, and sp_lex_branch_instr.

◆ get_instr_trig_field_list()

SQL_I_List< Item_trigger_field > * sp_lex_instr::get_instr_trig_field_list ( )

inlineoverridevirtual

Reimplemented from sp_instr.

◆ get_query()

void sp_lex_instr::get_query ( String * sql_query ) const

protectedvirtual

Return the query string, which can be passed to the parser.

I.e. the operation should return a valid SQL-statement query string.

Parameters

[out] sql_query SQL-statement query string.

Reimplemented in sp_instr_stmt, and sp_instr_cpush.

◆ invalidate()

virtual void sp_lex_instr::invalidate ( )

protectedpure virtual

Invalidate the object.

Implemented in sp_instr_stmt, sp_instr_set, sp_instr_set_trigger_field, sp_instr_freturn, sp_lex_branch_instr, sp_instr_jump_case_when, and sp_instr_cpush.

◆ is_invalid()

virtual bool sp_lex_instr::is_invalid ( ) const

protectedpure virtual

Return values

false	if the object (i.e. LEX-object) is valid and exec_core() can be just called.
true	if the object is not valid any longer, exec_core() can not be called. The original query string should be re-parsed and a new LEX-object should be used.

Implemented in sp_instr_stmt, sp_instr_set, sp_instr_set_trigger_field, sp_instr_freturn, sp_lex_branch_instr, and sp_instr_cpush.

◆ on_after_expr_parsing()

virtual bool sp_lex_instr::on_after_expr_parsing ( THD * thd )

inlineprotectedvirtual

Callback function which is called after the statement query string is successfully parsed, and the thread context has not been switched to the outer context.

The thread context contains new LEX-object corresponding to the parsed query string.

Parameters

thd	Thread context.

Returns: Error flag.

Reimplemented in sp_instr_stmt, sp_instr_cpush, sp_instr_set, sp_instr_set_trigger_field, sp_instr_freturn, sp_instr_jump_if_not, sp_instr_set_case_expr, and sp_instr_jump_case_when.

◆ parse_statement()

LEX * sp_lex_instr::parse_statement	(	THD *	thd,
		sp_head *	sp
	)

private

Parse statement corresponding to this instruction and return a new LEX.

Parameters

thd	Thread context.
sp	The stored program.

Returns: new LEX-object or NULL in case of failure.

Move Item_trigger_field's list to instruction's Item_trigger_field list.

◆ reset_lex_and_exec_core()

bool sp_lex_instr::reset_lex_and_exec_core	(	THD *	thd,
		uint *	nextp,
		bool	open_tables
	)

private

Prepare LEX and thread for execution of instruction, if requested open and lock LEX's tables, execute instruction's core function, perform cleanup afterwards.

Parameters

	thd	thread context
[out]	nextp	next instruction pointer
	open_tables	if true then check read access to tables in LEX's table list and open and lock them (used in instructions which need to calculate some expression and don't execute complete statement).

Note: We are not saving/restoring some parts of THD which may need this because we do this once for whole routine execution in sp_head::execute().

Returns: Error status.

◆ set_lex()

void sp_lex_instr::set_lex	(	LEX *	lex,
		bool	is_lex_owner
	)

private

Set LEX-object.

Previously assigned LEX-object (if any) will be properly cleaned up and destroyed.

Parameters

lex	LEX-object to be used by this instance of sp_lex_instr.
is_lex_owner	the flag specifying if this instance sp_lex_instr owns (and thus deletes when needed) passed LEX-object.

◆ validate_lex_and_execute_core()

bool sp_lex_instr::validate_lex_and_execute_core	(	THD *	thd,
		uint *	nextp,
		bool	open_tables
	)

Make a few attempts to execute the instruction.

Basically, this operation does the following things:

install Reprepare_observer to catch metadata changes (if any);
calls reset_lex_and_exec_core() to execute the instruction;
if the execution fails due to a change in metadata, re-parse the instruction's SQL-statement and repeat execution.

Parameters

	thd	Thread context.
[out]	nextp	Next instruction pointer
	open_tables	Flag to specify if the function should check read access to tables in LEX's table list and open and lock them (used in instructions which need to calculate some expression and don't execute complete statement).

Returns: Error status.

Member Data Documentation

◆ m_first_execution

bool sp_lex_instr::m_first_execution

private

Indicates whether exec_core() has not been already called on the current LEX-object.

◆ m_is_lex_owner

bool sp_lex_instr::m_is_lex_owner

private

Indicates whether this sp_lex_instr instance is responsible for LEX-object deletion.

◆ m_lex

LEX* sp_lex_instr::m_lex

protected

LEX-object.

◆ m_lex_mem_root

MEM_ROOT sp_lex_instr::m_lex_mem_root {PSI_NOT_INSTRUMENTED, MEM_ROOT_BLOCK_SIZE}

private

Mem-root for storing the LEX-tree during reparse.

This mem-root is freed when a reparse is triggered or the stored routine is dropped.

◆ m_lex_query_tables_own_last

Table_ref** sp_lex_instr::m_lex_query_tables_own_last

private

The value m_lex->query_tables_own_last should be set to this when the statement enters/leaves prelocked mode on its own.

◆ m_prelocking_tables

Table_ref* sp_lex_instr::m_prelocking_tables

private

List of additional tables this statement needs to lock when it enters/leaves prelocked mode on its own.

◆ m_trig_field_list

SQL_I_List<Item_trigger_field> sp_lex_instr::m_trig_field_list

private

List of all the Item_trigger_field's of instruction.

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

sql/sp_instr.h
sql/sp_instr.cc

Public Member Functions

Protected Member Functions

Protected Attributes

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ sp_lex_instr()

◆ ~sp_lex_instr()

Member Function Documentation

◆ adjust_sql_command()

◆ cleanup_before_parsing()

◆ exec_core()

◆ execute()

◆ execute_expression()

◆ free_lex()

◆ get_expr_query()

◆ get_instr_trig_field_list()

◆ get_query()

◆ invalidate()

◆ is_invalid()

◆ on_after_expr_parsing()

◆ parse_statement()

◆ reset_lex_and_exec_core()

◆ set_lex()

◆ validate_lex_and_execute_core()

Member Data Documentation

◆ m_first_execution

◆ m_is_lex_owner

◆ m_lex

◆ m_lex_mem_root

◆ m_lex_query_tables_own_last

◆ m_prelocking_tables

◆ m_trig_field_list