path: root/storage/innobase/include/dict0mem.h

/******************************************************
Data dictionary memory object creation

(c) 1996 Innobase Oy

Created 1/8/1996 Heikki Tuuri
*******************************************************/

#ifndef dict0mem_h
#define dict0mem_h

#include "univ.i"
#include "dict0types.h"
#include "data0type.h"
#include "data0data.h"
#include "mem0mem.h"
#include "rem0types.h"
#include "btr0types.h"
#include "ut0mem.h"
#include "ut0lst.h"
#include "ut0rnd.h"
#include "ut0byte.h"
#include "sync0rw.h"
#include "lock0types.h"
#include "hash0hash.h"
#include "que0types.h"

/* Type flags of an index: OR'ing of the flags is allowed to define a
combination of types */
#define DICT_CLUSTERED	1	/* clustered index */
#define DICT_UNIQUE	2	/* unique index */
#define	DICT_UNIVERSAL	4	/* index which can contain records from any
				other index */
#define	DICT_IBUF	8	/* insert buffer tree */

/* Types for a table object */
#define DICT_TABLE_ORDINARY		1
#if 0 /* not implemented */
#define	DICT_TABLE_CLUSTER_MEMBER	2
#define	DICT_TABLE_CLUSTER		3 /* this means that the table is
					  really a cluster definition */
#endif

/* Table flags */
#define DICT_TF_COMPACT			1	/* compact page format */

/**************************************************************************
Creates a table memory object. */

dict_table_t*
dict_mem_table_create(
/*==================*/
					/* out, own: table object */
	const char*	name,		/* in: table name */
	ulint		space,		/* in: space where the clustered index
					of the table is placed; this parameter
					is ignored if the table is made
					a member of a cluster */
	ulint		n_cols,		/* in: number of columns */
	ulint		flags);		/* in: table flags */
/********************************************************************
Free a table memory object. */

void
dict_mem_table_free(
/*================*/
	dict_table_t*	table);		/* in: table */
/**************************************************************************
Adds a column definition to a table. */

void
dict_mem_table_add_col(
/*===================*/
	dict_table_t*	table,	/* in: table */
	mem_heap_t*	heap,	/* in: temporary memory heap, or NULL */
	const char*	name,	/* in: column name, or NULL */
	ulint		mtype,	/* in: main datatype */
	ulint		prtype,	/* in: precise type */
	ulint		len);	/* in: precision */
/**************************************************************************
Creates an index memory object. */

dict_index_t*
dict_mem_index_create(
/*==================*/
					/* out, own: index object */
	const char*	table_name,	/* in: table name */
	const char*	index_name,	/* in: index name */
	ulint		space,		/* in: space where the index tree is
					placed, ignored if the index is of
					the clustered type */
	ulint		type,		/* in: DICT_UNIQUE,
					DICT_CLUSTERED, ... ORed */
	ulint		n_fields);	/* in: number of fields */
/**************************************************************************
Adds a field definition to an index. NOTE: does not take a copy
of the column name if the field is a column. The memory occupied
by the column name may be released only after publishing the index. */

void
dict_mem_index_add_field(
/*=====================*/
	dict_index_t*	index,		/* in: index */
	const char*	name,		/* in: column name */
	ulint		prefix_len);	/* in: 0 or the column prefix length
					in a MySQL index like
					INDEX (textcol(25)) */
/**************************************************************************
Frees an index memory object. */

void
dict_mem_index_free(
/*================*/
	dict_index_t*	index);	/* in: index */
/**************************************************************************
Creates and initializes a foreign constraint memory object. */

dict_foreign_t*
dict_mem_foreign_create(void);
/*=========================*/
				/* out, own: foreign constraint struct */

/* Data structure for a column in a table */
struct dict_col_struct{
	/*----------------------*/
	/* The following are copied from dtype_t,
	so that all bit-fields can be packed tightly. */
	unsigned	mtype:8;	/* main data type */
	unsigned	prtype:24;	/* precise type; MySQL data
					type, charset code, flags to
					indicate nullability,
					signedness, whether this is a
					binary string, whether this is
					a true VARCHAR where MySQL
					uses 2 bytes to store the length */

	/* the remaining fields do not affect alphabetical ordering: */

	unsigned	len:16;		/* length; for MySQL data this
					is field->pack_length(),
					except that for a >= 5.0.3
					type true VARCHAR this is the
					maximum byte length of the
					string data (in addition to
					the string, MySQL uses 1 or 2
					bytes to store the string length) */

	unsigned	mbminlen:2;	/* minimum length of a
					character, in bytes */
	unsigned	mbmaxlen:3;	/* maximum length of a
					character, in bytes */
	/*----------------------*/
	/* End of definitions copied from dtype_t */

	unsigned	ind:10;		/* table column position
					(starting from 0) */
	unsigned	ord_part:1;	/* nonzero if this column
					appears in the ordering fields
					of an index */
};

/* DICT_MAX_INDEX_COL_LEN is measured in bytes and is the maximum
indexed column length (or indexed prefix length). It is set to 3*256,
so that one can create a column prefix index on 256 characters of a
TEXT or VARCHAR column also in the UTF-8 charset. In that charset,
a character may take at most 3 bytes.
This constant MUST NOT BE CHANGED, or the compatibility of InnoDB data
files would be at risk! */

#define DICT_MAX_INDEX_COL_LEN		768

/* Data structure for a field in an index */
struct dict_field_struct{
	dict_col_t*	col;		/* pointer to the table column */
	const char*	name;		/* name of the column */
	unsigned	prefix_len:10;	/* 0 or the length of the column
					prefix in bytes in a MySQL index of
					type, e.g., INDEX (textcol(25));
					must be smaller than
					DICT_MAX_INDEX_COL_LEN; NOTE that
					in the UTF-8 charset, MySQL sets this
					to 3 * the prefix len in UTF-8 chars */
	unsigned	fixed_len:10;	/* 0 or the fixed length of the
					column if smaller than
					DICT_MAX_INDEX_COL_LEN */
};

/* Data structure for an index */
struct dict_index_struct{
	dulint		id;	/* id of the index */
	mem_heap_t*	heap;	/* memory heap */
	ulint		type;	/* index type */
	const char*	name;	/* index name */
	const char*	table_name; /* table name */
	dict_table_t*	table;	/* back pointer to table */
	unsigned	space:32;
				/* space where the index tree is placed */
	unsigned	page:32;/* index tree root page number */
	unsigned	trx_id_offset:10;/* position of the the trx id column
				in a clustered index record, if the fields
				before it are known to be of a fixed size,
				0 otherwise */
	unsigned	n_user_defined_cols:10;
				/* number of columns the user defined to
				be in the index: in the internal
				representation we add more columns */
	unsigned	n_uniq:10;/* number of fields from the beginning
				which are enough to determine an index
				entry uniquely */
	unsigned	n_def:10;/* number of fields defined so far */
	unsigned	n_fields:10;/* number of fields in the index */
	unsigned	n_nullable:10;/* number of nullable fields */
	unsigned	cached:1;/* TRUE if the index object is in the
				dictionary cache */
	dict_field_t*	fields;	/* array of field descriptions */
	UT_LIST_NODE_T(dict_index_t)
			indexes;/* list of indexes of the table */
	btr_search_t*	search_info; /* info used in optimistic searches */
	/*----------------------*/
	ib_longlong*	stat_n_diff_key_vals;
				/* approximate number of different key values
				for this index, for each n-column prefix
				where n <= dict_get_n_unique(index); we
				periodically calculate new estimates */
	ulint		stat_index_size;
				/* approximate index size in database pages */
	ulint		stat_n_leaf_pages;
				/* approximate number of leaf pages in the
				index tree */
	rw_lock_t	lock;	/* read-write lock protecting the upper levels
				of the index tree */
#ifdef UNIV_DEBUG
	ulint		magic_n;/* magic number */
# define DICT_INDEX_MAGIC_N	76789786
#endif
};

/* Data structure for a foreign key constraint; an example:
FOREIGN KEY (A, B) REFERENCES TABLE2 (C, D) */

struct dict_foreign_struct{
	mem_heap_t*	heap;		/* this object is allocated from
					this memory heap */
	char*		id;		/* id of the constraint as a
					null-terminated string */
	unsigned	n_fields:10;	/* number of indexes' first fields
					for which the the foreign key
					constraint is defined: we allow the
					indexes to contain more fields than
					mentioned in the constraint, as long
					as the first fields are as mentioned */
	unsigned	type:6;		/* 0 or DICT_FOREIGN_ON_DELETE_CASCADE
					or DICT_FOREIGN_ON_DELETE_SET_NULL */
	char*		foreign_table_name;/* foreign table name */
	dict_table_t*	foreign_table;	/* table where the foreign key is */
	const char**	foreign_col_names;/* names of the columns in the
					foreign key */
	char*		referenced_table_name;/* referenced table name */
	dict_table_t*	referenced_table;/* table where the referenced key
					is */
	const char**	referenced_col_names;/* names of the referenced
					columns in the referenced table */
	dict_index_t*	foreign_index;	/* foreign index; we require that
					both tables contain explicitly defined
					indexes for the constraint: InnoDB
					does not generate new indexes
					implicitly */
	dict_index_t*	referenced_index;/* referenced index */
	UT_LIST_NODE_T(dict_foreign_t)
			foreign_list;	/* list node for foreign keys of the
					table */
	UT_LIST_NODE_T(dict_foreign_t)
			referenced_list;/* list node for referenced keys of the
					table */
};

/* The flags for ON_UPDATE and ON_DELETE can be ORed; the default is that
a foreign key constraint is enforced, therefore RESTRICT just means no flag */
#define DICT_FOREIGN_ON_DELETE_CASCADE	1
#define DICT_FOREIGN_ON_DELETE_SET_NULL	2
#define DICT_FOREIGN_ON_UPDATE_CASCADE	4
#define DICT_FOREIGN_ON_UPDATE_SET_NULL	8
#define DICT_FOREIGN_ON_DELETE_NO_ACTION 16
#define DICT_FOREIGN_ON_UPDATE_NO_ACTION 32

/** Tables could be chained together with Foreign key constraint. When
first load the parent table, we would load all of its descedents.
This could result in rescursive calls and out of stack error eventually.
DICT_FK_MAX_RECURSIVE_LOAD defines the maximum number of recursive loads,
when exceeded, the child table will not be loaded. It will be loaded when
the foreign constraint check needs to be run. */
#define DICT_FK_MAX_RECURSIVE_LOAD	250

/** Similarly, when tables are chained together with foreign key constraints
with on cascading delete/update clause, delete from parent table could
result in recursive cascading calls. This defines the maximum number of
such cascading deletes/updates allowed. When exceeded, the delete from
parent table will fail, and user has to drop excessive foreign constraint
before proceeds. */
#define FK_MAX_CASCADE_DEL		300

/* Data structure for a database table */
struct dict_table_struct{
	dulint		id;	/* id of the table */
	mem_heap_t*	heap;	/* memory heap */
	const char*	name;	/* table name */
	const char*	dir_path_of_temp_table;/* NULL or the directory path
				where a TEMPORARY table that was explicitly
				created by a user should be placed if
				innodb_file_per_table is defined in my.cnf;
				in Unix this is usually /tmp/..., in Windows
				\temp\... */
	unsigned	space:32;
				/* space where the clustered index of the
				table is placed */
	unsigned	ibd_file_missing:1;
				/* TRUE if this is in a single-table
				tablespace and the .ibd file is missing; then
				we must return in ha_innodb.cc an error if the
				user tries to query such an orphaned table */
	unsigned	tablespace_discarded:1;
				/* this flag is set TRUE when the user
				calls DISCARD TABLESPACE on this
				table, and reset to FALSE in IMPORT
				TABLESPACE */
	unsigned	cached:1;/* TRUE if the table object has been added
				to the dictionary cache */
	unsigned	flags:8;/* DICT_TF_COMPACT, ... */
	unsigned	n_def:10;/* number of columns defined so far */
	unsigned	n_cols:10;/* number of columns */
	dict_col_t*	cols;	/* array of column descriptions */
	const char*	col_names;
				/* Column names packed in a character string
				"name1\0name2\0...nameN\0".  Until
				the string contains n_cols, it will be
				allocated from a temporary heap.  The final
				string will be allocated from table->heap. */
	hash_node_t	name_hash; /* hash chain node */
	hash_node_t	id_hash; /* hash chain node */
	UT_LIST_BASE_NODE_T(dict_index_t)
			indexes; /* list of indexes of the table */
	UT_LIST_BASE_NODE_T(dict_foreign_t)
			foreign_list;/* list of foreign key constraints
				in the table; these refer to columns
				in other tables */
	UT_LIST_BASE_NODE_T(dict_foreign_t)
			referenced_list;/* list of foreign key constraints
				which refer to this table */
	UT_LIST_NODE_T(dict_table_t)
			table_LRU; /* node of the LRU list of tables */
	ulint		n_mysql_handles_opened;
				/* count of how many handles MySQL has opened
				to this table; dropping of the table is
				NOT allowed until this count gets to zero;
				MySQL does NOT itself check the number of
				open handles at drop */
	unsigned	fk_max_recusive_level:8;
				/*!< maximum recursive level we support when
				loading tables chained together with FK
				constraints. If exceeds this level, we will
				stop loading child table into memory along with
				its parent table */
	ulint		n_foreign_key_checks_running;
				/* count of how many foreign key check
				operations are currently being performed
				on the table: we cannot drop the table while
				there are foreign key checks running on
				it! */
	lock_t*		auto_inc_lock;/* a buffer for an auto-inc lock
				for this table: we allocate the memory here
				so that individual transactions can get it
				and release it without a need to allocate
				space from the lock heap of the trx:
				otherwise the lock heap would grow rapidly
				if we do a large insert from a select */
	dulint		query_cache_inv_trx_id;
				/* transactions whose trx id < than this
				number are not allowed to store to the MySQL
				query cache or retrieve from it; when a trx
				with undo logs commits, it sets this to the
				value of the trx id counter for the tables it
				had an IX lock on */
	UT_LIST_BASE_NODE_T(lock_t)
			locks; /* list of locks on the table */
#ifdef UNIV_DEBUG
	/*----------------------*/
	ibool		does_not_fit_in_memory;
				/* this field is used to specify in simulations
				tables which are so big that disk should be
				accessed: disk access is simulated by
				putting the thread to sleep for a while;
				NOTE that this flag is not stored to the data
				dictionary on disk, and the database will
				forget about value TRUE if it has to reload
				the table definition from disk */
#endif /* UNIV_DEBUG */
	/*----------------------*/
	unsigned	big_rows:1;
				/* flag: TRUE if the maximum length of
				a single row exceeds BIG_ROW_SIZE;
				initialized in dict_table_add_to_cache() */
	unsigned	stat_initialized:1; /* TRUE if statistics have
				been calculated the first time
				after database startup or table creation */
	ib_longlong	stat_n_rows;
				/* approximate number of rows in the table;
				we periodically calculate new estimates */
	ulint		stat_clustered_index_size;
				/* approximate clustered index size in
				database pages */
	ulint		stat_sum_of_other_index_sizes;
				/* other indexes in database pages */
	ulint		stat_modified_counter;
				/* when a row is inserted, updated, or deleted,
				we add 1 to this number; we calculate new
				estimates for the stat_... values for the
				table and the indexes at an interval of 2 GB
				or when about 1 / 16 of table has been
				modified; also when the estimate operation is
				called for MySQL SHOW TABLE STATUS; the
				counter is reset to zero at statistics
				calculation; this counter is not protected by
				any latch, because this is only used for
				heuristics */
	/*----------------------*/
	mutex_t		autoinc_mutex;
				/* mutex protecting the autoincrement
				counter */
	ib_ulonglong	autoinc;/* autoinc counter value to give to the
				next inserted row */
	ulong		n_waiting_or_granted_auto_inc_locks;
				/* This counter is used to track the number
				of granted and pending autoinc locks on this
				table. This value is set after acquiring the
				kernel mutex but we peek the contents to
				determine whether other transactions have
				acquired the AUTOINC lock or not. Of course
				only one transaction can be granted the
				lock but there can be multiple waiters. */
	/*----------------------*/

#ifdef UNIV_DEBUG
	ulint		magic_n;/* magic number */
# define DICT_TABLE_MAGIC_N	76333786
#endif /* UNIV_DEBUG */
};

#ifndef UNIV_NONINL
#include "dict0mem.ic"
#endif

#endif