row0sel.h 12.3 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89
/******************************************************
Select

(c) 1997 Innobase Oy

Created 12/19/1997 Heikki Tuuri
*******************************************************/

#ifndef row0sel_h
#define row0sel_h

#include "univ.i"
#include "data0data.h"
#include "que0types.h"
#include "dict0types.h"
#include "trx0types.h"
#include "row0types.h"
#include "que0types.h"
#include "pars0sym.h"
#include "btr0pcur.h"
#include "read0read.h"
#include "row0mysql.h"

/*************************************************************************
Creates a select node struct. */

sel_node_t*
sel_node_create(
/*============*/
				/* out, own: select node struct */
	mem_heap_t*	heap);	/* in: memory heap where created */
/*************************************************************************
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. */

void
sel_node_free_private(
/*==================*/
	sel_node_t*	node);	/* in: select node struct */
/*************************************************************************
Frees a prefetch buffer for a column, including the dynamically allocated
memory for data stored there. */

void
sel_col_prefetch_buf_free(
/*======================*/
	sel_buf_t*	prefetch_buf);	/* in, own: prefetch buffer */
/*************************************************************************
Gets the plan node for the nth table in a join. */
UNIV_INLINE
plan_t*
sel_node_get_nth_plan(
/*==================*/
	sel_node_t*	node,
	ulint		i);
/**************************************************************************
Performs a select step. This is a high-level function used in SQL execution
graphs. */

que_thr_t*
row_sel_step(
/*=========*/
				/* out: query thread to run next or NULL */
	que_thr_t*	thr);	/* in: query thread */
/**************************************************************************
Performs an execution step of an open or close cursor statement node. */
UNIV_INLINE
que_thr_t*
open_step(
/*======*/
				/* out: query thread to run next or NULL */
	que_thr_t*	thr);	/* in: query thread */
/**************************************************************************
Performs a fetch for a cursor. */

que_thr_t*
fetch_step(
/*=======*/
				/* out: query thread to run next or NULL */
	que_thr_t*	thr);	/* in: query thread */
/***************************************************************
Prints a row in a select result. */

que_thr_t*
row_printf_step(
/*============*/
				/* out: query thread to run next or NULL */
	que_thr_t*	thr);	/* in: query thread */
/********************************************************************
unknown's avatar
unknown committed
90 91 92 93 94
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. */
95 96 97 98 99 100 101 102 103 104

void
row_sel_convert_mysql_key_to_innobase(
/*==================================*/
	dtuple_t*	tuple,		/* in: tuple where to build;
					NOTE: we assume that the type info
					in the tuple is already according
					to index! */
	byte*		buf,		/* in: buffer to use in field
					conversions */
unknown's avatar
unknown committed
105
	ulint		buf_len,	/* in: buffer length */
106 107
	dict_index_t*	index,		/* in: index of the key value */
	byte*		key_ptr,	/* in: MySQL key value */
108 109
	ulint		key_len,	/* in: MySQL key value length */
	trx_t*		trx);		/* in: transaction */
110 111 112 113 114 115 116 117 118 119 120 121
/************************************************************************
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! */

ulint
row_search_for_mysql(
/*=================*/
					/* out: DB_SUCCESS,
					DB_RECORD_NOT_FOUND, 
122 123
					DB_END_OF_INDEX, DB_DEADLOCK,
					or DB_TOO_BIG_RECORD */
124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140
	byte*		buf,		/* in/out: buffer for the fetched
					row in the MySQL format */
	ulint		mode,		/* in: search mode PAGE_CUR_L, ... */
	row_prebuilt_t*	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' */
	ulint		match_mode,	/* in: 0 or ROW_SEL_EXACT or
					ROW_SEL_EXACT_PREFIX */ 
	ulint		direction);	/* in: 0 or ROW_SEL_NEXT or
					ROW_SEL_PREV; NOTE: if this is != 0,
					then prebuilt must have a pcur
					with stored position! In opening of a
					cursor 'direction' should be 0. */
141 142 143 144 145 146 147
/***********************************************************************
Checks if MySQL at the moment is allowed for this table to retrieve a
consistent read result, or store it to the query cache. */

ibool
row_search_check_if_query_cache_permitted(
/*======================================*/
148 149 150 151 152
					/* out: TRUE if storing or retrieving
					from the query cache is permitted */
	trx_t*		trx,		/* in: transaction object */
	const char*	norm_name);	/* in: concatenation of database name,
					'/' char, table name */
153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347


/* A structure for caching column values for prefetched rows */
struct sel_buf_struct{
	byte*		data;	/* data, or NULL; if not NULL, this field
				has allocated memory which must be explicitly
				freed; can be != NULL even when len is
				UNIV_SQL_NULL */
	ulint		len;	/* data length or UNIV_SQL_NULL */
	ulint		val_buf_size;
				/* size of memory buffer allocated for data:
				this can be more than len; this is defined
				when data != NULL */
};

struct plan_struct{
	dict_table_t*	table;		/* table struct in the dictionary
					cache */
	dict_index_t*	index;		/* table index used in the search */
	btr_pcur_t	pcur;		/* persistent cursor used to search
					the index */
	ibool		asc;		/* TRUE if cursor traveling upwards */
	ibool		pcur_is_open;	/* TRUE if pcur has been positioned
					and we can try to fetch new rows */
	ibool		cursor_at_end;	/* TRUE if the cursor is open but
					we know that there are no more
					qualifying rows left to retrieve from
					the index tree; NOTE though, that
					there may still be unprocessed rows in
					the prefetch stack; always FALSE when
					pcur_is_open is FALSE */
	ibool		stored_cursor_rec_processed;
					/* TRUE if the pcur position has been
					stored and the record it is positioned
					on has already been processed */
	que_node_t**	tuple_exps;	/* array of expressions which are used
					to calculate the field values in the
					search tuple: there is one expression
					for each field in the search tuple */
	dtuple_t*	tuple;		/* search tuple */
	ulint		mode;		/* search mode: PAGE_CUR_G, ... */
	ulint		n_exact_match;	/* number of first fields in the search
					tuple which must be exactly matched */
	ibool		unique_search;	/* TRUE if we are searching an
					index record with a unique key */
	ulint		n_rows_fetched;	/* number of rows fetched using pcur
					after it was opened */
	ulint		n_rows_prefetched;/* number of prefetched rows cached
					for fetch: fetching several rows in
					the same mtr saves CPU time */
	ulint		first_prefetched;/* index of the first cached row in
					select buffer arrays for each column */
	ibool		no_prefetch;	/* no prefetch for this table */
	ibool		mixed_index;	/* TRUE if index is a clustered index
					in a mixed cluster */
	sym_node_list_t	columns;	/* symbol table nodes for the columns
					to retrieve from the table */
	UT_LIST_BASE_NODE_T(func_node_t)
			end_conds;	/* conditions which determine the
					fetch limit of the index segment we
					have to look at: when one of these
					fails, the result set has been
					exhausted for the cursor in this
					index; these conditions are normalized
					so that in a comparison the column
					for this table is the first argument */
	UT_LIST_BASE_NODE_T(func_node_t)
			other_conds;	/* the rest of search conditions we can
					test at this table in a join */
	ibool		must_get_clust;	/* TRUE if index is a non-clustered
					index and we must also fetch the
					clustered index record; this is the
					case if the non-clustered record does
					not contain all the needed columns, or
					if this is a single-table explicit
					cursor, or a searched update or
					delete */
	ulint*		clust_map;	/* map telling how clust_ref is built
					from the fields of a non-clustered
					record */
	dtuple_t*	clust_ref;	/* the reference to the clustered
					index entry is built here if index is
					a non-clustered index */
	btr_pcur_t	clust_pcur;	/* if index is non-clustered, we use
					this pcur to search the clustered
					index */
	mem_heap_t*	old_vers_heap;	/* memory heap used in building an old
					version of a row, or NULL */	
};	

struct sel_node_struct{
	que_common_t	common;		/* node type: QUE_NODE_SELECT */
	ulint		state;		/* node state */
	que_node_t*	select_list;	/* select list */
	sym_node_t*	into_list;	/* variables list or NULL */
	sym_node_t*	table_list;	/* table list */
	ibool		asc;		/* TRUE if the rows should be fetched
					in an ascending order */
	ibool		set_x_locks;	/* TRUE if the cursor is for update or
					delete, which means that a row x-lock
					should be placed on the cursor row */
	ibool		select_will_do_update;
					/* TRUE if the select is for a searched
					update which can be performed in-place:
					in this case the select will take care
					of the update */
	ulint		latch_mode;	/* BTR_SEARCH_LEAF, or BTR_MODIFY_LEAF
					if select_will_do_update is TRUE */
	ulint		row_lock_mode;	/* LOCK_X or LOCK_S */
	ulint		n_tables;	/* number of tables */
	ulint		fetch_table;	/* number of the next table to access
					in the join */
	plan_t*		plans;		/* array of n_tables many plan nodes
					containing the search plan and the
					search data structures */
	que_node_t*	search_cond;	/* search condition */
	read_view_t*	read_view;	/* if the query is a non-locking
					consistent read, its read view is
					placed here, otherwise NULL */
	ibool		consistent_read;/* TRUE if the select is a consistent,
					non-locking read */
	order_node_t*	order_by;	/* order by column definition, or
					NULL */
	ibool		is_aggregate;	/* TRUE if the select list consists of
					aggregate functions */
	ibool		aggregate_already_fetched;
					/* TRUE if the aggregate row has
					already been fetched for the current
					cursor */
	ibool		can_get_updated;/* this is TRUE if the select is in a
					single-table explicit cursor which can
					get updated within the stored procedure,
					or in a searched update or delete;
					NOTE that to determine of an explicit
					cursor if it can get updated, the
					parser checks from a stored procedure
					if it contains positioned update or
					delete statements */
	sym_node_t*	explicit_cursor;/* not NULL if an explicit cursor */
	UT_LIST_BASE_NODE_T(sym_node_t)
			copy_variables; /* variables whose values we have to
					copy when an explicit cursor is opened,
					so that they do not change between
					fetches */
};
	
/* Select node states */
#define	SEL_NODE_CLOSED		0	/* it is a declared cursor which is not
					currently open */
#define SEL_NODE_OPEN		1	/* intention locks not yet set on
					tables */
#define SEL_NODE_FETCH		2	/* intention locks have been set */
#define SEL_NODE_NO_MORE_ROWS	3	/* cursor has reached the result set
					end */

/* Fetch statement node */
struct fetch_node_struct{
	que_common_t	common;		/* type: QUE_NODE_FETCH */
	sel_node_t*	cursor_def;	/* cursor definition */
	sym_node_t*	into_list;	/* variables to set */
};

/* Open or close cursor statement node */
struct open_node_struct{
	que_common_t	common;		/* type: QUE_NODE_OPEN */
	ulint		op_type;	/* ROW_SEL_OPEN_CURSOR or
					ROW_SEL_CLOSE_CURSOR */
	sel_node_t*	cursor_def;	/* cursor definition */
};

/* Row printf statement node */
struct row_printf_node_struct{
	que_common_t	common;		/* type: QUE_NODE_ROW_PRINTF */
	sel_node_t*	sel_node;	/* select */
};

#define ROW_SEL_OPEN_CURSOR	0
#define ROW_SEL_CLOSE_CURSOR	1

/* Flags for the MySQL interface */
#define ROW_SEL_NEXT		1
#define ROW_SEL_PREV		2

#define ROW_SEL_EXACT		1	/* search using a complete key value */
#define ROW_SEL_EXACT_PREFIX 	2	/* search using a key prefix which
					must match to rows: the prefix may
					contain an incomplete field (the
					last field in prefix may be just
					a prefix of a fixed length column) */

#ifndef UNIV_NONINL
#include "row0sel.ic"
#endif

#endif