item_func.cc File Reference

This file defines all numerical Items. More...

#include "sql/item_func.h"
#include <algorithm>
#include <atomic>
#include <bit>
#include <cfloat>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ctime>
#include <initializer_list>
#include <iosfwd>
#include <limits>
#include <memory>
#include <new>
#include <string>
#include <type_traits>
#include <unordered_map>
#include <utility>
#include "integer_digits.h"
#include "m_string.h"
#include "map_helpers.h"
#include "mutex_lock.h"
#include "my_bitmap.h"
#include "my_byteorder.h"
#include "my_dbug.h"
#include "my_double2ulonglong.h"
#include "my_hostname.h"
#include "my_psi_config.h"
#include "my_rnd.h"
#include "my_sqlcommand.h"
#include "my_sys.h"
#include "my_systime.h"
#include "my_thread.h"
#include "my_user.h"
#include "mysql/components/services/bits/mysql_cond_bits.h"
#include "mysql/components/services/bits/mysql_mutex_bits.h"
#include "mysql/components/services/bits/psi_bits.h"
#include "mysql/components/services/bits/psi_mutex_bits.h"
#include "mysql/components/services/log_builtins.h"
#include "mysql/components/services/log_shared.h"
#include "mysql/my_loglevel.h"
#include "mysql/mysql_lex_string.h"
#include "mysql/plugin_audit.h"
#include "mysql/psi/mysql_cond.h"
#include "mysql/psi/mysql_mutex.h"
#include "mysql/service_mysql_password_policy.h"
#include "mysql/service_thd_wait.h"
#include "mysql/status_var.h"
#include "mysql/strings/dtoa.h"
#include "mysql/strings/int2str.h"
#include "mysql/strings/m_ctype.h"
#include "mysql/strings/my_strtoll10.h"
#include "prealloced_array.h"
#include "sql-common/json_dom.h"
#include "sql/auth/auth_acls.h"
#include "sql/auth/auth_common.h"
#include "sql/auth/sql_security_ctx.h"
#include "sql/binlog.h"
#include "sql/check_stack.h"
#include "sql/current_thd.h"
#include "sql/dd/info_schema/table_stats.h"
#include "sql/dd/info_schema/tablespace_stats.h"
#include "sql/dd/object_id.h"
#include "sql/dd/properties.h"
#include "sql/dd/types/abstract_table.h"
#include "sql/dd/types/column.h"
#include "sql/dd/types/index.h"
#include "sql/dd_sql_view.h"
#include "sql/dd_table_share.h"
#include "sql/debug_sync.h"
#include "sql/derror.h"
#include "sql/error_handler.h"
#include "sql/item.h"
#include "sql/item_cmpfunc.h"
#include "sql/item_json_func.h"
#include "sql/item_strfunc.h"
#include "sql/item_subselect.h"
#include "sql/key.h"
#include "sql/log_event.h"
#include "sql/mdl.h"
#include "sql/mysqld.h"
#include "sql/parse_tree_helpers.h"
#include "sql/parse_tree_node_base.h"
#include "sql/protocol.h"
#include "sql/psi_memory_key.h"
#include "sql/resourcegroups/resource_group.h"
#include "sql/resourcegroups/resource_group_basic_types.h"
#include "sql/resourcegroups/resource_group_mgr.h"
#include "sql/rpl_gtid.h"
#include "sql/rpl_mi.h"
#include "sql/rpl_msr.h"
#include "sql/rpl_rli.h"
#include "sql/sp.h"
#include "sql/sp_head.h"
#include "sql/sp_pcontext.h"
#include "sql/sql_array.h"
#include "sql/sql_audit.h"
#include "sql/sql_base.h"
#include "sql/sql_bitmap.h"
#include "sql/sql_class.h"
#include "sql/sql_cmd.h"
#include "sql/sql_derived.h"
#include "sql/sql_error.h"
#include "sql/sql_exchange.h"
#include "sql/sql_executor.h"
#include "sql/sql_lex.h"
#include "sql/sql_list.h"
#include "sql/sql_load.h"
#include "sql/sql_optimizer.h"
#include "sql/sql_parse.h"
#include "sql/sql_show.h"
#include "sql/sql_time.h"
#include "sql/strfunc.h"
#include "sql/system_variables.h"
#include "sql/thd_raii.h"
#include "sql/val_int_compare.h"
#include "sql_string.h"
#include "storage/perfschema/terminology_use_previous_enum.h"
#include "string_with_len.h"
#include "template_utils.h"
#include "thr_mutex.h"
#include "vector-common/vector_constants.h"

Classes
class	THD_in_loadable_function_handler
class	Interruptible_wait
	Enables a session to wait on a condition until a timeout or a network disconnect occurs. More...
struct	User_level_lock
	For locks with EXPLICIT duration, MDL returns a new ticket every time a lock is granted. More...
class	User_level_lock_wait_error_handler
	When MDL detects a lock wait timeout, it pushes an error into the statement diagnostics area. More...
class	MDL_lock_get_owner_thread_id_visitor

Functions
static void	free_user_var (user_var_entry *entry)
static int	get_var_with_binlog (THD *thd, enum_sql_command sql_command, const Name_string &name, user_var_entry **out_entry)
	Get variable by name and, if necessary, put the record of variable use into the binary log. More...
bool	check_reserved_words (const char *name)
void	report_conversion_error (const CHARSET_INFO *to_cs, const char *from, size_t from_length, const CHARSET_INFO *from_cs)
bool	simplify_string_args (THD *thd, const DTCollation &c, Item **args, uint nargs)
	Simplify the string arguments to a function, if possible. More...
String *	eval_string_arg_noinline (const CHARSET_INFO *to_cs, Item *arg, String *buffer)
	Evaluate an argument string and return it in the desired character set. More...
bool	eval_const_cond (THD *thd, Item *cond, bool *value)
	Evaluate a constant condition, represented by an Item tree. More...
static bool	test_if_sum_overflows_ull (ulonglong arg1, ulonglong arg2)
	Test if the sum of arguments overflows the ulonglong range. More...
bool	param_type_uses_non_param_inner (THD *thd, uint arg_count, Item **args, enum_field_types def)
	For arguments of this Item_func ("args" array), all of them: find an argument that is not a dynamic parameter; if found, all dynamic parameters without a valid type get the type of this; if not found, they get type "def". More...
bool	is_function_of_type (const Item *item, Item_func::Functype type)
	Checks if "item" is a function of the specified type. More...
bool	contains_function_of_type (Item *item, Item_func::Functype type)
	Checks if "item" contains a function of the specified type. More...
Item_field *	get_gc_for_expr (const Item *func, Field *fld, Item_result type, Field **found)
	Return new Item_field if given expression matches GC. More...
static bool	substitute_gc_expression (Item **expr, Item **value, List< Field > *gc_fields, Item_result type, Item_func *predicate)
	Attempt to substitute an expression with an equivalent generated column in a predicate. More...
static void	gc_subst_overlaps_contains (Item **func, Item **vals, Json_wrapper &vals_wr, List< Field > *gc_fields)
	A helper function for Item_func::gc_subst_transformer, that tries to substitute the given JSON_CONTAINS or JSON_OVERLAPS function for one of GCs from the provided list. More...
void	unsupported_json_comparison (size_t arg_count, Item **args, const char *msg)
	Go through the arguments of a function and check if any of them are JSON. More...
static longlong	val_int_from_str (Item *item, bool unsigned_flag, bool *null_value)
template longlong	Item_func_bit_two_param::eval_int_op< std::bit_or< ulonglong > > (std::bit_or< ulonglong >)
	Instantiations of the above. More...
template longlong	Item_func_bit_two_param::eval_int_op< std::bit_and< ulonglong > > (std::bit_and< ulonglong >)
template longlong	Item_func_bit_two_param::eval_int_op< std::bit_xor< ulonglong > > (std::bit_xor< ulonglong >)
double	my_double_round (double value, longlong dec, bool dec_unsigned, bool truncate)
static ulonglong	my_unsigned_round (ulonglong value, ulonglong to, bool *round_overflow)
static int	temporal_rank (enum_field_types type)
void	mysql_ull_cleanup (THD *thd)
	Release all user level locks for this THD. More...
void	mysql_ull_set_explicit_lock_duration (THD *thd)
	Set explicit duration for metadata locks corresponding to user level locks to protect them from being released at the end of transaction. More...
static bool	check_and_convert_ull_name (char *buff, const String *org_name)
	Helper function which checks if user-level lock name is acceptable and converts it to system charset (utf8). More...
static void	init_item_func_sleep_psi_keys ()
void	item_func_sleep_init ()
void	item_func_sleep_free ()
static user_var_entry *	get_variable (THD *thd, const Name_string &name, const CHARSET_INFO *cs)
	Get variable with given name; conditionally create it if non-existing. More...
static void	update_table_read_set (const Field *field)
	Add field into table read set. More...
Item *	get_system_variable (Parse_context *pc, enum_var_type scope, const LEX_CSTRING &prefix, const LEX_CSTRING &suffix, bool unsafe_for_replication)
	Return value of an system variable base[.name] as a constant item. More...
static void	my_missing_function_error (const LEX_STRING &token, const char *func_name)
void	uuid_short_init ()
static bool	is_hidden_by_ndb (THD *thd, String *schema_name, String *table_name)
	Check if schema and table are hidden by NDB engine. More...
static bool	check_table_and_trigger_access (Item **args, bool check_trigger_acl, bool *null_value)
static ulonglong	get_table_statistics (Item **args, uint arg_count, dd::info_schema::enum_table_stats_type stype, bool *null_value)
	Get table statistics from dd::info_schema::get_table_statistics. More...
void	retrieve_tablespace_statistics (THD *thd, Item **args, bool *null_value)
	Retrieve tablespace statistics from SE. More...

Variables
static const char	separator = ','
mysql_mutex_t	LOCK_item_func_sleep
	Lock which is used to implement interruptible wait for SLEEP() function. More...
static PSI_mutex_key	key_LOCK_item_func_sleep
static PSI_mutex_info	item_func_sleep_mutexes []
static bool	item_func_sleep_inited = false
ulonglong	uuid_value

Detailed Description

This file defines all numerical Items.

Function Documentation

check_and_convert_ull_name()

static bool check_and_convert_ull_name ( char *  buff, const String *  org_name  )

static

Helper function which checks if user-level lock name is acceptable and converts it to system charset (utf8).

Error is emitted if name is not acceptable. Name is also lowercased to ensure that user-level lock names are treated in case-insensitive fashion even though MDL subsystem which used by implementation does binary comparison of keys.

Parameters

buff	Buffer for lowercased name in system charset of NAME_LEN + 1 bytes length.
org_name	Original string passed as name parameter to user-level lock function.

Returns

True in case of error, false on success.

check_reserved_words()

bool check_reserved_words

(

const char *

name

)

check_table_and_trigger_access()

static bool check_table_and_trigger_access ( Item **  args, bool  check_trigger_acl, bool *  null_value  )

static

contains_function_of_type()

bool contains_function_of_type	(	Item *	item,
		Item_func::Functype	type
	)

Checks if "item" contains a function of the specified type.

eval_const_cond()

bool eval_const_cond	(	THD *	thd,
		Item *	cond,
		bool *	value
	)

Evaluate a constant condition, represented by an Item tree.

Parameters

	thd	Thread handler
	cond	The constant condition to evaluate
[out]	value	Returned value, either true or false

Returns

false if evaluation is successful, true otherwise

eval_string_arg_noinline()

String * eval_string_arg_noinline	(	const CHARSET_INFO *	to_cs,
		Item *	arg,
		String *	buffer
	)

Evaluate an argument string and return it in the desired character set.

Perform character set conversion if needed. Perform character set validation (from a binary string) if needed.

Parameters

to_cs	The desired character set
arg	Argument to evaluate as a string value
buffer	String buffer where argument is evaluated, if necessary

Returns

string pointer if success, NULL if error or NULL value

free_user_var()

static void free_user_var ( user_var_entry *  entry )

static

gc_subst_overlaps_contains()

static void gc_subst_overlaps_contains ( Item **  func, Item **  vals, Json_wrapper &  vals_wr, List< Field > *  gc_fields  )

static

A helper function for Item_func::gc_subst_transformer, that tries to substitute the given JSON_CONTAINS or JSON_OVERLAPS function for one of GCs from the provided list.

The function checks whether there's an index with matching expression and whether all scalars for lookup can be coerced to index's GC field without errors. If so, index's GC field substitutes the given function, args are replaced for array of coerced values in order to match GC's type. substitute_gc_expression() can't be used to these functions as it's tailored to handle regular single-valued indexes and doesn't ensure correct coercion of all values to lookup in multi-valued index.

Parameters

func	Function to replace
vals	Args to replace
vals_wr	Json_wrapper containing array of values for index lookup
gc_fields	List of generated fields to look the function's substitute in

get_gc_for_expr()

Item_field * get_gc_for_expr	(	const Item *	func,
		Field *	fld,
		Item_result	type,
		Field **	found
	)

Return new Item_field if given expression matches GC.

See also

substitute_gc()

Parameters

	func	Expression to be replaced
	fld	GCs field
	type	Result type to match with Field
[out]	found	If given, just return found field, without Item_field

Returns

item new Item_field for matched GC NULL otherwise

get_system_variable()

Item * get_system_variable	(	Parse_context *	pc,
		enum_var_type	scope,
		const LEX_CSTRING &	prefix,
		const LEX_CSTRING &	suffix,
		bool	unsafe_for_replication
	)

Return value of an system variable base[.name] as a constant item.

Create new Item_func_get_system_var object.

Parameters

pc	Current parse context
scope	Global / session
prefix	Optional prefix part of the variable name
suffix	Trivial name of suffix part of the variable name
unsafe_for_replication	If true and if the variable is written to a binlog then mark the statement as unsafe.

Note

If component.str = 0 then the variable name is in 'name'

Returns

• 0 : error
• # : constant item

get_table_statistics()

static ulonglong get_table_statistics ( Item **  args, uint  arg_count, dd::info_schema::enum_table_stats_type  stype, bool *  null_value  )

static

Get table statistics from dd::info_schema::get_table_statistics.

Parameters

	args	List of parameters in following order, - Schema_name - Table_name - Engine_name - se_private_id - Hidden_table - Tablespace_se_private_data - Table_se_private_data (Used if stype is AUTO_INC) - Partition name (optional argument).
	arg_count	Number of arguments in 'args'
	stype	Type of statistics that is requested
[out]	null_value	Marked true indicating NULL, if there is no value.

Returns

ulonglong representing the statistics requested.

get_var_with_binlog()

static int get_var_with_binlog ( THD *  thd, enum_sql_command  sql_command, const Name_string &  name, user_var_entry **  out_entry  )

static

Get variable by name and, if necessary, put the record of variable use into the binary log.

When a user variable is invoked from an update query (INSERT, UPDATE etc), stores this variable and its value in thd->user_var_events, so that it can be written to the binlog (will be written just before the query is written, see log.cc).

Parameters

	thd	Current session.
	sql_command	The command the variable participates in.
	name	Variable name
[out]	out_entry	variable structure or NULL. The pointer is set regardless of whether function succeeded or not.

Return values

0	OK
1	Failed to put appropriate record into binary log

get_variable()

static user_var_entry * get_variable ( THD *  thd, const Name_string &  name, const CHARSET_INFO *  cs  )

static

Get variable with given name; conditionally create it if non-existing.

Parameters

thd	thread context
name	name of user variable
cs	character set; = NULL: Do not create variable if non-existing. != NULL: Create variable with this character set.

Returns

pointer to variable entry. = NULL: variable does not exist (if cs == NULL), or could not create variable (if cs != NULL)

init_item_func_sleep_psi_keys()

static void init_item_func_sleep_psi_keys ( )

static

is_function_of_type()

bool is_function_of_type	(	const Item *	item,
		Item_func::Functype	type
	)

Checks if "item" is a function of the specified type.

is_hidden_by_ndb()

static bool is_hidden_by_ndb ( THD *  thd, String *  schema_name, String *  table_name  )

inlinestatic

Check if schema and table are hidden by NDB engine.

Parameters

thd	Thread handle.
schema_name	Schema name.
table_name	Table name.

Return values

true	If schema and table are hidden by NDB.
false	If schema and table are not hidden by NDB.

Item_func_bit_two_param::eval_int_op< std::bit_and< ulonglong > >()

template longlong Item_func_bit_two_param::eval_int_op< std::bit_and< ulonglong > >

(

std::bit_and< ulonglong >

)

Item_func_bit_two_param::eval_int_op< std::bit_or< ulonglong > >()

template longlong Item_func_bit_two_param::eval_int_op< std::bit_or< ulonglong > >

(

std::bit_or< ulonglong >

)

Instantiations of the above.

Item_func_bit_two_param::eval_int_op< std::bit_xor< ulonglong > >()

template longlong Item_func_bit_two_param::eval_int_op< std::bit_xor< ulonglong > >

(

std::bit_xor< ulonglong >

)

item_func_sleep_free()

void item_func_sleep_free

(

)

item_func_sleep_init()

void item_func_sleep_init

(

)

my_double_round()

double my_double_round	(	double	value,
		longlong	dec,
		bool	dec_unsigned,
		bool	truncate
	)

my_missing_function_error()

static void my_missing_function_error ( const LEX_STRING &  token, const char *  func_name  )

static

my_unsigned_round()

static ulonglong my_unsigned_round ( ulonglong  value, ulonglong  to, bool *  round_overflow  )

inlinestatic

mysql_ull_cleanup()

void mysql_ull_cleanup

(

THD *

thd

)

Release all user level locks for this THD.

mysql_ull_set_explicit_lock_duration()

void mysql_ull_set_explicit_lock_duration

(

THD *

thd

)

Set explicit duration for metadata locks corresponding to user level locks to protect them from being released at the end of transaction.

param_type_uses_non_param_inner()

bool param_type_uses_non_param_inner ( THD *  thd, uint  arg_count, Item **  args, enum_field_types  def  )

inline

For arguments of this Item_func ("args" array), all of them: find an argument that is not a dynamic parameter; if found, all dynamic parameters without a valid type get the type of this; if not found, they get type "def".

Parameters

thd	thread handler
arg_count	number of arguments to check
args	array of arguments, size 'arg_count'
def	default type

Returns

false if success, true if error

report_conversion_error()

void report_conversion_error	(	const CHARSET_INFO *	to_cs,
		const char *	from,
		size_t	from_length,
		const CHARSET_INFO *	from_cs
	)

retrieve_tablespace_statistics()

void retrieve_tablespace_statistics	(	THD *	thd,
		Item **	args,
		bool *	null_value
	)

Retrieve tablespace statistics from SE.

Parameters

	thd	The current thread.
	args	List of parameters in following order, - Tablespace_name - Engine_name - Tablespace_se_private_data
[out]	null_value	Marked true indicating NULL, if there is no value.

simplify_string_args()

bool simplify_string_args	(	THD *	thd,
		const DTCollation &	c,
		Item **	args,
		uint	nargs
	)

Simplify the string arguments to a function, if possible.

Currently used to substitute const values with character strings in the desired character set. Only used during resolving.

Parameters

thd	thread handler
c	Desired character set and collation
args	Pointer to argument array
nargs	Number of arguments to process

Returns

false if success, true if error

substitute_gc_expression()

static bool substitute_gc_expression ( Item **  expr, Item **  value, List< Field > *  gc_fields, Item_result  type, Item_func *  predicate  )

static

Attempt to substitute an expression with an equivalent generated column in a predicate.

Parameters

expr	the expression that should be substituted
value	if given, value will be coerced to GC field's type and the result will substitute the original value. Used by multi-valued index.
gc_fields	list of indexed generated columns to check for equivalence with the expression
type	the acceptable type of the generated column that replaces the expression
predicate	the predicate in which the substitution is done

Returns

true on error, false on success

temporal_rank()

static int temporal_rank ( enum_field_types  type )

static

test_if_sum_overflows_ull()

static bool test_if_sum_overflows_ull ( ulonglong  arg1, ulonglong  arg2  )

inlinestatic

Test if the sum of arguments overflows the ulonglong range.

unsupported_json_comparison()

void unsupported_json_comparison	(	size_t	arg_count,
		Item **	args,
		const char *	msg
	)

Go through the arguments of a function and check if any of them are JSON.

If a JSON argument is found, raise a warning saying that this operation is not supported yet. This function is used to notify users that they are comparing JSON values using a mechanism that has not yet been updated to use the JSON comparator. JSON values are typically handled as strings in that case.

Parameters

arg_count	the number of arguments
args	the arguments to go through looking for JSON values
msg	the message that explains what is not supported

update_table_read_set()

static void update_table_read_set ( const Field *  field )

static

Add field into table read set.

Parameters

field

field to be added to the table read set.

uuid_short_init()

void uuid_short_init

(

)

val_int_from_str()

static longlong val_int_from_str ( Item *  item, bool  unsigned_flag, bool *  null_value  )

static

Variable Documentation

item_func_sleep_inited

bool item_func_sleep_inited = false

static

item_func_sleep_mutexes

PSI_mutex_info item_func_sleep_mutexes[]

static

Initial value:

= {
    {&key_LOCK_item_func_sleep, "LOCK_item_func_sleep", PSI_FLAG_SINGLETON, 0,
     PSI_DOCUMENT_ME}}

key_LOCK_item_func_sleep

PSI_mutex_key key_LOCK_item_func_sleep

static

LOCK_item_func_sleep

mysql_mutex_t LOCK_item_func_sleep

Lock which is used to implement interruptible wait for SLEEP() function.

separator

const char separator = ','

static

uuid_value

ulonglong uuid_value