sql_udf.cc File Reference

#include "sql/sql_udf.h"
#include <stdio.h>
#include <string.h>
#include <iterator>
#include <memory>
#include <new>
#include <string>
#include <unordered_map>
#include <utility>
#include "m_string.h"
#include "map_helpers.h"
#include "my_alloc.h"
#include "my_base.h"
#include "my_config.h"
#include "my_dbug.h"
#include "my_inttypes.h"
#include "my_io.h"
#include "my_macros.h"
#include "my_psi_config.h"
#include "my_sharedlib.h"
#include "my_sys.h"
#include "my_thread_local.h"
#include "mysql/components/service_implementation.h"
#include "mysql/components/services/bits/mysql_rwlock_bits.h"
#include "mysql/components/services/bits/psi_bits.h"
#include "mysql/components/services/bits/psi_memory_bits.h"
#include "mysql/components/services/bits/psi_rwlock_bits.h"
#include "mysql/components/services/log_builtins.h"
#include "mysql/components/services/log_shared.h"
#include "mysql/my_loglevel.h"
#include "mysql/psi/mysql_memory.h"
#include "mysql/psi/mysql_rwlock.h"
#include "mysql/strings/m_ctype.h"
#include "mysql_com.h"
#include "mysqld_error.h"
#include "nulls.h"
#include "sql/derror.h"
#include "sql/field.h"
#include "sql/handler.h"
#include "sql/iterators/row_iterator.h"
#include "sql/mdl.h"
#include "sql/mysqld.h"
#include "sql/sql_base.h"
#include "sql/sql_class.h"
#include "sql/sql_const.h"
#include "sql/sql_executor.h"
#include "sql/sql_parse.h"
#include "sql/sql_plugin.h"
#include "sql/sql_system_table_check.h"
#include "sql/sql_table.h"
#include "sql/table.h"
#include "sql/thd_raii.h"
#include "sql/thr_malloc.h"
#include "sql/transaction.h"
#include "string_with_len.h"
#include "strxnmov.h"
#include "thr_lock.h"
#include "udf_registration_imp.h"
#include <dlfcn.h>

Functions
static udf_func *	add_udf (LEX_STRING *name, Item_result ret, char *dl, Item_udftype typ)
static void	udf_hash_delete (udf_func *udf)
	Delete the UDF function from the UDF hash. More...
static void *	find_udf_dl (const char *dl)
static char *	init_syms (udf_func *tmp, char *nm)
static void	init_udf_psi_keys (void)
void	udf_init_globals ()
	Initialize the UDF global structures. More...
void	udf_read_functions_table ()
void	udf_unload_udfs ()
	Deinitialize the UDF subsystem. More...
void	udf_deinit_globals ()
	Deinitialize the UDF subsystem. More...
void	free_udf (udf_func *udf)
udf_func *	find_udf (const char *name, size_t length, bool mark_used)
static bool	udf_end_transaction (THD *thd, bool rollback, udf_func *udf, bool insert_udf)
	Commit or rollback a transaction. More...
bool	mysql_create_function (THD *thd, udf_func *udf, bool if_not_exists)
	Create a user defined function. More...
bool	mysql_drop_function (THD *thd, const LEX_STRING *udf_name)
	Drop a user defined function. More...
void	udf_hash_rlock (void)
void	udf_hash_unlock (void)
ulong	udf_hash_size (void)
void	udf_hash_for_each (udf_hash_for_each_func_t *func, void *arg)

Variables
static bool	initialized = false
	A local flag indicating whether SQL based UDF operations are allowed. More...
static MEM_ROOT	mem
static collation_unordered_map< std::string, udf_func * > *	udf_hash
static mysql_rwlock_t	THR_LOCK_udf
static constexpr const size_t	UDF_ALLOC_BLOCK_SIZE {1024}
static const int	MYSQL_UDF_TABLE_FIELD_COUNT = 4
static const TABLE_FIELD_TYPE	mysql_udf_table_fields [MYSQL_UDF_TABLE_FIELD_COUNT]
static const TABLE_FIELD_DEF	mysql_udf_table_def
static PSI_memory_key	key_memory_udf_mem
static PSI_rwlock_key	key_rwlock_THR_LOCK_udf
static PSI_rwlock_info	all_udf_rwlocks []
static PSI_memory_info	all_udf_memory []

Function Documentation

add_udf()

static udf_func * add_udf ( LEX_STRING *  name, Item_result  ret, char *  dl, Item_udftype  typ  )

static

find_udf()

udf_func * find_udf	(	const char *	name,
		size_t	length,
		bool	mark_used
	)

find_udf_dl()

static void * find_udf_dl ( const char *  dl )

static

free_udf()

void free_udf

(

udf_func *

udf

)

init_syms()

static char * init_syms ( udf_func *  tmp, char *  nm  )

static

init_udf_psi_keys()

static void init_udf_psi_keys ( void  )

static

mysql_create_function()

bool mysql_create_function	(	THD *	thd,
		udf_func *	udf,
		bool	if_not_exists
	)

Create a user defined function.

Atomicity: The operation to create a user defined function is atomic/crash-safe. Changes to the Data-dictionary and writing event to binlog are part of the same transaction. All the changes are done as part of the same transaction or do not have any side effects on the operation failure. UDF hash is in sync with operation state. UDF hash do not contain any stale/incorrect data in case of failure. In case of crash, there won't be any discrepancy between the data-dictionary table and the binary log.

Parameters

thd	THD context.
udf	Pointer to UDF function.
if_not_exists	True if 'IF NOT EXISTS' clause was specified.

Note

Like implementations of other DDL/DML in MySQL, this function relies on the caller to close the thread tables. This is done in the end of dispatch_command().

mysql_drop_function()

bool mysql_drop_function	(	THD *	thd,
		const LEX_STRING *	udf_name
	)

Drop a user defined function.

Atomicity: The operation to drop a user defined function is atomic/crash-safe. Changes to the Data-dictionary and writing event to binlog are part of the same transaction. All the changes are done as part of the same transaction or do not have any side effects on the operation failure. UDF hash is in sync with operation state. UDF hash do not contain any stale/incorrect data in case of failure. In case of crash, there won't be any discrepancy between the data-dictionary table and the binary log.

Parameters

thd	THD context.
udf_name	Name of the UDF function.

udf_deinit_globals()

void udf_deinit_globals

(

)

Deinitialize the UDF subsystem.

This function does the following:

1. Free the UDF hash.
2. Free the memroot allocated.
3. Destroy the RW mutex object.

udf_end_transaction()

static bool udf_end_transaction ( THD *  thd, bool  rollback, udf_func *  udf, bool  insert_udf  )

static

Commit or rollback a transaction.

Also close tables which it has opened and release metadata locks. Add/Remove from the in-memory hash depending on transaction commit or rollback and the bool flag passed to this function.

Parameters

thd	THD context.
rollback	Rollback transaction if true.
udf	Pointer to UDF function.
insert_udf	Insert UDF in hash if true.

Return values

False	- Success.
True	- Error.

udf_hash_delete()

static void udf_hash_delete ( udf_func *  udf )

static

Delete the UDF function from the UDF hash.

Parameters

udf	Pointer to the UDF function.

Note

The function remove the udf function from the udf hash if it is not in use. If the function is in use, the function name is renamed so that it is not used. The function shall be removed when no threads use it.

udf_hash_for_each()

void udf_hash_for_each	(	udf_hash_for_each_func_t *	func,
		void *	arg
	)

udf_hash_rlock()

void udf_hash_rlock

(

void

)

udf_hash_size()

ulong udf_hash_size

(

void

)

udf_hash_unlock()

void udf_hash_unlock

(

void

)

udf_init_globals()

void udf_init_globals

(

)

Initialize the UDF global structures.

This is done as a separate step so that the UDF registration service can work when initializing plugins, which happens before reading the UDF table.

udf_read_functions_table()

void udf_read_functions_table

(

)

udf_unload_udfs()

void udf_unload_udfs

(

)

Deinitialize the UDF subsystem.

This function closes the shared libraries.

Variable Documentation

all_udf_memory

PSI_memory_info all_udf_memory[]

static

Initial value:

= {{&key_memory_udf_mem, "udf_mem",
                                            PSI_FLAG_ONLY_GLOBAL_STAT, 0,
                                            "Shared structure of UDFs."}}

all_udf_rwlocks

PSI_rwlock_info all_udf_rwlocks[]

static

Initial value:

= {{&key_rwlock_THR_LOCK_udf,
                                             "THR_LOCK_udf", PSI_FLAG_SINGLETON,
                                             0, PSI_DOCUMENT_ME}}

initialized

bool initialized = false

static

A local flag indicating whether SQL based UDF operations are allowed.

Now the UDF structures are always allocated/deallocated due to the component service.

So this variable does not cover initialization/deinitialization of these. mem and THR_LOCK_udf are always initialized, even in –skip-grant-tables mode.

key_memory_udf_mem

PSI_memory_key key_memory_udf_mem

static

key_rwlock_THR_LOCK_udf

PSI_rwlock_key key_rwlock_THR_LOCK_udf

static

mem

MEM_ROOT mem

static

mysql_udf_table_def

const TABLE_FIELD_DEF mysql_udf_table_def

static

Initial value:

= {MYSQL_UDF_TABLE_FIELD_COUNT,
                                                    mysql_udf_table_fields}

MYSQL_UDF_TABLE_FIELD_COUNT

const int MYSQL_UDF_TABLE_FIELD_COUNT = 4

static

mysql_udf_table_fields

const TABLE_FIELD_TYPE mysql_udf_table_fields[MYSQL_UDF_TABLE_FIELD_COUNT]

static

Initial value:

= {
        {{STRING_WITH_LEN("name")},
         {STRING_WITH_LEN("char(64)")},
         {nullptr, 0}},
        {{STRING_WITH_LEN("ret")}, {STRING_WITH_LEN("tinyint")}, {nullptr, 0}},
        {{STRING_WITH_LEN("dl")}, {STRING_WITH_LEN("char(128)")}, {nullptr, 0}},
        {{STRING_WITH_LEN("type")},
         {STRING_WITH_LEN("enum('function','aggregate')")},
         {STRING_WITH_LEN("utf8mb3")}}}

THR_LOCK_udf

mysql_rwlock_t THR_LOCK_udf

static

UDF_ALLOC_BLOCK_SIZE

constexpr const size_t UDF_ALLOC_BLOCK_SIZE {1024}

staticconstexpr

udf_hash

collation_unordered_map<std::string, udf_func *>* udf_hash

static