MDEV-22871: Clean up hash_table_t

HASH_TABLE_SYNC_MUTEX was kind-of used for the adaptive hash index,
even though that hash table is already protected by btr_search_latches[].

HASH_TABLE_SYNC_RWLOCK was only being used for buf_pool.page_hash.
It is cleaner to decouple that synchronization from hash_table_t,
and move it to the actual user.

buf_pool_t::page_hash_latches[]: Synchronization for buf_pool.page_hash.

LATCH_ID_HASH_TABLE_MUTEX: Remove.

hash_table_t::sync_obj, hash_table_t::n_sync_obj: Remove.

hash_table_t::type, hash_table_sync_t: Remove.

HASH_ASSERT_OWN(), hash_get_mutex(), hash_get_nth_mutex(): Remove.

ib_recreate(): Merge to the only caller, buf_pool_resize_hash().

ib_create(): Merge to the callers.

ha_clear(): Merge to the only caller buf_pool_t::close().

buf_pool_t::create(): Merge the ib_create() and
hash_create_sync_obj() invocations.

ha_insert_for_fold_func(): Clarify an assertion.

buf_pool_t::page_hash_lock(): Simplify the logic.

hash_assert_can_search(), hash_assert_can_modify(): Remove.
These predicates were only being invoked for the adaptive hash index,
while they only are effective for buf_pool.page_hash.

HASH_DELETE_AND_COMPACT(): Merge to ha_delete_hash_node().

hash_get_sync_obj_index(): Remove.

hash_table_t::heaps[], hash_get_nth_heap(): Remove. It was actually unused!

hash_get_heap(): Remove. It was only used in ha_delete_hash_node(),
where we always use hash_table_t::heap.

hash_table_t::calc_hash(): Replaces hash_calc_hash().

16 files changed, 164 insertions, 808 deletions

diff --git a/storage/innobase/btr/btr0sea.cc b/storage/innobase/btr/btr0sea.cc
index 80003fe6abc..2d1f9100f32 100644
--- a/storage/innobase/btr/btr0sea.cc
+++ b/storage/innobase/btr/btr0sea.cc
@@ -387,9 +387,13 @@ void btr_search_enable(bool resize)
 		ut_malloc(sizeof(hash_table_t*) * btr_ahi_parts, mem_key_ahi));
 	for (ulint i = 0; i < btr_ahi_parts; ++i) {
 		btr_search_sys->hash_tables[i] =
-			ib_create((hash_size / btr_ahi_parts),
-				  LATCH_ID_HASH_TABLE_MUTEX,
-				  0, MEM_HEAP_FOR_BTR_SEARCH);
+			hash_create(hash_size / btr_ahi_parts);
+		btr_search_sys->hash_tables[i]->heap = mem_heap_create_typed(
+			std::min<ulong>(4096,
+					MEM_MAX_ALLOC_IN_BUF / 2
+					- MEM_BLOCK_HEADER_SIZE
+					- MEM_SPACE_NEEDED(0)),
+			MEM_HEAP_FOR_BTR_SEARCH);
 #if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
                 btr_search_sys->hash_tables[i]->adaptive = TRUE;
 #endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
diff --git a/storage/innobase/buf/buf0buf.cc b/storage/innobase/buf/buf0buf.cc
index e92d65b418b..1eb28db37a2 100644
--- a/storage/innobase/buf/buf0buf.cc
+++ b/storage/innobase/buf/buf0buf.cc
@@ -1523,11 +1523,10 @@ bool buf_pool_t::create()
   ut_a(srv_n_page_hash_locks != 0);
   ut_a(srv_n_page_hash_locks <= MAX_PAGE_HASH_LOCKS);
 
-  page_hash= ib_create(2 * curr_size,
-                         LATCH_ID_HASH_TABLE_RW_LOCK,
-                         srv_n_page_hash_locks, MEM_HEAP_FOR_PAGE_HASH);
-
-  ut_ad(!page_hash_old);
+  page_hash= hash_create(2 * curr_size);
+  for (auto i= srv_n_page_hash_locks; i--; )
+    rw_lock_create(hash_table_locks_key, &page_hash_latches[i],
+                   SYNC_BUF_PAGE_HASH);
   zip_hash= hash_create(2 * curr_size);
   last_printout_time= time(NULL);
 
@@ -1605,7 +1604,8 @@ void buf_pool_t::close()
 
   ut_free(chunks);
   chunks= nullptr;
-  ha_clear(page_hash);
+  for (auto i= srv_n_page_hash_locks; i--; )
+    rw_lock_free(&page_hash_latches[i]);
   hash_table_free(page_hash);
   hash_table_free(zip_hash);
 
@@ -1924,78 +1924,44 @@ inline bool buf_pool_t::withdraw_blocks()
 /** resize page_hash and zip_hash */
 static void buf_pool_resize_hash()
 {
-	hash_table_t*	new_hash_table;
-
-	ut_ad(buf_pool.page_hash_old == NULL);
-
-	/* recreate page_hash */
-	new_hash_table = ib_recreate(
-		buf_pool.page_hash, 2 * buf_pool.curr_size);
-
-	for (ulint i = 0; i < hash_get_n_cells(buf_pool.page_hash); i++) {
-		buf_page_t*	bpage;
-
-		bpage = static_cast<buf_page_t*>(
-			HASH_GET_FIRST(
-				buf_pool.page_hash, i));
-
-		while (bpage) {
-			buf_page_t*	prev_bpage = bpage;
-			ulint		fold;
-
-			ut_ad(bpage->in_page_hash);
-			bpage = static_cast<buf_page_t*>(
-				HASH_GET_NEXT(
-					hash, prev_bpage));
-
-			fold = prev_bpage->id().fold();
-
-			HASH_DELETE(buf_page_t, hash,
-				buf_pool.page_hash, fold,
-				prev_bpage);
-
-			HASH_INSERT(buf_page_t, hash,
-				new_hash_table, fold,
-				prev_bpage);
-		}
-	}
-
-	buf_pool.page_hash_old = buf_pool.page_hash;
-	buf_pool.page_hash = new_hash_table;
-
-	/* recreate zip_hash */
-	new_hash_table = hash_create(2 * buf_pool.curr_size);
-
-	for (ulint i = 0; i < hash_get_n_cells(buf_pool.zip_hash); i++) {
-		buf_page_t*	bpage;
-
-		bpage = static_cast<buf_page_t*>(
-			HASH_GET_FIRST(buf_pool.zip_hash, i));
+  hash_table_t *new_hash_table= hash_create(2 * buf_pool.curr_size);
 
-		while (bpage) {
-			buf_page_t*	prev_bpage = bpage;
-			ulint		fold;
-
-			bpage = static_cast<buf_page_t*>(
-				HASH_GET_NEXT(
-					hash, prev_bpage));
+  for (ulint i= 0; i < hash_get_n_cells(buf_pool.page_hash); i++)
+  {
+    while (buf_page_t *bpage= static_cast<buf_page_t*>
+           (HASH_GET_FIRST(buf_pool.page_hash, i)))
+    {
+      buf_page_t *prev_bpage= bpage;
+      ut_ad(bpage->in_page_hash);
+      bpage= static_cast<buf_page_t*>(HASH_GET_NEXT(hash, prev_bpage));
+      const ulint fold= prev_bpage->id().fold();
+      HASH_DELETE(buf_page_t, hash, buf_pool.page_hash, fold, prev_bpage);
+      HASH_INSERT(buf_page_t, hash, new_hash_table, fold, prev_bpage);
+    }
+  }
 
-			fold = BUF_POOL_ZIP_FOLD(
-				reinterpret_cast<buf_block_t*>(
-					prev_bpage));
+  std::swap(buf_pool.page_hash->array, new_hash_table->array);
+  buf_pool.page_hash->n_cells= new_hash_table->n_cells;
+  hash_table_free(new_hash_table);
 
-			HASH_DELETE(buf_page_t, hash,
-				buf_pool.zip_hash, fold,
-				prev_bpage);
+  /* recreate zip_hash */
+  new_hash_table= hash_create(2 * buf_pool.curr_size);
 
-			HASH_INSERT(buf_page_t, hash,
-				new_hash_table, fold,
-				prev_bpage);
-		}
-	}
+  for (ulint i= 0; i < hash_get_n_cells(buf_pool.zip_hash); i++)
+  {
+    while (buf_page_t *bpage= static_cast<buf_page_t*>
+           (HASH_GET_FIRST(buf_pool.zip_hash, i)))
+    {
+      buf_page_t *prev_bpage= bpage;
+      bpage= static_cast<buf_page_t*>(HASH_GET_NEXT(hash, prev_bpage));
+      const ulint fold= BUF_POOL_ZIP_FOLD_BPAGE(prev_bpage);
+      HASH_DELETE(buf_page_t, hash, buf_pool.zip_hash, fold, prev_bpage);
+      HASH_INSERT(buf_page_t, hash, new_hash_table, fold, prev_bpage);
+    }
+  }
 
-	hash_table_free(buf_pool.zip_hash);
-	buf_pool.zip_hash = new_hash_table;
+  hash_table_free(buf_pool.zip_hash);
+  buf_pool.zip_hash= new_hash_table;
 }
 
 
@@ -2162,8 +2128,10 @@ withdraw_retry:
 	/* Indicate critical path */
 	resizing.store(true, std::memory_order_relaxed);
 
-	mutex_enter(&mutex);
-	page_hash_lock_all();
+  mutex_enter(&mutex);
+  for (auto i= srv_n_page_hash_locks; i--; )
+    rw_lock_x_lock(&page_hash_latches[i]);
+
 	chunk_t::map_reg = UT_NEW_NOKEY(chunk_t::map());
 
 	/* add/delete chunks */
@@ -2312,13 +2280,9 @@ calc_buf_pool_size:
 		ib::info() << "hash tables were resized";
 	}
 
-	page_hash_unlock_all();
-	mutex_exit(&mutex);
-
-	if (page_hash_old != NULL) {
-		hash_table_free(page_hash_old);
-		page_hash_old = NULL;
-	}
+  mutex_exit(&mutex);
+  for (auto i= srv_n_page_hash_locks; i--; )
+    rw_lock_x_unlock(&page_hash_latches[i]);
 
 	UT_DELETE(chunk_map_old);
 
diff --git a/storage/innobase/ha/ha0ha.cc b/storage/innobase/ha/ha0ha.cc
index f73de63a97a..f0b5fb672cd 100644
--- a/storage/innobase/ha/ha0ha.cc
+++ b/storage/innobase/ha/ha0ha.cc
@@ -32,166 +32,6 @@ Created 8/22/1994 Heikki Tuuri
 #include "btr0sea.h"
 #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 */
-hash_table_t*
-ib_create(
-/*======*/
-	ulint		n,	/*!< in: number of array cells */
-	latch_id_t	id,	/*!< in: latch ID */
-	ulint		n_sync_obj,
-				/*!< in: number of mutexes to protect the
-				hash table: must be a power of 2, or 0 */
-	ulint		type)	/*!< in: type of datastructure for which
-				MEM_HEAP_FOR_PAGE_HASH */
-{
-	hash_table_t*	table;
-
-	ut_a(type == MEM_HEAP_FOR_BTR_SEARCH
-	     || type == MEM_HEAP_FOR_PAGE_HASH);
-
-	ut_ad(ut_is_2pow(n_sync_obj));
-	table = hash_create(n);
-
-	/* Creating MEM_HEAP_BTR_SEARCH type heaps can potentially fail,
-	but in practise it never should in this case, hence the asserts. */
-
-	if (n_sync_obj == 0) {
-		table->heap = mem_heap_create_typed(
-			std::min<ulong>(
-				4096,
-				MEM_MAX_ALLOC_IN_BUF / 2
-				- MEM_BLOCK_HEADER_SIZE - MEM_SPACE_NEEDED(0)),
-			type);
-		ut_a(table->heap);
-
-		return(table);
-	}
-
-	if (type == MEM_HEAP_FOR_PAGE_HASH) {
-		/* We create a hash table protected by rw_locks for
-		buf_pool.page_hash. */
-		hash_create_sync_obj(
-			table, HASH_TABLE_SYNC_RW_LOCK, id, n_sync_obj);
-	} else {
-		hash_create_sync_obj(
-			table, HASH_TABLE_SYNC_MUTEX, id, n_sync_obj);
-	}
-
-	table->heaps = static_cast<mem_heap_t**>(
-		ut_malloc_nokey(n_sync_obj * sizeof(void*)));
-
-	for (ulint i = 0; i < n_sync_obj; i++) {
-		table->heaps[i] = mem_heap_create_typed(
-			std::min<ulong>(
-				4096,
-				MEM_MAX_ALLOC_IN_BUF / 2
-				- MEM_BLOCK_HEADER_SIZE - MEM_SPACE_NEEDED(0)),
-			type);
-		ut_a(table->heaps[i]);
-	}
-
-	return(table);
-}
-
-/** Recreate 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.
-The new cells are all cleared. The heaps are recreated.
-The sync objects are reused.
-@param[in,out]	table	hash table to be resuzed (to be freed later)
-@param[in]	n	number of array cells
-@return	resized new table */
-hash_table_t*
-ib_recreate(
-	hash_table_t*	table,
-	ulint		n)
-{
-	/* This function is for only page_hash for now */
-	ut_ad(table->type == HASH_TABLE_SYNC_RW_LOCK);
-	ut_ad(table->n_sync_obj > 0);
-
-	hash_table_t*	new_table = hash_create(n);
-
-	new_table->type = table->type;
-	new_table->n_sync_obj = table->n_sync_obj;
-	new_table->sync_obj = table->sync_obj;
-
-	for (ulint i = 0; i < table->n_sync_obj; i++) {
-		mem_heap_free(table->heaps[i]);
-	}
-	ut_free(table->heaps);
-
-	new_table->heaps = static_cast<mem_heap_t**>(
-		ut_malloc_nokey(new_table->n_sync_obj * sizeof(void*)));
-
-	for (ulint i = 0; i < new_table->n_sync_obj; i++) {
-		new_table->heaps[i] = mem_heap_create_typed(
-			std::min<ulong>(
-				4096,
-				MEM_MAX_ALLOC_IN_BUF / 2
-				- MEM_BLOCK_HEADER_SIZE - MEM_SPACE_NEEDED(0)),
-			MEM_HEAP_FOR_PAGE_HASH);
-		ut_a(new_table->heaps[i]);
-	}
-
-	return(new_table);
-}
-
-/*************************************************************//**
-Empties a hash table and frees the memory heaps. */
-void
-ha_clear(
-/*=====*/
-	hash_table_t*	table)	/*!< in, own: hash table */
-{
-	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
-#ifdef BTR_CUR_HASH_ADAPT
-	ut_ad(!table->adaptive || btr_search_own_all(RW_LOCK_X));
-#endif /* BTR_CUR_HASH_ADAPT */
-
-	for (ulint i = 0; i < table->n_sync_obj; i++) {
-		mem_heap_free(table->heaps[i]);
-	}
-
-	ut_free(table->heaps);
-
-	switch (table->type) {
-	case HASH_TABLE_SYNC_MUTEX:
-		for (ulint i = 0; i < table->n_sync_obj; ++i) {
-			mutex_destroy(&table->sync_obj.mutexes[i]);
-		}
-		ut_free(table->sync_obj.mutexes);
-		table->sync_obj.mutexes = NULL;
-		break;
-
-	case HASH_TABLE_SYNC_RW_LOCK:
-		for (ulint i = 0; i < table->n_sync_obj; ++i) {
-			rw_lock_free(&table->sync_obj.rw_locks[i]);
-		}
-
-		ut_free(table->sync_obj.rw_locks);
-		table->sync_obj.rw_locks = NULL;
-		break;
-
-	case HASH_TABLE_SYNC_NONE:
-		/* do nothing */
-		break;
-	}
-
-	table->n_sync_obj = 0;
-	table->type = HASH_TABLE_SYNC_NONE;
-
-
-	/* Clear the hash table. */
-	ulint	n = hash_get_n_cells(table);
-
-	for (ulint i = 0; i < n; i++) {
-		hash_get_nth_cell(table, i)->node = NULL;
-	}
-}
-
 #ifdef BTR_CUR_HASH_ADAPT
 # if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
 /** Maximum number of records in a page */
@@ -199,42 +39,6 @@ static const ulint MAX_N_POINTERS
 	= UNIV_PAGE_SIZE_MAX / REC_N_NEW_EXTRA_BYTES;
 # endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
 
-# ifdef UNIV_DEBUG
-/** Assert that the synchronization object in a hash operation involving
-possible change in the hash table is held in exclusive mode */
-void hash_assert_can_modify(hash_table_t *table, ulint fold)
-{
-  switch (table->type) {
-  case HASH_TABLE_SYNC_MUTEX:
-    ut_ad(mutex_own(hash_get_mutex(table, fold)));
-    return;
-  case HASH_TABLE_SYNC_RW_LOCK:
-    ut_ad(buf_pool.page_hash_lock_own_flagged(fold, RW_LOCK_FLAG_X));
-    return;
-  case HASH_TABLE_SYNC_NONE:
-    return;
-  }
-  ut_ad(0);
-}
-
-/** Assert that the synchronization object in a hash operation involving
-possible change in the hash table is held in share dor exclusive mode */
-void hash_assert_can_search(hash_table_t *table, ulint fold)
-{
-  switch (table->type) {
-  case HASH_TABLE_SYNC_MUTEX:
-    ut_ad(mutex_own(hash_get_mutex(table, fold)));
-    return;
-  case HASH_TABLE_SYNC_RW_LOCK:
-    ut_ad(buf_pool.page_hash_lock_own_flagged(fold, RW_LOCK_FLAG_X |
-                                              RW_LOCK_FLAG_S));
-    return;
-  case HASH_TABLE_SYNC_NONE:
-    return;
-  }
-}
-# endif
-
 /*************************************************************//**
 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
@@ -262,10 +66,10 @@ ha_insert_for_fold_func(
 	ut_ad(data);
 	ut_ad(table);
 	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
+	ut_ad(table->heap->type & MEM_HEAP_BTR_SEARCH);
 #if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
 	ut_a(block->frame == page_align(data));
 #endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
-	hash_assert_can_modify(table, fold);
 	ut_ad(btr_search_enabled);
 
 	hash = hash_calc_hash(fold, table);
@@ -296,16 +100,12 @@ ha_insert_for_fold_func(
 	}
 
 	/* We have to allocate a new chain node */
-
 	node = static_cast<ha_node_t*>(
-		mem_heap_alloc(hash_get_heap(table, fold), sizeof(ha_node_t)));
+		mem_heap_alloc(table->heap, 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);
 	}
 
@@ -342,10 +142,8 @@ ha_insert_for_fold_func(
 
 #ifdef UNIV_DEBUG
 /** Verify if latch corresponding to the hash table is x-latched
-@param[in]	table		hash table */
-static
-void
-ha_btr_search_latch_x_locked(const hash_table_t* table)
+@param table   hash table */
+void ha_btr_search_latch_x_locked(const hash_table_t* table)
 {
 	ulint	i;
 	for (i = 0; i < btr_ahi_parts; ++i) {
@@ -372,13 +170,53 @@ ha_delete_hash_node(
 	ut_d(ha_btr_search_latch_x_locked(table));
 	ut_ad(btr_search_enabled);
 #if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
-	if (table->adaptive) {
-		ut_a(del_node->block->frame == page_align(del_node->data));
-		ut_a(del_node->block->n_pointers-- < MAX_N_POINTERS);
-	}
+	ut_a(table->adaptive);
+	ut_a(del_node->block->frame == page_align(del_node->data));
+	ut_a(del_node->block->n_pointers-- < MAX_N_POINTERS);
 #endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
 
-	HASH_DELETE_AND_COMPACT(ha_node_t, next, table, del_node);
+	ha_node_t* node;
+
+	const ulint fold = del_node->fold;
+
+	HASH_DELETE(ha_node_t, next, table, fold, del_node);
+
+	ha_node_t* top_node = (ha_node_t*) mem_heap_get_top(table->heap,
+							    sizeof(ha_node_t));
+
+	/* If the node to remove is not the top node in the heap, compact the
+	heap of nodes by moving the top node in the place of del_node. */
+
+	if (del_node != top_node) {
+		/* Copy the top node in place of del_node */
+
+		*del_node = *top_node;
+
+		hash_cell_t* cell = hash_get_nth_cell(
+			table, hash_calc_hash(top_node->fold, table));
+
+		/* Look for the pointer to the top node, to update it */
+
+		if (cell->node == top_node) {
+			/* The top node is the first in the chain */
+			cell->node = del_node;
+		} else {
+			/* We have to look for the predecessor */
+			node = static_cast<ha_node_t*>(cell->node);
+
+			while (top_node != HASH_GET_NEXT(next, node)) {
+				node = static_cast<ha_node_t*>(
+					HASH_GET_NEXT(next, node));
+			}
+
+			/* Now we have the predecessor node */
+			node->next = del_node;
+		}
+	}
+
+	/* Free the space occupied by the top node */
+
+	mem_heap_free_top(table->heap, sizeof(ha_node_t));
 }
 
 /*********************************************************//**
@@ -400,7 +238,6 @@ ha_search_and_update_if_found_func(
 
 	ut_ad(table);
 	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
-	hash_assert_can_modify(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 */
@@ -444,8 +281,8 @@ ha_remove_all_nodes_to_page(
 
 	ut_ad(table);
 	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
-	hash_assert_can_modify(table, fold);
 	ut_ad(btr_search_enabled);
+	ut_d(ha_btr_search_latch_x_locked(table));
 
 	node = ha_chain_get_first(table, fold);
 
diff --git a/storage/innobase/ha/hash0hash.cc b/storage/innobase/ha/hash0hash.cc
index 17e443a8bc8..6a8c84a349d 100644
--- a/storage/innobase/ha/hash0hash.cc
+++ b/storage/innobase/ha/hash0hash.cc
@@ -28,47 +28,21 @@ Created 5/20/1997 Heikki Tuuri
 #include "mem0mem.h"
 #include "sync0sync.h"
 
-/*************************************************************//**
-Creates a hash table with >= n array cells. The actual number of cells is
-chosen to be a prime number slightly bigger than n.
-@return own: created table */
-hash_table_t*
-hash_create(
-/*========*/
-	ulint	n)	/*!< in: number of array cells */
+/**
+Create a hash table.
+@param n   the minimum number of hash array elements
+@return created table (with n_cells being a prime, at least n) */
+hash_table_t *hash_create(ulint n)
 {
-	hash_cell_t*	array;
-	ulint		prime;
-	hash_table_t*	table;
-
-	prime = ut_find_prime(n);
-
-	table = static_cast<hash_table_t*>(
-		ut_malloc_nokey(sizeof(hash_table_t)));
-
-	array = static_cast<hash_cell_t*>(
-		ut_malloc_nokey(sizeof(hash_cell_t) * prime));
-
-	/* The default type of hash_table is HASH_TABLE_SYNC_NONE i.e.:
-	the caller is responsible for access control to the table. */
-	table->type = HASH_TABLE_SYNC_NONE;
-	table->array = array;
-	table->n_cells = prime;
-#ifdef BTR_CUR_HASH_ADAPT
-# if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
-	table->adaptive = FALSE;
-# endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
-#endif /* BTR_CUR_HASH_ADAPT */
-	table->n_sync_obj = 0;
-	table->sync_obj.mutexes = NULL;
-	table->heaps = NULL;
-	table->heap = NULL;
-	ut_d(table->magic_n = HASH_TABLE_MAGIC_N);
-
-	/* Initialize the cell array */
-	hash_table_clear(table);
-
-	return(table);
+  ulint prime= ut_find_prime(n);
+
+  hash_table_t *table= static_cast<hash_table_t*>
+    (ut_zalloc_nokey(sizeof *table));
+  table->array= static_cast<hash_cell_t*>(ut_zalloc_nokey(sizeof(hash_cell_t) *
+                                                          prime));
+  table->n_cells= prime;
+  ut_d(table->magic_n= HASH_TABLE_MAGIC_N);
+  return table;
 }
 
 /*************************************************************//**
@@ -83,58 +57,3 @@ hash_table_free(
 	ut_free(table->array);
 	ut_free(table);
 }
-
-/*************************************************************//**
-Creates a sync object array to protect a hash table.
-::sync_obj can be mutexes or rw_locks depening on the type of
-hash table. */
-void
-hash_create_sync_obj(
-/*=================*/
-	hash_table_t*		table,	/*!< in: hash table */
-	enum hash_table_sync_t	type,	/*!< in: HASH_TABLE_SYNC_MUTEX
-					or HASH_TABLE_SYNC_RW_LOCK */
-	latch_id_t		id,	/*!< in: latch ID */
-	ulint			n_sync_obj)/*!< in: number of sync objects,
-					must be a power of 2 */
-{
-	ut_a(n_sync_obj > 0);
-	ut_a(ut_is_2pow(n_sync_obj));
-	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
-
-	table->type = type;
-
-	switch (table->type) {
-	case HASH_TABLE_SYNC_MUTEX:
-		table->sync_obj.mutexes = static_cast<ib_mutex_t*>(
-			ut_malloc_nokey(n_sync_obj * sizeof(ib_mutex_t)));
-
-		for (ulint i = 0; i < n_sync_obj; i++) {
-			mutex_create(id, table->sync_obj.mutexes + i);
-		}
-
-		break;
-
-	case HASH_TABLE_SYNC_RW_LOCK: {
-
-		latch_level_t	level = sync_latch_get_level(id);
-
-		ut_a(level != SYNC_UNKNOWN);
-
-		table->sync_obj.rw_locks = static_cast<rw_lock_t*>(
-			ut_malloc_nokey(n_sync_obj * sizeof(rw_lock_t)));
-
-		for (ulint i = 0; i < n_sync_obj; i++) {
-			rw_lock_create(hash_table_locks_key,
-			     table->sync_obj.rw_locks + i, level);
-		}
-
-		break;
-	}
-
-	case HASH_TABLE_SYNC_NONE:
-		ut_error;
-	}
-
-	table->n_sync_obj = n_sync_obj;
-}
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index 00a226d5982..75ee30476f7 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -531,7 +531,6 @@ static PSI_mutex_info all_innodb_mutexes[] = {
 	PSI_KEY(fts_optimize_mutex),
 	PSI_KEY(fts_doc_id_mutex),
 	PSI_KEY(log_flush_order_mutex),
-	PSI_KEY(hash_table_mutex),
 	PSI_KEY(ibuf_bitmap_mutex),
 	PSI_KEY(ibuf_mutex),
 	PSI_KEY(ibuf_pessimistic_insert_mutex),
diff --git a/storage/innobase/include/buf0buf.h b/storage/innobase/include/buf0buf.h
index 4b77c6965ea..71d06db01e9 100644
--- a/storage/innobase/include/buf0buf.h
+++ b/storage/innobase/include/buf0buf.h
@@ -1612,43 +1612,40 @@ public:
   /** Get a page_hash latch. */
   rw_lock_t *hash_lock_get_low(ulint fold) const
   {
-    return page_hash->sync_obj.rw_locks +
-      hash_get_sync_obj_index(page_hash, fold);
+    return page_hash_latches +
+      ut_2pow_remainder(page_hash->calc_hash(fold),
+                        ulint{srv_n_page_hash_locks});
   }
-#ifdef UNIV_DEBUG
-  /** Check whether a page_hash latch is being held */
-  bool page_hash_lock_own_flagged(ulint fold, rw_lock_flags_t flagged) const
+private:
+  /** Get a page_hash latch. */
+  rw_lock_t *hash_lock_get_low(ulint fold, ulint n_cells) const
   {
-    return rw_lock_own_flagged(hash_lock_get_low(fold), flagged);
+    return page_hash_latches +
+      ut_2pow_remainder(ut_hash_ulint(fold, n_cells),
+                        ulint{srv_n_page_hash_locks});
   }
-#endif
+public:
 
   /** Acquire a page_hash bucket latch, tolerating concurrent resize()
   @tparam exclusive  whether the latch is to be acquired exclusively
   @param fold    hash bucket key */
   template<bool exclusive> rw_lock_t *page_hash_lock(ulint fold)
   {
-    rw_lock_t *latch= hash_lock_get_low(fold);
-    if (exclusive)
-      rw_lock_x_lock(latch);
-    else
-      rw_lock_s_lock(latch);
-    rw_lock_t *l;
-    while ((l= hash_lock_get_low(fold)) != latch)
+    for (;;)
     {
+      auto n_cells= page_hash->n_cells;
+      rw_lock_t *latch= hash_lock_get_low(fold, n_cells);
       if (exclusive)
-        rw_lock_x_unlock(latch);
+        rw_lock_x_lock(latch);
       else
-        rw_lock_s_unlock(latch);
-      /* FIXME: what if we resize() completes several times while we
-      are not holding any latch here? Is the latch guaranteed to be valid? */
+        rw_lock_s_lock(latch);
+      if (UNIV_LIKELY(n_cells == page_hash->n_cells))
+        return latch;
       if (exclusive)
-        rw_lock_x_lock(l);
+        rw_lock_x_unlock(latch);
       else
-        rw_lock_s_lock(l);
-      latch= l;
+        rw_lock_s_unlock(latch);
     }
-    return latch;
   }
 
   /** Look up a block descriptor.
@@ -1728,24 +1725,6 @@ public:
     return page_hash_get_locked<false,watch>(page_id, page_id.fold(), nullptr);
   }
 
-  /** Acquire exclusive latches on all page_hash buckets. */
-  void page_hash_lock_all() const
-  {
-    ut_ad(page_hash->magic_n == HASH_TABLE_MAGIC_N);
-    ut_ad(page_hash->type == HASH_TABLE_SYNC_RW_LOCK);
-    for (ulint i= 0; i < page_hash->n_sync_obj; i++)
-      rw_lock_x_lock(&page_hash->sync_obj.rw_locks[i]);
-  }
-  /** Release exclusive latches on all the page_hash buckets. */
-  void page_hash_unlock_all() const
-  {
-    ut_ad(page_hash->magic_n == HASH_TABLE_MAGIC_N);
-    ut_ad(page_hash->type == HASH_TABLE_SYNC_RW_LOCK);
-
-    for (ulint i = 0; i < page_hash->n_sync_obj; i++)
-      rw_lock_x_unlock(&page_hash->sync_obj.rw_locks[i]);
-  }
-
   /** Determine if a block is a sentinel for a buffer pool watch.
   @param bpage page descriptor
   @return whether bpage a sentinel for a buffer pool watch */
@@ -1894,10 +1873,11 @@ public:
 	Atomic_counter<uint32_t> read_ahead_area;
 
   /** Hash table of file pages (buf_page_t::in_file() holds),
-  indexed by page_id_t. Protected by both mutex and hash_lock_get(id). */
+  indexed by page_id_t. Protected by both mutex and page_hash_latches[]. */
   hash_table_t *page_hash;
-	hash_table_t*	page_hash_old;	/*!< old pointer to page_hash to be
-					freed after resizing buffer pool */
+  /** Latches protecting page_hash */
+  mutable rw_lock_t page_hash_latches[MAX_PAGE_HASH_LOCKS];
+
 	hash_table_t*	zip_hash;	/*!< hash table of buf_block_t blocks
 					whose frames are allocated to the
 					zip buddy system,
diff --git a/storage/innobase/include/ha0ha.h b/storage/innobase/include/ha0ha.h
index 5822fde2d04..3b3e511c9f5 100644
--- a/storage/innobase/include/ha0ha.h
+++ b/storage/innobase/include/ha0ha.h
@@ -19,7 +19,7 @@ this program; if not, write to the Free Software Foundation, Inc.,
 
 /**************************************************//**
 @file include/ha0ha.h
-The hash table with external chains
+The hash table interface for the adaptive hash index
 
 Created 8/18/1994 Heikki Tuuri
 *******************************************************/
@@ -81,41 +81,6 @@ updates the pointer to data if found.
 #endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
 #endif /* BTR_CUR_HASH_ADAPT */
 
-/*************************************************************//**
-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 */
-hash_table_t*
-ib_create(
-/*======*/
-	ulint		n,	/*!< in: number of array cells */
-	latch_id_t	id,	/*!< in: latch ID */
-	ulint		n_mutexes,/*!< in: number of mutexes to protect the
-				hash table: must be a power of 2, or 0 */
-	ulint		type);	/*!< in: type of datastructure for which
-				the memory heap is going to be used e.g.:
-				MEM_HEAP_FOR_BTR_SEARCH or
-				MEM_HEAP_FOR_PAGE_HASH */
-
-/** Recreate 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.
-The new cells are all cleared. The heaps are recreated.
-The sync objects are reused.
-@param[in,out]	table	hash table to be resuzed (to be freed later)
-@param[in]	n	number of array cells
-@return	resized new table */
-hash_table_t*
-ib_recreate(
-	hash_table_t*	table,
-	ulint		n);
-
-/*************************************************************//**
-Empties a hash table and frees the memory heaps. */
-void
-ha_clear(
-/*=====*/
-	hash_table_t*	table);	/*!< in, own: hash table */
-
 #ifdef BTR_CUR_HASH_ADAPT
 /*************************************************************//**
 Inserts an entry into a hash table. If an entry with the same fold number
@@ -207,20 +172,8 @@ struct ha_node_t {
 #endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
 	const rec_t*	data;	/*!< pointer to the data */
 };
-#endif /* BTR_CUR_HASH_ADAPT */
-
-#if defined UNIV_DEBUG && defined BTR_CUR_HASH_ADAPT
-/** Assert that the synchronization object in a hash operation involving
-possible change in the hash table is held in exclusive mode */
-void hash_assert_can_modify(hash_table_t *table, ulint fold);
-/** Assert that the synchronization object in a hash operation involving
-possible change in the hash table is held in share dor exclusive mode */
-void hash_assert_can_search(hash_table_t *table, ulint fold);
-#else /* UNIV_DEBUG */
-#define hash_assert_can_modify(t, f)
-#define hash_assert_can_search(t, f)
-#endif /* UNIV_DEBUG */
 
 #include "ha0ha.ic"
+#endif /* BTR_CUR_HASH_ADAPT */
 
 #endif
diff --git a/storage/innobase/include/ha0ha.ic b/storage/innobase/include/ha0ha.ic
index c83f4c35e81..57f21c02324 100644
--- a/storage/innobase/include/ha0ha.ic
+++ b/storage/innobase/include/ha0ha.ic
@@ -19,7 +19,7 @@ this program; if not, write to the Free Software Foundation, Inc.,
 
 /********************************************************************//**
 @file include/ha0ha.ic
-The hash table with external chains
+The hash table interface for the adaptive hash index
 
 Created 8/18/1994 Heikki Tuuri
 *************************************************************************/
@@ -110,7 +110,6 @@ ha_search_and_get_data(
 	hash_table_t*	table,	/*!< in: hash table */
 	ulint		fold)	/*!< in: folded value of the searched data */
 {
-	hash_assert_can_search(table, fold);
 	ut_ad(btr_search_enabled);
 
 	for (const ha_node_t* node = ha_chain_get_first(table, fold);
@@ -139,8 +138,6 @@ ha_search_with_data(
 {
 	ha_node_t*	node;
 
-	hash_assert_can_search(table, fold);
-
 	ut_ad(btr_search_enabled);
 
 	node = ha_chain_get_first(table, fold);
@@ -165,6 +162,12 @@ ha_delete_hash_node(
 	hash_table_t*	table,		/*!< in: hash table */
 	ha_node_t*	del_node);	/*!< in: node to be deleted */
 
+#ifdef UNIV_DEBUG
+/** Verify if latch corresponding to the hash table is x-latched
+@param table   hash table */
+void ha_btr_search_latch_x_locked(const hash_table_t* table);
+#endif /* UNIV_DEBUG */
+
 /*********************************************************//**
 Looks for an element when we know the pointer to the data, and deletes
 it from the hash table, if found.
@@ -179,7 +182,7 @@ ha_search_and_delete_if_found(
 {
 	ha_node_t*	node;
 
-	hash_assert_can_modify(table, fold);
+	ut_d(ha_btr_search_latch_x_locked(table));
 	ut_ad(btr_search_enabled);
 
 	node = ha_search_with_data(table, fold, data);
diff --git a/storage/innobase/include/hash0hash.h b/storage/innobase/include/hash0hash.h
index 94a5f3a02f7..29e242a540d 100644
--- a/storage/innobase/include/hash0hash.h
+++ b/storage/innobase/include/hash0hash.h
@@ -31,47 +31,19 @@ Created 5/20/1997 Heikki Tuuri
 #include "sync0rw.h"
 
 struct hash_table_t;
-struct hash_cell_t;
-
+struct hash_cell_t{
+	void*	node;	/*!< hash chain node, NULL if none */
+};
 typedef void*	hash_node_t;
 
 /* Fix Bug #13859: symbol collision between imap/mysql */
 #define hash_create hash0_create
 
-/* Differnt types of hash_table based on the synchronization
-method used for it. */
-enum hash_table_sync_t {
-	HASH_TABLE_SYNC_NONE = 0,	/*!< Don't use any internal
-					synchronization objects for
-					this hash_table. */
-	HASH_TABLE_SYNC_MUTEX,		/*!< Use mutexes to control
-					access to this hash_table. */
-	HASH_TABLE_SYNC_RW_LOCK		/*!< Use rw_locks to control
-					access to this hash_table. */
-};
-
-/*************************************************************//**
-Creates a hash table with >= n array cells. The actual number
-of cells is chosen to be a prime number slightly bigger than n.
-@return own: created table */
-hash_table_t*
-hash_create(
-/*========*/
-	ulint	n);	/*!< in: number of array cells */
-
-/*************************************************************//**
-Creates a sync object array array to protect a hash table.
-::sync_obj can be mutexes or rw_locks depening on the type of
-hash table. */
-void
-hash_create_sync_obj(
-/*=================*/
-	hash_table_t*		table,	/*!< in: hash table */
-	hash_table_sync_t	type,	/*!< in: HASH_TABLE_SYNC_MUTEX
-					or HASH_TABLE_SYNC_RW_LOCK */
-	latch_id_t		id,	/*!< in: mutex/rw_lock ID */
-	ulint			n_sync_obj);/*!< in: number of sync objects,
-					must be a power of 2 */
+/**
+Create a hash table.
+@param n   the minimum number of hash array elements
+@return created table (with n_cells being a prime, at least n) */
+hash_table_t *hash_create(ulint n);
 
 /*************************************************************//**
 Frees a hash table. */
@@ -79,20 +51,8 @@ void
 hash_table_free(
 /*============*/
 	hash_table_t*	table);	/*!< in, own: hash table */
-/**************************************************************//**
-Calculates the hash value from a folded value.
-@return hashed value */
-UNIV_INLINE
-ulint
-hash_calc_hash(
-/*===========*/
-	ulint		fold,	/*!< in: folded value */
-	hash_table_t*	table);	/*!< in: hash table */
-/********************************************************************//**
-Assert that the mutex for the table is held */
-#define HASH_ASSERT_OWN(TABLE, FOLD)				\
-	ut_ad((TABLE)->type != HASH_TABLE_SYNC_MUTEX		\
-	      || (mutex_own(hash_get_mutex((TABLE), FOLD))));
+
+#define hash_calc_hash(FOLD, TABLE) (TABLE)->calc_hash(FOLD)
 
 /*******************************************************************//**
 Inserts a struct to a hash table. */
@@ -102,8 +62,6 @@ do {\
 	hash_cell_t*	cell3333;\
 	TYPE*		struct3333;\
 \
-	HASH_ASSERT_OWN(TABLE, FOLD)\
-\
 	(DATA)->NAME = NULL;\
 \
 	cell3333 = hash_get_nth_cell(TABLE, hash_calc_hash(FOLD, TABLE));\
@@ -130,8 +88,6 @@ do {							\
 	hash_cell_t*	cell3333;			\
 	TYPE*		struct3333;			\
 							\
-	HASH_ASSERT_OWN(TABLE, FOLD)			\
-							\
 	(DATA)->NAME = NULL;				\
 							\
 	cell3333 = hash_get_nth_cell(TABLE, hash_calc_hash(FOLD, TABLE));\
@@ -163,8 +119,6 @@ do {\
 	hash_cell_t*	cell3333;\
 	TYPE*		struct3333;\
 \
-	HASH_ASSERT_OWN(TABLE, FOLD)\
-\
 	cell3333 = hash_get_nth_cell(TABLE, hash_calc_hash(FOLD, TABLE));\
 \
 	if (cell3333->node == DATA) {\
@@ -211,9 +165,6 @@ Gets the next struct in a hash chain, NULL if none. */
 Looks for a struct in a hash table. */
 #define HASH_SEARCH(NAME, TABLE, FOLD, TYPE, DATA, ASSERTION, TEST)\
 {\
-\
-	HASH_ASSERT_OWN(TABLE, FOLD)\
-\
 	(DATA) = (TYPE) HASH_GET_FIRST(TABLE, hash_calc_hash(FOLD, TABLE));\
 	HASH_ASSERT_VALID(DATA);\
 \
@@ -280,65 +231,6 @@ ulint
 hash_get_n_cells(
 /*=============*/
 	hash_table_t*	table);	/*!< in: table */
-/*******************************************************************//**
-Deletes a struct which is stored in the heap of the hash table, and compacts
-the heap. The fold value must be stored in the struct NODE in a field named
-'fold'. */
-
-#define HASH_DELETE_AND_COMPACT(TYPE, NAME, TABLE, NODE)\
-do {\
-	TYPE*		node111;\
-	TYPE*		top_node111;\
-	hash_cell_t*	cell111;\
-	ulint		fold111;\
-\
-	fold111 = (NODE)->fold;\
-\
-	HASH_DELETE(TYPE, NAME, TABLE, fold111, NODE);\
-\
-	top_node111 = (TYPE*) mem_heap_get_top(\
-				hash_get_heap(TABLE, fold111),\
-							sizeof(TYPE));\
-\
-	/* If the node to remove is not the top node in the heap, compact the\
-	heap of nodes by moving the top node in the place of NODE. */\
-\
-	if (NODE != top_node111) {\
-\
-		/* Copy the top node in place of NODE */\
-\
-		*(NODE) = *top_node111;\
-\
-		cell111 = hash_get_nth_cell(TABLE,\
-				hash_calc_hash(top_node111->fold, TABLE));\
-\
-		/* Look for the pointer to the top node, to update it */\
-\
-		if (cell111->node == top_node111) {\
-			/* The top node is the first in the chain */\
-\
-			cell111->node = NODE;\
-		} else {\
-			/* We have to look for the predecessor of the top\
-			node */\
-			node111 = static_cast<TYPE*>(cell111->node);\
-\
-			while (top_node111 != HASH_GET_NEXT(NAME, node111)) {\
-\
-				node111 = static_cast<TYPE*>(\
-					HASH_GET_NEXT(NAME, node111));\
-			}\
-\
-			/* Now we have the predecessor node */\
-\
-			node111->NAME = NODE;\
-		}\
-	}\
-\
-	/* Free the space occupied by the top node */\
-\
-	mem_heap_free_top(hash_get_heap(TABLE, fold111), sizeof(TYPE));\
-} while (0)
 
 /****************************************************************//**
 Move all hash table entries from OLD_TABLE to NEW_TABLE. */
@@ -367,59 +259,8 @@ do {\
 	}\
 } while (0)
 
-/************************************************************//**
-Gets the sync object index for a fold value in a hash table.
-@return index */
-UNIV_INLINE
-ulint
-hash_get_sync_obj_index(
-/*====================*/
-	hash_table_t*	table,	/*!< in: hash table */
-	ulint		fold);	/*!< in: fold */
-/************************************************************//**
-Gets the nth heap in a hash table.
-@return mem heap */
-UNIV_INLINE
-mem_heap_t*
-hash_get_nth_heap(
-/*==============*/
-	hash_table_t*	table,	/*!< in: hash table */
-	ulint		i);	/*!< in: index of the heap */
-/************************************************************//**
-Gets the heap for a fold value in a hash table.
-@return mem heap */
-UNIV_INLINE
-mem_heap_t*
-hash_get_heap(
-/*==========*/
-	hash_table_t*	table,	/*!< in: hash table */
-	ulint		fold);	/*!< in: fold */
-/************************************************************//**
-Gets the nth mutex in a hash table.
-@return mutex */
-UNIV_INLINE
-ib_mutex_t*
-hash_get_nth_mutex(
-/*===============*/
-	hash_table_t*	table,	/*!< in: hash table */
-	ulint		i);	/*!< in: index of the mutex */
-/************************************************************//**
-Gets the mutex for a fold value in a hash table.
-@return mutex */
-UNIV_INLINE
-ib_mutex_t*
-hash_get_mutex(
-/*===========*/
-	hash_table_t*	table,	/*!< in: hash table */
-	ulint		fold);	/*!< in: fold */
-
-struct hash_cell_t{
-	void*	node;	/*!< hash chain node, NULL if none */
-};
-
 /* The hash table structure */
 struct hash_table_t {
-	enum hash_table_sync_t	type;	/*<! type of hash_table. */
 #ifdef BTR_CUR_HASH_ADAPT
 # if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
 	ibool			adaptive;/* TRUE if this is the hash
@@ -429,31 +270,13 @@ struct hash_table_t {
 #endif /* BTR_CUR_HASH_ADAPT */
 	ulint			n_cells;/* number of cells in the hash table */
 	hash_cell_t*		array;	/*!< pointer to cell array */
-
-	ulint			n_sync_obj;/* if sync_objs != NULL, then
-					the number of either the number
-					of mutexes or the number of
-					rw_locks depending on the type.
-					Must be a power of 2 */
-	union {
-		ib_mutex_t*	mutexes;/* NULL, or an array of mutexes
-					used to protect segments of the
-					hash table */
-		rw_lock_t*	rw_locks;/* NULL, or an array of rw_locks
-					used to protect segments of the
-					buf_pool.page_hash */
-	} sync_obj;
-
-	mem_heap_t**		heaps;	/*!< if this is non-NULL, hash
-					chain nodes for external chaining
-					can be allocated from these memory
-					heaps; there are then n_mutexes
-					many of these heaps */
 	mem_heap_t*		heap;
 #ifdef UNIV_DEBUG
 	ulint			magic_n;
 # define HASH_TABLE_MAGIC_N	76561114
 #endif /* UNIV_DEBUG */
+
+  ulint calc_hash(ulint fold) const { return ut_hash_ulint(fold, n_cells); }
 };
 
 #include "hash0hash.ic"
diff --git a/storage/innobase/include/hash0hash.ic b/storage/innobase/include/hash0hash.ic
index cc717ec8559..63661b041fd 100644
--- a/storage/innobase/include/hash0hash.ic
+++ b/storage/innobase/include/hash0hash.ic
@@ -68,116 +68,3 @@ hash_get_n_cells(
 	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
 	return(table->n_cells);
 }
-
-/**************************************************************//**
-Calculates the hash value from a folded value.
-@return hashed value */
-UNIV_INLINE
-ulint
-hash_calc_hash(
-/*===========*/
-	ulint		fold,	/*!< in: folded value */
-	hash_table_t*	table)	/*!< in: hash table */
-{
-	ut_ad(table);
-	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
-	return(ut_hash_ulint(fold, table->n_cells));
-}
-
-/************************************************************//**
-Gets the sync object index for a fold value in a hash table.
-@return index */
-UNIV_INLINE
-ulint
-hash_get_sync_obj_index(
-/*====================*/
-	hash_table_t*	table,	/*!< in: hash table */
-	ulint		fold)	/*!< in: fold */
-{
-	ut_ad(table);
-	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
-	ut_ad(table->type != HASH_TABLE_SYNC_NONE);
-	ut_ad(ut_is_2pow(table->n_sync_obj));
-	return(ut_2pow_remainder(hash_calc_hash(fold, table),
-				 table->n_sync_obj));
-}
-
-/************************************************************//**
-Gets the nth heap in a hash table.
-@return mem heap */
-UNIV_INLINE
-mem_heap_t*
-hash_get_nth_heap(
-/*==============*/
-	hash_table_t*	table,	/*!< in: hash table */
-	ulint		i)	/*!< in: index of the heap */
-{
-	ut_ad(table);
-	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
-	ut_ad(table->type != HASH_TABLE_SYNC_NONE);
-	ut_ad(i < table->n_sync_obj);
-
-	return(table->heaps[i]);
-}
-
-/************************************************************//**
-Gets the heap for a fold value in a hash table.
-@return mem heap */
-UNIV_INLINE
-mem_heap_t*
-hash_get_heap(
-/*==========*/
-	hash_table_t*	table,	/*!< in: hash table */
-	ulint		fold)	/*!< in: fold */
-{
-	ulint	i;
-
-	ut_ad(table);
-	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
-
-	if (table->heap) {
-		return(table->heap);
-	}
-
-	i = hash_get_sync_obj_index(table, fold);
-
-	return(hash_get_nth_heap(table, i));
-}
-
-/************************************************************//**
-Gets the nth mutex in a hash table.
-@return mutex */
-UNIV_INLINE
-ib_mutex_t*
-hash_get_nth_mutex(
-/*===============*/
-	hash_table_t*	table,	/*!< in: hash table */
-	ulint		i)	/*!< in: index of the mutex */
-{
-	ut_ad(table);
-	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
-	ut_ad(table->type == HASH_TABLE_SYNC_MUTEX);
-	ut_ad(i < table->n_sync_obj);
-
-	return(table->sync_obj.mutexes + i);
-}
-
-/************************************************************//**
-Gets the mutex for a fold value in a hash table.
-@return mutex */
-UNIV_INLINE
-ib_mutex_t*
-hash_get_mutex(
-/*===========*/
-	hash_table_t*	table,	/*!< in: hash table */
-	ulint		fold)	/*!< in: fold */
-{
-	ulint	i;
-
-	ut_ad(table);
-	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
-
-	i = hash_get_sync_obj_index(table, fold);
-
-	return(hash_get_nth_mutex(table, i));
-}
diff --git a/storage/innobase/include/mem0mem.h b/storage/innobase/include/mem0mem.h
index ad4393ba51b..b7fd9c098a6 100644
--- a/storage/innobase/include/mem0mem.h
+++ b/storage/innobase/include/mem0mem.h
@@ -58,7 +58,6 @@ buffer pool; the latter method is used for very big heaps */
 
 /** Different type of heaps in terms of which datastructure is using them */
 #define MEM_HEAP_FOR_BTR_SEARCH		(MEM_HEAP_BTR_SEARCH | MEM_HEAP_BUFFER)
-#define MEM_HEAP_FOR_PAGE_HASH		(MEM_HEAP_DYNAMIC)
 #define MEM_HEAP_FOR_LOCK_HEAP		(MEM_HEAP_BUFFER)
 
 /** The following start size is used for the first block in the memory heap if
diff --git a/storage/innobase/include/sync0sync.h b/storage/innobase/include/sync0sync.h
index 8c45f415ef2..7eb8250b63d 100644
--- a/storage/innobase/include/sync0sync.h
+++ b/storage/innobase/include/sync0sync.h
@@ -62,7 +62,6 @@ extern mysql_pfs_key_t	fts_delete_mutex_key;
 extern mysql_pfs_key_t	fts_optimize_mutex_key;
 extern mysql_pfs_key_t	fts_doc_id_mutex_key;
 extern mysql_pfs_key_t	fts_pll_tokenize_mutex_key;
-extern mysql_pfs_key_t	hash_table_mutex_key;
 extern mysql_pfs_key_t	ibuf_bitmap_mutex_key;
 extern mysql_pfs_key_t	ibuf_mutex_key;
 extern mysql_pfs_key_t	ibuf_pessimistic_insert_mutex_key;
diff --git a/storage/innobase/include/sync0types.h b/storage/innobase/include/sync0types.h
index d7ba055c403..0aa1326509e 100644
--- a/storage/innobase/include/sync0types.h
+++ b/storage/innobase/include/sync0types.h
@@ -295,7 +295,6 @@ enum latch_id_t {
 	LATCH_ID_FTS_OPTIMIZE,
 	LATCH_ID_FTS_DOC_ID,
 	LATCH_ID_FTS_PLL_TOKENIZE,
-	LATCH_ID_HASH_TABLE_MUTEX,
 	LATCH_ID_IBUF_BITMAP,
 	LATCH_ID_IBUF,
 	LATCH_ID_IBUF_PESSIMISTIC_INSERT,
diff --git a/storage/innobase/srv/srv0srv.cc b/storage/innobase/srv/srv0srv.cc
index bf2d04acbf8..ab0bf1164ee 100644
--- a/storage/innobase/srv/srv0srv.cc
+++ b/storage/innobase/srv/srv0srv.cc
@@ -970,10 +970,7 @@ srv_printf_innodb_monitor(
 		const hash_table_t* table = btr_search_sys->hash_tables[i];
 
 		ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
-		/* this is only used for buf_pool.page_hash */
-		ut_ad(!table->heaps);
-		/* this is used for the adaptive hash index */
-		ut_ad(table->heap);
+		ut_ad(table->heap->type == MEM_HEAP_FOR_BTR_SEARCH);
 
 		const mem_heap_t* heap = table->heap;
 		/* The heap may change during the following call,
@@ -1140,10 +1137,7 @@ next:
 
 		ut_ad(ht);
 		ut_ad(ht->heap);
-		/* Multiple mutexes/heaps are currently never used for adaptive
-		hash index tables. */
-		ut_ad(!ht->n_sync_obj);
-		ut_ad(!ht->heaps);
+		ut_ad(ht->heap->type == MEM_HEAP_FOR_BTR_SEARCH);
 
 		mem_adaptive_hash += mem_heap_get_size(ht->heap)
 			+ ht->n_cells * sizeof(hash_cell_t);
diff --git a/storage/innobase/sync/sync0debug.cc b/storage/innobase/sync/sync0debug.cc
index 8ad3c4d0119..e370dc86f34 100644
--- a/storage/innobase/sync/sync0debug.cc
+++ b/storage/innobase/sync/sync0debug.cc
@@ -1294,9 +1294,6 @@ sync_latch_meta_init()
 	LATCH_ADD_MUTEX(FTS_PLL_TOKENIZE, SYNC_FTS_TOKENIZE,
 			fts_pll_tokenize_mutex_key);
 
-	LATCH_ADD_MUTEX(HASH_TABLE_MUTEX, SYNC_BUF_PAGE_HASH,
-			hash_table_mutex_key);
-
 	LATCH_ADD_MUTEX(IBUF_BITMAP, SYNC_IBUF_BITMAP_MUTEX,
 			ibuf_bitmap_mutex_key);
 
diff --git a/storage/innobase/sync/sync0sync.cc b/storage/innobase/sync/sync0sync.cc
index 068f15a77d8..85db39047ec 100644
--- a/storage/innobase/sync/sync0sync.cc
+++ b/storage/innobase/sync/sync0sync.cc
@@ -49,7 +49,6 @@ mysql_pfs_key_t	fts_delete_mutex_key;
 mysql_pfs_key_t	fts_optimize_mutex_key;
 mysql_pfs_key_t	fts_doc_id_mutex_key;
 mysql_pfs_key_t	fts_pll_tokenize_mutex_key;
-mysql_pfs_key_t	hash_table_mutex_key;
 mysql_pfs_key_t	ibuf_bitmap_mutex_key;
 mysql_pfs_key_t	ibuf_mutex_key;
 mysql_pfs_key_t	ibuf_pessimistic_insert_mutex_key;