ha0ha.c 11.3 KB
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 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455
/*****************************************************************************

Copyright (c) 1994, 2009, Innobase Oy. All Rights Reserved.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place, Suite 330, Boston, MA 02111-1307 USA

*****************************************************************************/

/********************************************************************//**
@file ha/ha0ha.c
The hash table with external chains

Created 8/22/1994 Heikki Tuuri
*************************************************************************/

#include "ha0ha.h"
#ifdef UNIV_NONINL
#include "ha0ha.ic"
#endif

#ifdef UNIV_DEBUG
# include "buf0buf.h"
#endif /* UNIV_DEBUG */
#ifdef UNIV_SYNC_DEBUG
# include "btr0sea.h"
#endif /* UNIV_SYNC_DEBUG */
#include "page0page.h"

/*************************************************************//**
Creates a hash table with at least n array cells.  The actual number
of cells is chosen to be a prime number slightly bigger than n.
@return	own: created table */
UNIV_INTERN
hash_table_t*
ha_create_func(
/*===========*/
	ulint	n,		/*!< in: number of array cells */
#ifdef UNIV_SYNC_DEBUG
	ulint	mutex_level,	/*!< in: level of the mutexes in the latching
				order: this is used in the debug version */
#endif /* UNIV_SYNC_DEBUG */
	ulint	n_mutexes)	/*!< in: number of mutexes to protect the
				hash table: must be a power of 2, or 0 */
{
	hash_table_t*	table;
#ifndef UNIV_HOTBACKUP
	ulint		i;
#endif /* !UNIV_HOTBACKUP */

	ut_ad(ut_is_2pow(n_mutexes));
	table = hash_create(n);

#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
# ifndef UNIV_HOTBACKUP
	table->adaptive = TRUE;
# endif /* !UNIV_HOTBACKUP */
#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
	/* Creating MEM_HEAP_BTR_SEARCH type heaps can potentially fail,
	but in practise it never should in this case, hence the asserts. */

	if (n_mutexes == 0) {
		table->heap = mem_heap_create_in_btr_search(
			ut_min(4096, MEM_MAX_ALLOC_IN_BUF));
		ut_a(table->heap);

		return(table);
	}

#ifndef UNIV_HOTBACKUP
	hash_create_mutexes(table, n_mutexes, mutex_level);

	table->heaps = mem_alloc(n_mutexes * sizeof(void*));

	for (i = 0; i < n_mutexes; i++) {
		table->heaps[i] = mem_heap_create_in_btr_search(4096);
		ut_a(table->heaps[i]);
	}
#endif /* !UNIV_HOTBACKUP */

	return(table);
}

/*************************************************************//**
Empties a hash table and frees the memory heaps. */
UNIV_INTERN
void
ha_clear(
/*=====*/
	hash_table_t*	table)	/*!< in, own: hash table */
{
	ulint	i;
	ulint	n;

	ut_ad(table);
	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
#ifdef UNIV_SYNC_DEBUG
	ut_ad(rw_lock_own(&btr_search_latch, RW_LOCK_EXCLUSIVE));
#endif /* UNIV_SYNC_DEBUG */

#ifndef UNIV_HOTBACKUP
	/* Free the memory heaps. */
	n = table->n_mutexes;

	for (i = 0; i < n; i++) {
		mem_heap_free(table->heaps[i]);
	}
#endif /* !UNIV_HOTBACKUP */

	/* Clear the hash table. */
	n = hash_get_n_cells(table);

	for (i = 0; i < n; i++) {
		hash_get_nth_cell(table, i)->node = NULL;
	}
}

/*************************************************************//**
Inserts an entry into a hash table. If an entry with the same fold number
is found, its node is updated to point to the new data, and no new node
is inserted.
@return	TRUE if succeed, FALSE if no more memory could be allocated */
UNIV_INTERN
ibool
ha_insert_for_fold_func(
/*====================*/
	hash_table_t*	table,	/*!< in: hash table */
	ulint		fold,	/*!< in: folded value of data; if a node with
				the same fold value already exists, it is
				updated to point to the same data, and no new
				node is created! */
#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
	buf_block_t*	block,	/*!< in: buffer block containing the data */
#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
	void*		data)	/*!< in: data, must not be NULL */
{
	hash_cell_t*	cell;
	ha_node_t*	node;
	ha_node_t*	prev_node;
	ulint		hash;

	ut_ad(data);
	ut_ad(table);
	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
	ut_a(block->frame == page_align(data));
#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
	ASSERT_HASH_MUTEX_OWN(table, fold);

	hash = hash_calc_hash(fold, table);

	cell = hash_get_nth_cell(table, hash);

	prev_node = cell->node;

	while (prev_node != NULL) {
		if (prev_node->fold == fold) {
#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
# ifndef UNIV_HOTBACKUP
			if (table->adaptive) {
				buf_block_t* prev_block = prev_node->block;
				ut_a(prev_block->frame
				     == page_align(prev_node->data));
				ut_a(prev_block->n_pointers > 0);
				prev_block->n_pointers--;
				block->n_pointers++;
			}
# endif /* !UNIV_HOTBACKUP */

			prev_node->block = block;
#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
			prev_node->data = data;

			return(TRUE);
		}

		prev_node = prev_node->next;
	}

	/* We have to allocate a new chain node */

	node = mem_heap_alloc(hash_get_heap(table, fold), sizeof(ha_node_t));

	if (node == NULL) {
		/* It was a btr search type memory heap and at the moment
		no more memory could be allocated: return */

		ut_ad(hash_get_heap(table, fold)->type & MEM_HEAP_BTR_SEARCH);

		return(FALSE);
	}

	ha_node_set_data(node, block, data);

#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
# ifndef UNIV_HOTBACKUP
	if (table->adaptive) {
		block->n_pointers++;
	}
# endif /* !UNIV_HOTBACKUP */
#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */

	node->fold = fold;

	node->next = NULL;

	prev_node = cell->node;

	if (prev_node == NULL) {

		cell->node = node;

		return(TRUE);
	}

	while (prev_node->next != NULL) {

		prev_node = prev_node->next;
	}

	prev_node->next = node;

	return(TRUE);
}

/***********************************************************//**
Deletes a hash node. */
UNIV_INTERN
void
ha_delete_hash_node(
/*================*/
	hash_table_t*	table,		/*!< in: hash table */
	ha_node_t*	del_node)	/*!< in: node to be deleted */
{
	ut_ad(table);
	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
# ifndef UNIV_HOTBACKUP
	if (table->adaptive) {
		ut_a(del_node->block->frame = page_align(del_node->data));
		ut_a(del_node->block->n_pointers > 0);
		del_node->block->n_pointers--;
	}
# endif /* !UNIV_HOTBACKUP */
#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */

	HASH_DELETE_AND_COMPACT(ha_node_t, next, table, del_node);
}

/*********************************************************//**
Looks for an element when we know the pointer to the data, and updates
the pointer to data, if found. */
UNIV_INTERN
void
ha_search_and_update_if_found_func(
/*===============================*/
	hash_table_t*	table,	/*!< in/out: hash table */
	ulint		fold,	/*!< in: folded value of the searched data */
	void*		data,	/*!< in: pointer to the data */
#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
	buf_block_t*	new_block,/*!< in: block containing new_data */
#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
	void*		new_data)/*!< in: new pointer to the data */
{
	ha_node_t*	node;

	ut_ad(table);
	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
	ASSERT_HASH_MUTEX_OWN(table, fold);
#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
	ut_a(new_block->frame == page_align(new_data));
#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */

	node = ha_search_with_data(table, fold, data);

	if (node) {
#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
# ifndef UNIV_HOTBACKUP
		if (table->adaptive) {
			ut_a(node->block->n_pointers > 0);
			node->block->n_pointers--;
			new_block->n_pointers++;
		}
# endif /* !UNIV_HOTBACKUP */

		node->block = new_block;
#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
		node->data = new_data;
	}
}

#ifndef UNIV_HOTBACKUP
/*****************************************************************//**
Removes from the chain determined by fold all nodes whose data pointer
points to the page given. */
UNIV_INTERN
void
ha_remove_all_nodes_to_page(
/*========================*/
	hash_table_t*	table,	/*!< in: hash table */
	ulint		fold,	/*!< in: fold value */
	const page_t*	page)	/*!< in: buffer page */
{
	ha_node_t*	node;

	ut_ad(table);
	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
	ASSERT_HASH_MUTEX_OWN(table, fold);

	node = ha_chain_get_first(table, fold);

	while (node) {
		if (page_align(ha_node_get_data(node)) == page) {

			/* Remove the hash node */

			ha_delete_hash_node(table, node);

			/* Start again from the first node in the chain
			because the deletion may compact the heap of
			nodes and move other nodes! */

			node = ha_chain_get_first(table, fold);
		} else {
			node = ha_chain_get_next(node);
		}
	}
#ifdef UNIV_DEBUG
	/* Check that all nodes really got deleted */

	node = ha_chain_get_first(table, fold);

	while (node) {
		ut_a(page_align(ha_node_get_data(node)) != page);

		node = ha_chain_get_next(node);
	}
#endif
}

/*************************************************************//**
Validates a given range of the cells in hash table.
@return	TRUE if ok */
UNIV_INTERN
ibool
ha_validate(
/*========*/
	hash_table_t*	table,		/*!< in: hash table */
	ulint		start_index,	/*!< in: start index */
	ulint		end_index)	/*!< in: end index */
{
	hash_cell_t*	cell;
	ha_node_t*	node;
	ibool		ok	= TRUE;
	ulint		i;

	ut_ad(table);
	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
	ut_a(start_index <= end_index);
	ut_a(start_index < hash_get_n_cells(table));
	ut_a(end_index < hash_get_n_cells(table));

	for (i = start_index; i <= end_index; i++) {

		cell = hash_get_nth_cell(table, i);

		node = cell->node;

		while (node) {
			if (hash_calc_hash(node->fold, table) != i) {
				ut_print_timestamp(stderr);
				fprintf(stderr,
					"InnoDB: Error: hash table node"
					" fold value %lu does not\n"
					"InnoDB: match the cell number %lu.\n",
					(ulong) node->fold, (ulong) i);

				ok = FALSE;
			}

			node = node->next;
		}
	}

	return(ok);
}

/*************************************************************//**
Prints info of a hash table. */
UNIV_INTERN
void
ha_print_info(
/*==========*/
	FILE*		file,	/*!< in: file where to print */
	hash_table_t*	table)	/*!< in: hash table */
{
#ifdef UNIV_DEBUG
/* Some of the code here is disabled for performance reasons in production
builds, see http://bugs.mysql.com/36941 */
#define PRINT_USED_CELLS
#endif /* UNIV_DEBUG */

#ifdef PRINT_USED_CELLS
	hash_cell_t*	cell;
	ulint		cells	= 0;
	ulint		i;
#endif /* PRINT_USED_CELLS */
	ulint		n_bufs;

	ut_ad(table);
	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
#ifdef PRINT_USED_CELLS
	for (i = 0; i < hash_get_n_cells(table); i++) {

		cell = hash_get_nth_cell(table, i);

		if (cell->node) {

			cells++;
		}
	}
#endif /* PRINT_USED_CELLS */

	fprintf(file, "Hash table size %lu",
		(ulong) hash_get_n_cells(table));

#ifdef PRINT_USED_CELLS
	fprintf(file, ", used cells %lu", (ulong) cells);
#endif /* PRINT_USED_CELLS */

	if (table->heaps == NULL && table->heap != NULL) {

		/* This calculation is intended for the adaptive hash
		index: how many buffer frames we have reserved? */

		n_bufs = UT_LIST_GET_LEN(table->heap->base) - 1;

		if (table->heap->free_block) {
			n_bufs++;
		}

		fprintf(file, ", node heap has %lu buffer(s)\n",
			(ulong) n_bufs);
	}
}
#endif /* !UNIV_HOTBACKUP */