Select. More...

#include "univ.i"
#include "btr0pcur.h"
#include "data0data.h"
#include "dict0stats.h"
#include "dict0types.h"
#include "pars0sym.h"
#include "que0types.h"
#include "read0types.h"
#include "row0mysql.h"
#include "row0types.h"
#include "trx0types.h"
#include "row0sel.ic"

Classes
struct	sel_buf_t
	A structure for caching column values for prefetched rows. More...

struct	plan_t
	Query plan. More...

struct	sel_node_t
	Select statement node. More...

struct	fetch_node_t
	Fetch statement node. More...

struct	open_node_t
	Open or close cursor statement node. More...

Enumerations
enum	sel_node_state { SEL_NODE_CLOSED , SEL_NODE_OPEN , SEL_NODE_FETCH , SEL_NODE_NO_MORE_ROWS }
	Select node states. More...

enum	open_node_op { ROW_SEL_OPEN_CURSOR , ROW_SEL_CLOSE_CURSOR }
	Open or close cursor operation type. More...

enum	row_sel_direction { ROW_SEL_NEXT = 1 , ROW_SEL_PREV = 2 }
	Search direction for the MySQL interface. More...

enum	row_sel_match_mode { ROW_SEL_EXACT = 1 , ROW_SEL_EXACT_PREFIX }
	Match mode for the MySQL interface. More...

Functions
sel_node_t *	sel_node_create (mem_heap_t *heap)
	Creates a select node struct. More...

void	sel_node_free_private (sel_node_t *node)
	Frees the memory private to a select node when a query graph is freed, does not free the heap where the node was originally created. More...

void	sel_col_prefetch_buf_free (sel_buf_t *prefetch_buf)
	Frees a prefetch buffer for a column, including the dynamically allocated memory for data stored there. More...

static plan_t *	sel_node_get_nth_plan (sel_node_t *node, ulint i)
	Gets the plan node for the nth table in a join. More...

que_thr_t *	row_sel_step (que_thr_t *thr)
	Performs a select step. More...

static que_thr_t *	open_step (que_thr_t *thr)
	Performs an execution step of an open or close cursor statement node. More...

que_thr_t *	fetch_step (que_thr_t *thr)
	Performs a fetch for a cursor. More...

void	row_sel_copy_cached_fields_for_mysql (byte buf, const byte cached_rec, row_prebuilt_t *prebuilt)
	Copy used fields from cached row. More...

bool	row_sel_store_mysql_rec (byte mysql_rec, row_prebuilt_t prebuilt, const rec_t rec, const dtuple_t vrow, bool rec_clust, const dict_index_t rec_index, const dict_index_t prebuilt_index, const ulint offsets, bool clust_templ_for_sec, lob::undo_vers_t lob_undo, mem_heap_t *&blob_heap)
	Convert a row in the Innobase format to a row in the MySQL format. More...

void	row_sel_convert_mysql_key_to_innobase (dtuple_t tuple, byte buf, ulint buf_len, dict_index_t index, const byte key_ptr, ulint key_len)
	Converts a key value stored in MySQL format to an Innobase dtuple. More...

static dberr_t	row_search_for_mysql (byte buf, page_cur_mode_t mode, row_prebuilt_t prebuilt, ulint match_mode, ulint direction)
	Searches for rows in the database. More...

dberr_t	row_search_no_mvcc (byte buf, page_cur_mode_t mode, row_prebuilt_t prebuilt, ulint match_mode, ulint direction)
	Searches for rows in the database using cursor. More...

dberr_t	row_search_mvcc (byte buf, page_cur_mode_t mode, row_prebuilt_t prebuilt, ulint match_mode, const ulint direction)
	Searches for rows in the database using cursor. More...

dberr_t	row_count_rtree_recs (row_prebuilt_t prebuilt, ulint n_rows, ulint *n_dups)
	Count rows in a R-Tree leaf level. More...

dberr_t	row_search_max_autoinc (dict_index_t index, const char col_name, uint64_t *value)
	Read the max AUTOINC value from an index. More...

void	row_sel_field_store_in_mysql_format_func (byte dest, const mysql_row_templ_t templ, const dict_index_t index, ulint field_no, const byte data, ulint len, ulint sec_field)
	Stores a non-SQL-NULL field in the MySQL format. More...

static void	row_sel_field_store_in_mysql_format (byte dest, const mysql_row_templ_t templ, const dict_index_t idx, ulint field, const byte src, ulint len, ulint sec)
	Convert a non-SQL-NULL field from Innobase format to MySQL format. More...

bool	row_search_table_stats (const char db_name, const char tbl_name, TableStatsRecord &table_stats)
	Search the record present in innodb_table_stats table using db_name, table_name and fill it in table stats structure. More...

bool	row_search_index_stats (const char db_name, const char tbl_name, const char index_name, ulint col_offset, ulonglong cardinality)
	Search the record present in innodb_index_stats using db_name, table name and index_name and fill the cardinality for the each column. More...

Detailed Description

Select.

Created 12/19/1997 Heikki Tuuri

Enumeration Type Documentation

◆ open_node_op

enum open_node_op

Open or close cursor operation type.

Enumerator
ROW_SEL_OPEN_CURSOR	open cursor
ROW_SEL_CLOSE_CURSOR	close cursor

◆ row_sel_direction

enum row_sel_direction

Search direction for the MySQL interface.

Enumerator
ROW_SEL_NEXT	ascending direction
ROW_SEL_PREV	descending direction

◆ row_sel_match_mode

enum row_sel_match_mode

Match mode for the MySQL interface.

Enumerator
ROW_SEL_EXACT	search using a complete key value
ROW_SEL_EXACT_PREFIX	search using a key prefix which must match rows: the prefix may contain an incomplete field (the last field in prefix may be just a prefix of a fixed length column)

◆ sel_node_state

enum sel_node_state

Select node states.

Enumerator
SEL_NODE_CLOSED	it is a declared cursor which is not currently open
SEL_NODE_OPEN	intention locks not yet set on tables
SEL_NODE_FETCH	intention locks have been set
SEL_NODE_NO_MORE_ROWS	cursor has reached the result set end

Function Documentation

◆ fetch_step()

que_thr_t * fetch_step ( que_thr_t * thr )

Performs a fetch for a cursor.

Returns: query thread to run next or NULL in: query thread; query thread to run next or NULL

Parameters

thr	in: query thread

◆ open_step()

static que_thr_t * open_step ( que_thr_t * thr )

inlinestatic

Performs an execution step of an open or close cursor statement node.

Returns: query thread to run next or NULL in: query thread

◆ row_count_rtree_recs()

dberr_t row_count_rtree_recs	(	row_prebuilt_t *	prebuilt,
		ulint *	n_rows,
		ulint *	n_dups
	)

Count rows in a R-Tree leaf level.

Returns: DB_SUCCESS if successful out: number of dup entries seen in the consistent read; DB_SUCCESS if successful

Parameters

prebuilt	in: prebuilt struct for the table handle; this contains the info of search_tuple, index; if search tuple contains 0 fields then we position the cursor at the start or the end of the index, depending on 'mode'
n_rows	out: number of entries seen in the consistent read
n_dups	out: number of dup entries

◆ row_search_for_mysql()

static dberr_t row_search_for_mysql	(	byte *	buf,
		page_cur_mode_t	mode,
		row_prebuilt_t *	prebuilt,
		ulint	match_mode,
		ulint	direction
	)

inlinestatic

Searches for rows in the database.

This is used in the interface to MySQL. This function opens a cursor, and also implements fetch next and fetch prev. NOTE that if we do a search with a full key value from a unique index (ROW_SEL_EXACT), then we will not store the cursor position and fetch next or fetch prev must not be tried to the cursor!

Parameters

[out]	buf	buffer for the fetched row in MySQL format
[in]	mode	search mode PAGE_CUR_L
[in,out]	prebuilt	prebuilt struct for the table handler; this contains the info to search_tuple, index; if search tuple contains 0 field then we position the cursor at start or the end of index, depending on 'mode'
[in]	match_mode	0 or ROW_SEL_EXACT or ROW_SEL_EXACT_PREFIX
[in]	direction	0 or ROW_SEL_NEXT or ROW_SEL_PREV; Note: if this is != 0, then prebuilt must has a pcur with stored position! In opening of a cursor 'direction' should be 0.

Returns: DB_SUCCESS, DB_RECORD_NOT_FOUND, DB_END_OF_INDEX, DB_DEADLOCK, DB_LOCK_TABLE_FULL, DB_CORRUPTION, or DB_TOO_BIG_RECORD

◆ row_search_index_stats()

bool row_search_index_stats	(	const char *	db_name,
		const char *	tbl_name,
		const char *	index_name,
		ulint	col_offset,
		ulonglong *	cardinality
	)

Search the record present in innodb_index_stats using db_name, table name and index_name and fill the cardinality for the each column.

Parameters

[in]	db_name	database name
[in]	tbl_name	table name
[in]	index_name	index name
[in]	col_offset	offset of the column in the index
[out]	cardinality	cardinality of the column.

Returns: true if successful else false.

Number of fields to search in the table.

Column number of innodb_index_stats.database_name.

Column number of innodb_index_stats.table_name.

Column number of innodb_index_stats.index_name.

Column number of innodb_index_stats.stat_value.

Search the innodb_index_stats table using (database_name, table_name, index_name).

◆ row_search_max_autoinc()

dberr_t row_search_max_autoinc	(	dict_index_t *	index,
		const char *	col_name,
		uint64_t *	value
	)

Read the max AUTOINC value from an index.

Returns: DB_SUCCESS if all OK else error code out: AUTOINC value read; DB_SUCCESS if all OK else error code, DB_RECORD_NOT_FOUND if column name can't be found in index

Parameters

index	in: index to search
col_name	in: name of autoinc column
value	out: AUTOINC value read

◆ row_search_mvcc()

dberr_t row_search_mvcc	(	byte *	buf,
		page_cur_mode_t	mode,
		row_prebuilt_t *	prebuilt,
		ulint	match_mode,
		const ulint	direction
	)

Searches for rows in the database using cursor.

Function is mainly used for tables that are shared accorss connection and so it employs technique that can help re-construct the rows that transaction is suppose to see. It also has optimization such as pre-caching the rows, using AHI, etc.

Parameters

[out]	buf	buffer for the fetched row in MySQL format
[in]	mode	search mode PAGE_CUR_L
[in,out]	prebuilt	prebuilt struct for the table handler; this contains the info to search_tuple, index; if search tuple contains 0 field then we position the cursor at start or the end of index, depending on 'mode'
[in]	match_mode	0 or ROW_SEL_EXACT or ROW_SEL_EXACT_PREFIX
[in]	direction	0 or ROW_SEL_NEXT or ROW_SEL_PREV; Note: if this is != 0, then prebuilt must has a pcur with stored position! In opening of a cursor 'direction' should be 0.

Returns: DB_SUCCESS or error code

Compare the last record of the page with end range passed to InnoDB when there is no ICP and number of loops in row_search_mvcc for rows found but not reporting due to search views etc. When scanning a multi-value index, we don't perform the check because we cannot convert the indexed value (single scalar element) into the primary index (virtual) column type (array of values).

Secondary index record but the template based on PK.

Create offsets based on prebuilt index.

In case of prebuilt->fetch, set the error in prebuilt->end_range.

◆ row_search_no_mvcc()

dberr_t row_search_no_mvcc	(	byte *	buf,
		page_cur_mode_t	mode,
		row_prebuilt_t *	prebuilt,
		ulint	match_mode,
		ulint	direction
	)

Searches for rows in the database using cursor.

Function is for temporary tables that are not shared across connections and so lot of complexity is reduced especially locking and transaction related. The cursor is an iterator over the table/index.

Parameters

[out]	buf	buffer for the fetched row in MySQL format
[in]	mode	search mode PAGE_CUR_L
[in,out]	prebuilt	prebuilt struct for the table handler; this contains the info to search_tuple, index; if search tuple contains 0 field then we position the cursor at start or the end of index, depending on 'mode'
[in]	match_mode	0 or ROW_SEL_EXACT or ROW_SEL_EXACT_PREFIX
[in]	direction	0 or ROW_SEL_NEXT or ROW_SEL_PREV; Note: if this is != 0, then prebuilt must has a pcur with stored position! In opening of a cursor 'direction' should be 0.

Returns: DB_SUCCESS or error code

◆ row_search_table_stats()

bool row_search_table_stats	(	const char *	db_name,
		const char *	tbl_name,
		TableStatsRecord &	table_stats
	)

Search the record present in innodb_table_stats table using db_name, table_name and fill it in table stats structure.

Parameters

[in]	db_name	database name
[in]	tbl_name	table name
[out]	table_stats	stats table structure.

Returns: true if successful else false.

◆ row_sel_convert_mysql_key_to_innobase()

void row_sel_convert_mysql_key_to_innobase	(	dtuple_t *	tuple,
		byte *	buf,
		ulint	buf_len,
		dict_index_t *	index,
		const byte *	key_ptr,
		ulint	key_len
	)

Converts a key value stored in MySQL format to an Innobase dtuple.

The last field of the key value may be just a prefix of a fixed length field: hence the parameter key_len. But currently we do not allow search keys where the last field is only a prefix of the full key field len and print a warning if such appears.

Parameters

[in,out]	tuple	Tuple where to build; NOTE: we assume that the type info in the tuple is already according to index!
[in]	buf	Buffer to use in field conversions; NOTE that dtuple->data may end up pointing inside buf so do not discard that buffer while the tuple is being used. See row_mysql_store_col_in_innobase_format() in the case of DATA_INT.
[in]	buf_len	Buffer length.
[in]	index	Index of the key value.
[in]	key_ptr	MySQL key value
[in]	key_len	MySQL key value length

◆ row_sel_copy_cached_fields_for_mysql()

void row_sel_copy_cached_fields_for_mysql	(	byte *	buf,
		const byte *	cached_rec,
		row_prebuilt_t *	prebuilt
	)

Copy used fields from cached row.

Copy cache record field by field, don't touch fields that are not covered by current key.

Parameters

[out]	buf	Where to copy the MySQL row.
[in]	cached_rec	What to copy (in MySQL row format).
[in]	prebuilt	prebuilt struct.

◆ row_sel_field_store_in_mysql_format()

static void row_sel_field_store_in_mysql_format	(	byte *	dest,
		const mysql_row_templ_t *	templ,
		const dict_index_t *	idx,
		ulint	field,
		const byte *	src,
		ulint	len,
		ulint	sec
	)

inlinestatic

Convert a non-SQL-NULL field from Innobase format to MySQL format.

◆ row_sel_field_store_in_mysql_format_func()

void row_sel_field_store_in_mysql_format_func	(	byte *	dest,
		const mysql_row_templ_t *	templ,
		const dict_index_t *	index,
		ulint	field_no,
		const byte *	data,
		ulint	len,
		ulint	sec_field
	)

Stores a non-SQL-NULL field in the MySQL format.

The counterpart of this function is row_mysql_store_col_in_innobase_format() in row0mysql.cc.

Parameters

[in,out]	dest	buffer where to store; NOTE that BLOBs are not in themselves stored here: the caller must allocate and copy the BLOB into buffer before, and pass the pointer to the BLOB in 'data'
[in]	templ	MySQL column template. Its following fields are referenced: type, is_unsigned, mysql_col_len, mbminlen, mbmaxlen
[in]	index	InnoDB index
[in]	field_no	templ->rec_field_no or templ->clust_rec_field_no or templ->icp_rec_field_no
[in]	data	data to store
[in]	len	length of the data
[in]	sec_field	secondary index field no if the secondary index record but the prebuilt template is in clustered index format and used only for end range comparison.

◆ row_sel_step()

que_thr_t * row_sel_step ( que_thr_t * thr )

Performs a select step.

This is a high-level function used in SQL execution graphs.

Returns: query thread to run next or NULL in: query thread

This is a high-level function used in SQL execution graphs.

Returns: query thread to run next or NULL

Parameters

thr	in: query thread

◆ row_sel_store_mysql_rec()

bool row_sel_store_mysql_rec	(	byte *	mysql_rec,
		row_prebuilt_t *	prebuilt,
		const rec_t *	rec,
		const dtuple_t *	vrow,
		bool	rec_clust,
		const dict_index_t *	rec_index,
		const dict_index_t *	prebuilt_index,
		const ulint *	offsets,
		bool	clust_templ_for_sec,
		lob::undo_vers_t *	lob_undo,
		mem_heap_t *&	blob_heap
	)

Convert a row in the Innobase format to a row in the MySQL format.

Note that the template in prebuilt may advise us to copy only a few columns to mysql_rec, other columns are left blank. All columns may not be needed in the query.

Parameters

[out]	mysql_rec	row in the MySQL format
[in,out]	prebuilt	prebuilt structure
[in]	rec	Innobase record in the index which was described in prebuilt's template, or in the clustered index; must be protected by a page latch
[in]	vrow	virtual columns
[in]	rec_clust	true if rec is in the clustered index instead of index which could belong to prebuilt->index
[in]	rec_index	index of rec
[in]	prebuilt_index	prebuilt->index
[in]	offsets	array returned by rec_get_offsets(rec)
[in]	clust_templ_for_sec	true if rec belongs to secondary index but the prebuilt->template is in clustered index format and it is used only for end range comparison
[in]	lob_undo	the LOB undo information.
[in,out]	blob_heap	If not null then use this heap for BLOBs

Returns: true on success, false if not all columns could be retrieved

◆ sel_col_prefetch_buf_free()

void sel_col_prefetch_buf_free ( sel_buf_t * prefetch_buf )

Frees a prefetch buffer for a column, including the dynamically allocated memory for data stored there.

in, own: prefetch buffer

Parameters

prefetch_buf in, own: prefetch buffer

◆ sel_node_create()

sel_node_t * sel_node_create ( mem_heap_t * heap )

Creates a select node struct.

Returns: own: select node struct in: memory heap where created; own: select node struct

Parameters

heap	in: memory heap where created

◆ sel_node_free_private()

void sel_node_free_private ( sel_node_t * node )

Frees the memory private to a select node when a query graph is freed, does not free the heap where the node was originally created.

in: select node struct

Parameters

node	in: select node struct

◆ sel_node_get_nth_plan()

static plan_t * sel_node_get_nth_plan	(	sel_node_t *	node,
		ulint	i
	)

inlinestatic

Gets the plan node for the nth table in a join.

Parameters

[in]	node	select node
[in]	i	get ith plan node

Returns: plan node

Classes

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

◆ open_node_op

◆ row_sel_direction

◆ row_sel_match_mode

◆ sel_node_state

Function Documentation

◆ fetch_step()

◆ open_step()

◆ row_count_rtree_recs()

◆ row_search_for_mysql()

◆ row_search_index_stats()

◆ row_search_max_autoinc()

◆ row_search_mvcc()

◆ row_search_no_mvcc()

◆ row_search_table_stats()

◆ row_sel_convert_mysql_key_to_innobase()

◆ row_sel_copy_cached_fields_for_mysql()

◆ row_sel_field_store_in_mysql_format()

◆ row_sel_field_store_in_mysql_format_func()

◆ row_sel_step()

◆ row_sel_store_mysql_rec()

◆ sel_col_prefetch_buf_free()

◆ sel_node_create()

◆ sel_node_free_private()

◆ sel_node_get_nth_plan()