MDEV-22871: Clean up btr_search_sys

btr_search_sys::parts[]: A single structure for the partitions of
the adaptive hash index. Replaces the 3 separate arrays:
btr_search_latches[], btr_search_sys->hash_tables,
btr_search_sys->hash_tables[i]->heap.

hash_table_t::heap, hash_table_t::adaptive: Remove.

ha0ha.cc: Remove. Move all code to btr0sea.cc.

17 files changed, 497 insertions, 892 deletions

diff --git a/storage/innobase/CMakeLists.txt b/storage/innobase/CMakeLists.txt
index 0cef6770181..ae5185e315e 100644
--- a/storage/innobase/CMakeLists.txt
+++ b/storage/innobase/CMakeLists.txt
@@ -56,7 +56,6 @@ SET(INNOBASE_SOURCES
 	fsp/fsp0space.cc
 	fsp/fsp0sysspace.cc
 	fut/fut0lst.cc
-	ha/ha0ha.cc
 	ha/ha0storage.cc
 	ha/hash0hash.cc
 	fts/fts0fts.cc
diff --git a/storage/innobase/btr/btr0cur.cc b/storage/innobase/btr/btr0cur.cc
index c99b737200d..9da9b90d246 100644
--- a/storage/innobase/btr/btr0cur.cc
+++ b/storage/innobase/btr/btr0cur.cc
@@ -3561,7 +3561,7 @@ fail_err:
 		ut_ad(index->is_instant());
 		ut_ad(flags == BTR_NO_LOCKING_FLAG);
 	} else {
-		rw_lock_t* ahi_latch = btr_get_search_latch(index);
+		rw_lock_t* ahi_latch = btr_search_sys.get_latch(*index);
 		if (!reorg && cursor->flag == BTR_CUR_HASH) {
 			btr_search_update_hash_node_on_insert(
 				cursor, ahi_latch);
@@ -3772,7 +3772,7 @@ btr_cur_pessimistic_insert(
 			ut_ad(!(flags & BTR_CREATE_FLAG));
 		} else {
 			btr_search_update_hash_on_insert(
-				cursor, btr_get_search_latch(index));
+				cursor, btr_search_sys.get_latch(*index));
 		}
 #endif /* BTR_CUR_HASH_ADAPT */
 		if (inherit && !(flags & BTR_NO_LOCKING_FLAG)) {
@@ -4274,7 +4274,7 @@ btr_cur_update_in_place(
 #ifdef BTR_CUR_HASH_ADAPT
 	{
 		rw_lock_t* ahi_latch = block->index
-			? btr_get_search_latch(index) : NULL;
+			? btr_search_sys.get_latch(*index) : NULL;
 		if (ahi_latch) {
 			/* TO DO: Can we skip this if none of the fields
 			index->search_info->curr_n_fields
diff --git a/storage/innobase/btr/btr0sea.cc b/storage/innobase/btr/btr0sea.cc
index 2d1f9100f32..bdaea6244ea 100644
--- a/storage/innobase/btr/btr0sea.cc
+++ b/storage/innobase/btr/btr0sea.cc
@@ -41,7 +41,6 @@ Created 2/17/1996 Heikki Tuuri
 #include "btr0btr.h"
 #include "ha0ha.h"
 #include "srv0mon.h"
-#include "sync0sync.h"
 
 /** Is search system enabled.
 Search system is protected by array of latches. */
@@ -57,25 +56,8 @@ ulint		btr_search_n_succ	= 0;
 ulint		btr_search_n_hash_fail	= 0;
 #endif /* UNIV_SEARCH_PERF_STAT */
 
-/** padding to prevent other memory update
-hotspots from residing on the same memory
-cache line as btr_search_latches */
-UNIV_INTERN byte		btr_sea_pad1[CACHE_LINE_SIZE];
-
-/** The latches protecting the adaptive search system: this latches protects the
-(1) positions of records on those pages where a hash index has been built.
-NOTE: It does not protect values of non-ordering fields within a record from
-being updated in-place! We can use fact (1) to perform unique searches to
-indexes. We will allocate the latches from dynamic memory to get it to the
-same DRAM page as other hotspot semaphores */
-rw_lock_t**	btr_search_latches;
-
-/** padding to prevent other memory update hotspots from residing on
-the same memory cache line */
-UNIV_INTERN byte		btr_sea_pad2[CACHE_LINE_SIZE];
-
 /** The adaptive hash index */
-btr_search_sys_t*	btr_search_sys;
+btr_search_sys_t btr_search_sys;
 
 /** If the number of records on the page divided by this parameter
 would have been successfully accessed using a hash index, the index
@@ -187,104 +169,23 @@ probable that, when have reserved the btr search system latch and we need to
 allocate a new node to the hash table, it will succeed. However, the check
 will not guarantee success.
 @param[in]	index	index handler */
-static
-void
-btr_search_check_free_space_in_heap(const dict_index_t* index)
+static void btr_search_check_free_space_in_heap(const dict_index_t *index)
 {
-	/* Note that we peek the value of heap->free_block without reserving
-	the latch: this is ok, because we will not guarantee that there will
-	be enough free space in the hash table. */
+  /* Note that we peek the value of heap->free_block without reserving
+  the latch: this is ok, because we will not guarantee that there will
+  be enough free space in the hash table. */
 
-	buf_block_t*	block = buf_block_alloc();
-	rw_lock_t*	latch = btr_get_search_latch(index);
-	hash_table_t*	table;
-	mem_heap_t*	heap;
+  buf_block_t *block= buf_block_alloc();
+  auto part= btr_search_sys.get_part(*index);
 
-	rw_lock_x_lock(latch);
+  rw_lock_x_lock(&part->latch);
 
-	if (!btr_search_enabled) {
-		goto func_exit;
-	}
-
-	table = btr_get_search_table(index);
-	heap = table->heap;
+  if (!btr_search_enabled || part->heap->free_block)
+    buf_block_free(block);
+  else
+    part->heap->free_block= block;
 
-	if (heap->free_block == NULL) {
-		heap->free_block = block;
-	} else {
-func_exit:
-		buf_block_free(block);
-	}
-
-	rw_lock_x_unlock(latch);
-}
-
-/** Creates and initializes the adaptive search system at a database start.
-@param[in]	hash_size	hash table size. */
-void btr_search_sys_create(ulint hash_size)
-{
-	/* Search System is divided into n parts.
-	Each part controls access to distinct set of hash buckets from
-	hash table through its own latch. */
-
-	/* Step-1: Allocate latches (1 per part). */
-	btr_search_latches = reinterpret_cast<rw_lock_t**>(
-		ut_malloc(sizeof(rw_lock_t*) * btr_ahi_parts, mem_key_ahi));
-
-	for (ulint i = 0; i < btr_ahi_parts; ++i) {
-
-		btr_search_latches[i] = reinterpret_cast<rw_lock_t*>(
-			ut_malloc(sizeof(rw_lock_t), mem_key_ahi));
-
-		rw_lock_create(btr_search_latch_key,
-			       btr_search_latches[i], SYNC_SEARCH_SYS);
-	}
-
-	/* Step-2: Allocate hash tablees. */
-	btr_search_sys = reinterpret_cast<btr_search_sys_t*>(
-		ut_malloc(sizeof(btr_search_sys_t), mem_key_ahi));
-
-	btr_search_sys->hash_tables = NULL;
-
-	if (btr_search_enabled) {
-		btr_search_enable();
-	}
-}
-
-/** Frees the adaptive search system at a database shutdown. */
-void btr_search_sys_free()
-{
-  if (!btr_search_sys)
-  {
-    ut_ad(!btr_search_latches);
-    return;
-  }
-
-  ut_ad(btr_search_sys);
-  ut_ad(btr_search_latches);
-
-  if (btr_search_sys->hash_tables)
-  {
-    for (ulint i= 0; i < btr_ahi_parts; ++i)
-    {
-      mem_heap_free(btr_search_sys->hash_tables[i]->heap);
-      hash_table_free(btr_search_sys->hash_tables[i]);
-    }
-    ut_free(btr_search_sys->hash_tables);
-  }
-
-  ut_free(btr_search_sys);
-  btr_search_sys= nullptr;
-
-  /* Free all latches. */
-  for (ulint i= 0; i < btr_ahi_parts; ++i)
-  {
-    rw_lock_free(btr_search_latches[i]);
-    ut_free(btr_search_latches[i]);
-  }
-
-  ut_free(btr_search_latches);
-  btr_search_latches= nullptr;
+  rw_lock_x_unlock(&part->latch);
 }
 
 /** Set index->ref_count = 0 on all indexes of a table.
@@ -351,12 +252,7 @@ void btr_search_disable()
 	buf_pool.clear_hash_index();
 
 	/* Clear the adaptive hash index. */
-	for (ulint i = 0; i < btr_ahi_parts; ++i) {
-		mem_heap_free(btr_search_sys->hash_tables[i]->heap);
-		hash_table_free(btr_search_sys->hash_tables[i]);
-	}
-	ut_free(btr_search_sys->hash_tables);
-	btr_search_sys->hash_tables = NULL;
+	btr_search_sys.clear();
 
 	btr_search_x_unlock_all();
 }
@@ -377,27 +273,13 @@ void btr_search_enable(bool resize)
 	btr_search_x_lock_all();
 	ulint hash_size = buf_pool_get_curr_size() / sizeof(void *) / 64;
 
-	if (btr_search_sys->hash_tables) {
+	if (btr_search_sys.parts[0].heap) {
 		ut_ad(btr_search_enabled);
 		btr_search_x_unlock_all();
 		return;
 	}
 
-	btr_search_sys->hash_tables = reinterpret_cast<hash_table_t**>(
-		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] =
-			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 */
-	}
+	btr_search_sys.alloc(hash_size);
 
 	btr_search_enabled = true;
 	btr_search_x_unlock_all();
@@ -581,6 +463,221 @@ btr_search_update_block_hash_info(btr_search_t* info, buf_block_t* block)
 	return(false);
 }
 
+#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
+/** Maximum number of records in a page */
+constexpr ulint MAX_N_POINTERS = UNIV_PAGE_SIZE_MAX / REC_N_NEW_EXTRA_BYTES;
+#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
+
+__attribute__((nonnull))
+/**
+Insert an entry into the 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.
+@param table hash table
+@param heap  memory heap
+@param fold  folded value of the record
+@param block buffer block containing the record
+@param data  the record
+@retval true on success
+@retval false if no more memory could be allocated */
+static bool ha_insert_for_fold(hash_table_t *table, mem_heap_t* heap,
+                               ulint fold,
+#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
+                               buf_block_t *block, /*!< buffer block of data */
+#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
+                               const rec_t *data)
+{
+#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
+  ut_a(block->frame == page_align(data));
+#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
+  ut_ad(btr_search_enabled);
+
+  ulint hash = hash_calc_hash(fold, table);
+  hash_cell_t *cell= hash_get_nth_cell(table, hash);
+
+  for (ha_node_t *prev= static_cast<ha_node_t*>(cell->node); prev;
+       prev= prev->next)
+  {
+    if (prev->fold == fold)
+    {
+#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
+      buf_block_t *prev_block= prev->block;
+      ut_a(prev_block->frame == page_align(prev->data));
+      ut_a(prev_block->n_pointers-- < MAX_N_POINTERS);
+      ut_a(block->n_pointers++ < MAX_N_POINTERS);
+
+      prev->block= block;
+#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
+      prev->data= data;
+      return true;
+    }
+  }
+
+  /* We have to allocate a new chain node */
+  ha_node_t *node= static_cast<ha_node_t*>(mem_heap_alloc(heap, sizeof *node));
+
+  if (!node)
+    return false;
+
+  ha_node_set_data(node, block, data);
+
+#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
+  ut_a(block->n_pointers++ < MAX_N_POINTERS);
+#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
+
+  node->fold= fold;
+  node->next= nullptr;
+
+  ha_node_t *prev= static_cast<ha_node_t*>(cell->node);
+  if (!prev)
+    cell->node= node;
+  else
+  {
+    while (prev->next)
+      prev= prev->next;
+    prev->next= node;
+  }
+  return true;
+}
+
+__attribute__((nonnull))
+/** Delete a record.
+@param table     hash table
+@param heap      memory heap
+@param del_node  record to be deleted */
+static void ha_delete_hash_node(hash_table_t *table, mem_heap_t *heap,
+                                ha_node_t *del_node)
+{
+  ut_ad(btr_search_enabled);
+#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
+  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 */
+
+  const ulint fold= del_node->fold;
+
+  HASH_DELETE(ha_node_t, next, table, fold, del_node);
+
+  ha_node_t *top= static_cast<ha_node_t*>(mem_heap_get_top(heap, sizeof *top));
+
+  if (del_node != top)
+  {
+    /* Compact the heap of nodes by moving the top in the place of del_node. */
+    *del_node= *top;
+    hash_cell_t *cell= hash_get_nth_cell(table, table->calc_hash(top->fold));
+
+    /* Look for the pointer to the top node, to update it */
+    if (cell->node == top)
+      /* The top node is the first in the chain */
+      cell->node= del_node;
+    else
+    {
+      /* We have to look for the predecessor */
+      ha_node_t *node= static_cast<ha_node_t*>(cell->node);
+
+      while (top != 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 occupied space */
+  mem_heap_free_top(heap, sizeof *top);
+}
+
+__attribute__((nonnull))
+/** Delete all pointers to a page.
+@param table     hash table
+@param heap      memory heap
+@param page      record to be deleted */
+static void ha_remove_all_nodes_to_page(hash_table_t *table, mem_heap_t *heap,
+                                        ulint fold, const page_t *page)
+{
+  for (ha_node_t *node= ha_chain_get_first(table, fold); node; )
+  {
+    if (page_align(ha_node_get_data(node)) == page)
+    {
+      ha_delete_hash_node(table, heap, node);
+      /* 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 */
+  for (ha_node_t *node= ha_chain_get_first(table, fold); node;
+       node= ha_chain_get_next(node))
+    ut_ad(page_align(ha_node_get_data(node)) != page);
+#endif /* UNIV_DEBUG */
+}
+
+/** Delete a record if found.
+@param table     hash table
+@param heap      memory heap for the hash bucket chain
+@param fold      folded value of the searched data
+@param data      pointer to the record
+@return whether the record was found */
+static bool ha_search_and_delete_if_found(hash_table_t *table,
+                                          mem_heap_t *heap,
+                                          ulint fold, const rec_t *data)
+{
+  if (ha_node_t *node= ha_search_with_data(table, fold, data))
+  {
+    ha_delete_hash_node(table, heap, node);
+    return true;
+  }
+
+  return false;
+}
+
+__attribute__((nonnull))
+/** Looks for an element when we know the pointer to the data and
+updates the pointer to data if found.
+@param table     hash table
+@param fold      folded value of the searched data
+@param data      pointer to the data
+@param new_data  new pointer to the data
+@return whether the element was found */
+static bool ha_search_and_update_if_found(hash_table_t *table, ulint fold,
+                                          const rec_t *data,
+#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
+                                          /** block containing new_data */
+                                          buf_block_t *new_block,
+#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
+                                          const rec_t *new_data)
+{
+#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
+  ut_a(new_block->frame == page_align(new_data));
+#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
+
+  if (!btr_search_enabled)
+    return false;
+
+  if (ha_node_t *node= ha_search_with_data(table, fold, data))
+  {
+#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
+    ut_a(node->block->n_pointers-- < MAX_N_POINTERS);
+    ut_a(new_block->n_pointers++ < MAX_N_POINTERS);
+    node->block= new_block;
+#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
+    node->data= new_data;
+
+    return true;
+  }
+
+  return false;
+}
+
+#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
+#else
+# define ha_insert_for_fold(t,h,f,b,d) ha_insert_for_fold(t,h,f,d)
+# define ha_search_and_update_if_found(table,fold,data,new_block,new_data) \
+	ha_search_and_update_if_found(table,fold,data,new_data)
+#endif
+
 /** Updates a hash node reference when it has been unsuccessfully used in a
 search which could have succeeded with the used hash parameters. This can
 happen because when building a hash index for a page, we do not check
@@ -615,8 +712,8 @@ btr_search_update_hash_ref(
 	ut_ad(block->page.id().space() == index->table->space_id);
 	ut_ad(index == cursor->index);
 	ut_ad(!dict_index_is_ibuf(index));
-	rw_lock_t* const latch = btr_get_search_latch(index);
-	rw_lock_x_lock(latch);
+	auto part = btr_search_sys.get_part(*index);
+	rw_lock_x_lock(&part->latch);
 	ut_ad(!block->index || block->index == index);
 
 	if (block->index
@@ -644,14 +741,13 @@ btr_search_update_hash_ref(
 			mem_heap_free(heap);
 		}
 
-		ha_insert_for_fold(btr_get_search_table(index), fold,
-				   block, rec);
+		ha_insert_for_fold(&part->table, heap, fold, block, rec);
 
 		MONITOR_INC(MONITOR_ADAPTIVE_HASH_ROW_ADDED);
 	}
 
 func_exit:
-	rw_lock_x_unlock(latch);
+	rw_lock_x_unlock(&part->latch);
 }
 
 /** Checks if a guessed position for a tree cursor is right. Note that if
@@ -926,7 +1022,8 @@ btr_search_guess_on_hash(
 	}
 
 	ut_ad(!index->is_ibuf());
-	ut_ad(!ahi_latch || ahi_latch == btr_get_search_latch(index));
+	ut_ad(!ahi_latch
+	      || ahi_latch == &btr_search_sys.get_part(*index)->latch);
 	ut_ad((latch_mode == BTR_SEARCH_LEAF)
 	      || (latch_mode == BTR_MODIFY_LEAF));
 	compile_time_assert(ulint{BTR_SEARCH_LEAF} == ulint{RW_S_LATCH});
@@ -959,11 +1056,11 @@ btr_search_guess_on_hash(
 	cursor->fold = fold;
 	cursor->flag = BTR_CUR_HASH;
 
-	rw_lock_t* use_latch = ahi_latch ? NULL : btr_get_search_latch(index);
+	auto part = btr_search_sys.get_part(*index);
 	const rec_t* rec;
 
-	if (use_latch) {
-		rw_lock_s_lock(use_latch);
+	if (!ahi_latch) {
+		rw_lock_s_lock(&part->latch);
 
 		if (!btr_search_enabled) {
 			goto fail;
@@ -974,12 +1071,12 @@ btr_search_guess_on_hash(
 	}
 
 	rec = static_cast<const rec_t*>(
-		ha_search_and_get_data(btr_get_search_table(index), fold));
+		ha_search_and_get_data(&part->table, fold));
 
 	if (!rec) {
-		if (use_latch) {
+		if (!ahi_latch) {
 fail:
-			rw_lock_s_unlock(use_latch);
+			rw_lock_s_unlock(&part->latch);
 		}
 
 		btr_search_failure(info, cursor);
@@ -988,7 +1085,7 @@ fail:
 
 	buf_block_t* block = buf_pool.block_from_ahi(rec);
 
-	if (use_latch) {
+	if (!ahi_latch) {
 		rw_lock_t* hash_lock = buf_pool.hash_lock_get(
 			block->page.id());
 		rw_lock_s_lock(hash_lock);
@@ -1032,7 +1129,7 @@ got_no_latch:
 
 		buf_pool.stat.n_page_gets++;
 
-		rw_lock_s_unlock(use_latch);
+		rw_lock_s_unlock(&part->latch);
 
 		buf_block_dbg_add_level(block, SYNC_TREE_NODE_FROM_HASH);
 		if (UNIV_UNLIKELY(fail)) {
@@ -1149,7 +1246,6 @@ void btr_search_drop_page_hash_index(buf_block_t* block)
 	ulint			i;
 	mem_heap_t*		heap;
 	rec_offs*		offsets;
-	rw_lock_t*		latch;
 
 retry:
 	/* This debug check uses a dirty read that could theoretically cause
@@ -1175,17 +1271,15 @@ retry:
 
 	const index_id_t	index_id
 		= btr_page_get_index_id(block->frame);
-	const ulint		ahi_slot
-		= ut_fold_ulint_pair(static_cast<ulint>(index_id),
-				     block->page.id().space())
-		% btr_ahi_parts;
-	latch = btr_search_latches[ahi_slot];
 
-	rw_lock_s_lock(latch);
+	auto part = btr_search_sys.get_part(index_id,
+					    block->page.id().space());
+
+	rw_lock_s_lock(&part->latch);
 	assert_block_ahi_valid(block);
 
 	if (!block->index || !btr_search_enabled) {
-		rw_lock_s_unlock(latch);
+		rw_lock_s_unlock(&part->latch);
 		return;
 	}
 
@@ -1225,7 +1319,7 @@ retry:
 	/* NOTE: The AHI fields of block must not be accessed after
 	releasing search latch, as the index page might only be s-latched! */
 
-	rw_lock_s_unlock(latch);
+	rw_lock_s_unlock(&part->latch);
 
 	ut_a(n_fields > 0 || n_bytes > 0);
 
@@ -1276,7 +1370,7 @@ next_rec:
 		mem_heap_free(heap);
 	}
 
-	rw_lock_x_lock(latch);
+	rw_lock_x_lock(&part->latch);
 
 	if (UNIV_UNLIKELY(!block->index)) {
 		/* Someone else has meanwhile dropped the hash index */
@@ -1292,17 +1386,15 @@ next_rec:
 		/* Someone else has meanwhile built a new hash index on the
 		page, with different parameters */
 
-		rw_lock_x_unlock(latch);
+		rw_lock_x_unlock(&part->latch);
 
 		ut_free(folds);
 		goto retry;
 	}
 
 	for (i = 0; i < n_cached; i++) {
-
-		ha_remove_all_nodes_to_page(
-			btr_search_sys->hash_tables[ahi_slot],
-			folds[i], page);
+		ha_remove_all_nodes_to_page(&part->table, part->heap,
+					    folds[i], page);
 	}
 
 	switch (index->search_info->ref_count--) {
@@ -1321,7 +1413,7 @@ next_rec:
 
 cleanup:
 	assert_block_ahi_valid(block);
-	rw_lock_x_unlock(latch);
+	rw_lock_x_unlock(&part->latch);
 
 	ut_free(folds);
 }
@@ -1397,7 +1489,6 @@ btr_search_build_page_hash_index(
 	ulint		n_recs;
 	ulint*		folds;
 	const rec_t**	recs;
-	ulint		i;
 	mem_heap_t*	heap		= NULL;
 	rec_offs	offsets_[REC_OFFS_NORMAL_SIZE];
 	rec_offs*	offsets		= offsets_;
@@ -1410,7 +1501,7 @@ btr_search_build_page_hash_index(
 	}
 
 	rec_offs_init(offsets_);
-	ut_ad(ahi_latch == btr_get_search_latch(index));
+	ut_ad(ahi_latch == &btr_search_sys.get_part(*index)->latch);
 	ut_ad(index);
 	ut_ad(block->page.id().space() == index->table->space_id);
 	ut_ad(!dict_index_is_ibuf(index));
@@ -1534,20 +1625,12 @@ btr_search_build_page_hash_index(
 
 	btr_search_check_free_space_in_heap(index);
 
-	hash_table_t*	table	= btr_get_search_table(index);
 	rw_lock_x_lock(ahi_latch);
 
 	if (!btr_search_enabled) {
 		goto exit_func;
 	}
 
-	table = btr_get_search_table(index);
-	if (block->index && ((block->curr_n_fields != n_fields)
-			     || (block->curr_n_bytes != n_bytes)
-			     || (block->curr_left_side != left_side))) {
-		goto exit_func;
-	}
-
 	/* This counter is decremented every time we drop page
 	hash index entries and is incremented here. Since we can
 	rebuild hash index for a page that is already hashed, we
@@ -1556,6 +1639,10 @@ btr_search_build_page_hash_index(
 	if (!block->index) {
 		assert_block_ahi_empty(block);
 		index->search_info->ref_count++;
+	} else if (block->curr_n_fields != n_fields
+		   || block->curr_n_bytes != n_bytes
+		   || block->curr_left_side != left_side) {
+		goto exit_func;
 	}
 
 	block->n_hash_helps = 0;
@@ -1565,9 +1652,13 @@ btr_search_build_page_hash_index(
 	block->curr_left_side = left_side;
 	block->index = index;
 
-	for (i = 0; i < n_cached; i++) {
-
-		ha_insert_for_fold(table, folds[i], block, recs[i]);
+	{
+		auto part = btr_search_sys.get_part(*index);
+		for (ulint i = 0; i < n_cached; i++) {
+			ha_insert_for_fold(&part->table, part->heap,
+					   folds[i], block, recs[i]);
+			MONITOR_INC(MONITOR_ADAPTIVE_HASH_ROW_ADDED);
+		}
 	}
 
 	MONITOR_INC(MONITOR_ADAPTIVE_HASH_PAGE_ADDED);
@@ -1589,8 +1680,8 @@ exit_func:
 void
 btr_search_info_update_slow(btr_search_t* info, btr_cur_t* cursor)
 {
-	rw_lock_t*	ahi_latch = btr_get_search_latch(cursor->index);
-
+	rw_lock_t*	ahi_latch = &btr_search_sys.get_part(*cursor->index)
+		->latch;
 	ut_ad(!rw_lock_own_flagged(ahi_latch,
 				   RW_LOCK_FLAG_X | RW_LOCK_FLAG_S));
 
@@ -1659,7 +1750,9 @@ btr_search_move_or_delete_hash_entries(
 	assert_block_ahi_valid(block);
 	assert_block_ahi_valid(new_block);
 
-	rw_lock_t* ahi_latch = index ? btr_get_search_latch(index) : NULL;
+	rw_lock_t* ahi_latch = index
+		? &btr_search_sys.get_part(*index)->latch
+		: nullptr;
 
 	if (new_block->index) {
 		btr_search_drop_page_hash_index(block);
@@ -1745,27 +1838,25 @@ void btr_search_update_hash_on_delete(btr_cur_t* cursor)
 		mem_heap_free(heap);
 	}
 
-	rw_lock_t* ahi_latch = btr_get_search_latch(index);
+	auto part = btr_search_sys.get_part(*index);
 
-	rw_lock_x_lock(ahi_latch);
+	rw_lock_x_lock(&part->latch);
 	assert_block_ahi_valid(block);
 
-	if (btr_search_enabled) {
-		hash_table_t* table = btr_get_search_table(index);
-		if (block->index) {
-			ut_a(block->index == index);
-
-			if (ha_search_and_delete_if_found(table, fold, rec)) {
-				MONITOR_INC(MONITOR_ADAPTIVE_HASH_ROW_REMOVED);
-			} else {
-				MONITOR_INC(MONITOR_ADAPTIVE_HASH_ROW_REMOVE_NOT_FOUND);
-			}
+	if (block->index && btr_search_enabled) {
+		ut_a(block->index == index);
 
-			assert_block_ahi_valid(block);
+		if (ha_search_and_delete_if_found(&part->table, part->heap,
+						  fold, rec)) {
+			MONITOR_INC(MONITOR_ADAPTIVE_HASH_ROW_REMOVED);
+		} else {
+			MONITOR_INC(MONITOR_ADAPTIVE_HASH_ROW_REMOVE_NOT_FOUND);
 		}
+
+		assert_block_ahi_valid(block);
 	}
 
-	rw_lock_x_unlock(ahi_latch);
+	rw_lock_x_unlock(&part->latch);
 }
 
 /** Updates the page hash index when a single record is inserted on a page.
@@ -1776,12 +1867,11 @@ void btr_search_update_hash_on_delete(btr_cur_t* cursor)
 void
 btr_search_update_hash_node_on_insert(btr_cur_t* cursor, rw_lock_t* ahi_latch)
 {
-	hash_table_t*	table;
 	buf_block_t*	block;
 	dict_index_t*	index;
 	rec_t*		rec;
 
-	ut_ad(ahi_latch == btr_get_search_latch(cursor->index));
+	ut_ad(ahi_latch == &btr_search_sys.get_part(*cursor->index)->latch);
 	ut_ad(!btr_search_own_any(RW_LOCK_S));
 	ut_ad(!btr_search_own_any(RW_LOCK_X));
 #ifdef MYSQL_INDEX_DISABLE_AHI
@@ -1820,10 +1910,9 @@ btr_search_update_hash_node_on_insert(btr_cur_t* cursor, rw_lock_t* ahi_latch)
 	    && (cursor->n_bytes == block->curr_n_bytes)
 	    && !block->curr_left_side) {
 
-		table = btr_get_search_table(index);
-
 		if (ha_search_and_update_if_found(
-			table, cursor->fold, rec, block,
+			&btr_search_sys.get_part(*cursor->index)->table,
+			cursor->fold, rec, block,
 			page_rec_get_next(rec))) {
 			MONITOR_INC(MONITOR_ADAPTIVE_HASH_ROW_UPDATED);
 		}
@@ -1847,7 +1936,7 @@ func_exit:
 void
 btr_search_update_hash_on_insert(btr_cur_t* cursor, rw_lock_t* ahi_latch)
 {
-	hash_table_t*	table;
+	btr_search_sys_t::partition* part;
 	buf_block_t*	block;
 	dict_index_t*	index;
 	const rec_t*	rec;
@@ -1863,7 +1952,7 @@ btr_search_update_hash_on_insert(btr_cur_t* cursor, rw_lock_t* ahi_latch)
 	rec_offs*	offsets		= offsets_;
 	rec_offs_init(offsets_);
 
-	ut_ad(ahi_latch == btr_get_search_latch(cursor->index));
+	ut_ad(ahi_latch == &btr_search_sys.get_part(*cursor->index)->latch);
 	ut_ad(page_is_leaf(btr_cur_get_page(cursor)));
 	ut_ad(!btr_search_own_any(RW_LOCK_S));
 	ut_ad(!btr_search_own_any(RW_LOCK_X));
@@ -1932,8 +2021,10 @@ btr_search_update_hash_on_insert(btr_cur_t* cursor, rw_lock_t* ahi_latch)
 				goto function_exit;
 			}
 
-			table = btr_get_search_table(index);
-			ha_insert_for_fold(table, ins_fold, block, ins_rec);
+			part = btr_search_sys.get_part(*index);
+			ha_insert_for_fold(&part->table, part->heap,
+					   ins_fold, block, ins_rec);
+			MONITOR_INC(MONITOR_ADAPTIVE_HASH_ROW_ADDED);
 		}
 
 		goto check_next_rec;
@@ -1948,14 +2039,17 @@ btr_search_update_hash_on_insert(btr_cur_t* cursor, rw_lock_t* ahi_latch)
 			if (!btr_search_enabled || !block->index) {
 				goto function_exit;
 			}
-			table = btr_get_search_table(index);
+			part = btr_search_sys.get_part(*index);
 		}
 
 		if (!left_side) {
-			ha_insert_for_fold(table, fold, block, rec);
+			ha_insert_for_fold(&part->table, part->heap,
+					   fold, block, rec);
 		} else {
-			ha_insert_for_fold(table, ins_fold, block, ins_rec);
+			ha_insert_for_fold(&part->table, part->heap,
+					   ins_fold, block, ins_rec);
 		}
+		MONITOR_INC(MONITOR_ADAPTIVE_HASH_ROW_ADDED);
 	}
 
 check_next_rec:
@@ -1969,10 +2063,12 @@ check_next_rec:
 				if (!btr_search_enabled || !block->index) {
 					goto function_exit;
 				}
-				table = btr_get_search_table(index);
+				part = btr_search_sys.get_part(*index);
 			}
 
-			ha_insert_for_fold(table, ins_fold, block, ins_rec);
+			ha_insert_for_fold(&part->table, part->heap,
+					   ins_fold, block, ins_rec);
+			MONITOR_INC(MONITOR_ADAPTIVE_HASH_ROW_ADDED);
 		}
 
 		goto function_exit;
@@ -1986,14 +2082,17 @@ check_next_rec:
 			if (!btr_search_enabled || !block->index) {
 				goto function_exit;
 			}
-			table = btr_get_search_table(index);
+			part = btr_search_sys.get_part(*index);
 		}
 
 		if (!left_side) {
-			ha_insert_for_fold(table, ins_fold, block, ins_rec);
+			ha_insert_for_fold(&part->table, part->heap,
+					   ins_fold, block, ins_rec);
 		} else {
-			ha_insert_for_fold(table, next_fold, block, next_rec);
+			ha_insert_for_fold(&part->table, part->heap,
+					   next_fold, block, next_rec);
 		}
+		MONITOR_INC(MONITOR_ADAPTIVE_HASH_ROW_ADDED);
 	}
 
 function_exit:
@@ -2007,6 +2106,31 @@ function_exit:
 }
 
 #if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
+__attribute__((nonnull))
+/** @return whether a range of the cells is valid */
+static bool ha_validate(const hash_table_t *table,
+                        ulint start_index, ulint end_index)
+{
+  ut_a(start_index <= end_index);
+  ut_a(end_index < table->n_cells);
+
+  bool ok= true;
+
+  for (ulint i= start_index; i <= end_index; i++)
+  {
+    for (auto node= static_cast<const ha_node_t*>(table->array[i].node); node;
+         node= node->next)
+    {
+      if (table->calc_hash(node->fold) != i) {
+        ib::error() << "Hash table node fold value " << node->fold
+		    << " does not match the cell number " << i;
+	ok= false;
+      }
+    }
+  }
+
+  return ok;
+}
 
 /** Validates the search system for given hash table.
 @param[in]	hash_table_id	hash table to validate
@@ -2037,8 +2161,9 @@ btr_search_hash_table_validate(ulint hash_table_id)
 
 	mutex_enter(&buf_pool.mutex);
 
-	cell_count = hash_get_n_cells(
-		btr_search_sys->hash_tables[hash_table_id]);
+	auto &part = btr_search_sys.parts[hash_table_id];
+
+	cell_count = hash_get_n_cells(&part.table);
 
 	for (i = 0; i < cell_count; i++) {
 		/* We release search latches every once in a while to
@@ -2059,8 +2184,7 @@ btr_search_hash_table_validate(ulint hash_table_id)
 
 			mutex_enter(&buf_pool.mutex);
 
-			ulint	curr_cell_count = hash_get_n_cells(
-				btr_search_sys->hash_tables[hash_table_id]);
+			ulint curr_cell_count = hash_get_n_cells(&part.table);
 
 			if (cell_count != curr_cell_count) {
 
@@ -2072,8 +2196,7 @@ btr_search_hash_table_validate(ulint hash_table_id)
 			}
 		}
 
-		node = (ha_node_t*) hash_get_nth_cell(
-			btr_search_sys->hash_tables[hash_table_id], i)->node;
+		node = (ha_node_t*) hash_get_nth_cell(&part.table, i)->node;
 
 		for (; node != NULL; node = node->next) {
 			const buf_block_t*	block
@@ -2169,8 +2292,7 @@ state_ok:
 
 			mutex_enter(&buf_pool.mutex);
 
-			ulint	curr_cell_count = hash_get_n_cells(
-				btr_search_sys->hash_tables[hash_table_id]);
+			ulint curr_cell_count = hash_get_n_cells(&part.table);
 
 			if (cell_count != curr_cell_count) {
 
@@ -2184,8 +2306,7 @@ state_ok:
 
 		ulint end_index = ut_min(i + chunk_size - 1, cell_count - 1);
 
-		if (!ha_validate(btr_search_sys->hash_tables[hash_table_id],
-				 i, end_index)) {
+		if (!ha_validate(&part.table, i, end_index)) {
 			ok = FALSE;
 		}
 	}
diff --git a/storage/innobase/buf/buf0buf.cc b/storage/innobase/buf/buf0buf.cc
index 1eb28db37a2..84e8bb0e1c6 100644
--- a/storage/innobase/buf/buf0buf.cc
+++ b/storage/innobase/buf/buf0buf.cc
@@ -1552,7 +1552,7 @@ bool buf_pool_t::create()
 
   chunk_t::map_ref= chunk_t::map_reg;
   buf_LRU_old_ratio_update(100 * 3 / 8, false);
-  btr_search_sys_create(srv_buf_pool_curr_size / sizeof(void*) / 64);
+  btr_search_sys_create();
   ut_ad(is_initialised());
   return false;
 }
diff --git a/storage/innobase/ha/ha0ha.cc b/storage/innobase/ha/ha0ha.cc
deleted file mode 100644
index f0b5fb672cd..00000000000
--- a/storage/innobase/ha/ha0ha.cc
+++ /dev/null
@@ -1,361 +0,0 @@
-/*****************************************************************************
-
-Copyright (c) 1994, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2020, MariaDB Corporation.
-
-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.,
-51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
-
-*****************************************************************************/
-
-/********************************************************************//**
-@file ha/ha0ha.cc
-The hash table with external chains
-
-Created 8/22/1994 Heikki Tuuri
-*************************************************************************/
-
-#include "ha0ha.h"
-
-#ifdef UNIV_DEBUG
-# include "buf0buf.h"
-#endif /* UNIV_DEBUG */
-#include "btr0sea.h"
-#include "page0page.h"
-
-#ifdef BTR_CUR_HASH_ADAPT
-# if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
-/** Maximum number of records in a page */
-static const ulint MAX_N_POINTERS
-	= UNIV_PAGE_SIZE_MAX / REC_N_NEW_EXTRA_BYTES;
-# endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
-
-/*************************************************************//**
-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. If btr_search_enabled is set to FALSE, we will only allow
-updating existing nodes, but no new node is allowed to be added.
-@return TRUE if succeed, FALSE if no more memory could be allocated */
-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 */
-	const rec_t*		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);
-	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 */
-	ut_ad(btr_search_enabled);
-
-	hash = hash_calc_hash(fold, table);
-
-	cell = hash_get_nth_cell(table, hash);
-
-	prev_node = static_cast<ha_node_t*>(cell->node);
-
-	while (prev_node != NULL) {
-		if (prev_node->fold == fold) {
-#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
-			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-- < MAX_N_POINTERS);
-				ut_a(block->n_pointers++ < MAX_N_POINTERS);
-			}
-
-			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 = static_cast<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 */
-		return(FALSE);
-	}
-
-	ha_node_set_data(node, block, data);
-
-#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
-	if (table->adaptive) {
-		ut_a(block->n_pointers++ < MAX_N_POINTERS);
-	}
-#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
-
-	node->fold = fold;
-
-	node->next = NULL;
-
-	prev_node = static_cast<ha_node_t*>(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);
-}
-
-#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)
-{
-	ulint	i;
-	for (i = 0; i < btr_ahi_parts; ++i) {
-		if (btr_search_sys->hash_tables[i] == table) {
-			break;
-		}
-	}
-
-	ut_ad(i < btr_ahi_parts);
-	ut_ad(rw_lock_own(btr_search_latches[i], RW_LOCK_X));
-}
-#endif /* UNIV_DEBUG */
-
-/***********************************************************//**
-Deletes a hash node. */
-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);
-	ut_d(ha_btr_search_latch_x_locked(table));
-	ut_ad(btr_search_enabled);
-#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
-	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 */
-
-	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));
-}
-
-/*********************************************************//**
-Looks for an element when we know the pointer to the data, and updates
-the pointer to data, if found.
-@return TRUE if found */
-ibool
-ha_search_and_update_if_found_func(
-/*===============================*/
-	hash_table_t*	table,	/*!< in/out: hash table */
-	ulint		fold,	/*!< in: folded value of the searched data */
-	const rec_t*	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 */
-	const rec_t*	new_data)/*!< in: new pointer to the data */
-{
-	ha_node_t*	node;
-
-	ut_ad(table);
-	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
-#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
-	ut_a(new_block->frame == page_align(new_data));
-#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
-
-	ut_d(ha_btr_search_latch_x_locked(table));
-
-	if (!btr_search_enabled) {
-		return(FALSE);
-	}
-
-	node = ha_search_with_data(table, fold, data);
-
-	if (node) {
-#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
-		if (table->adaptive) {
-			ut_a(node->block->n_pointers-- < MAX_N_POINTERS);
-			ut_a(new_block->n_pointers++ < MAX_N_POINTERS);
-		}
-
-		node->block = new_block;
-#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
-		node->data = new_data;
-
-		return(TRUE);
-	}
-
-	return(FALSE);
-}
-
-/*****************************************************************//**
-Removes from the chain determined by fold all nodes whose data pointer
-points to the page given. */
-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);
-	ut_ad(btr_search_enabled);
-	ut_d(ha_btr_search_latch_x_locked(table));
-
-	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 /* UNIV_DEBUG */
-}
-
-#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
-/*************************************************************//**
-Validates a given range of the cells in hash table.
-@return TRUE if ok */
-ibool
-ha_validate(
-/*========*/
-	hash_table_t*	table,		/*!< in: hash table */
-	ulint		start_index,	/*!< in: start index */
-	ulint		end_index)	/*!< in: end index */
-{
-	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++) {
-		ha_node_t*	node;
-		hash_cell_t*	cell;
-
-		cell = hash_get_nth_cell(table, i);
-
-		for (node = static_cast<ha_node_t*>(cell->node);
-		     node != 0;
-		     node = node->next) {
-
-			if (hash_calc_hash(node->fold, table) != i) {
-				ib::error() << "Hash table node fold value "
-					<< node->fold << " does not match the"
-					" cell number " << i << ".";
-
-				ok = FALSE;
-			}
-		}
-	}
-
-	return(ok);
-}
-#endif /* defined UNIV_AHI_DEBUG || defined UNIV_DEBUG */
-#endif /* BTR_CUR_HASH_ADAPT */
diff --git a/storage/innobase/ha/hash0hash.cc b/storage/innobase/ha/hash0hash.cc
index 6a8c84a349d..37e5bc4dea7 100644
--- a/storage/innobase/ha/hash0hash.cc
+++ b/storage/innobase/ha/hash0hash.cc
@@ -28,20 +28,23 @@ Created 5/20/1997 Heikki Tuuri
 #include "mem0mem.h"
 #include "sync0sync.h"
 
+/** Create the hash table.
+@param n  the lower bound of n_cells */
+void hash_table_t::create(ulint n)
+{
+  n_cells= ut_find_prime(n);
+  array= static_cast<hash_cell_t*>(ut_zalloc_nokey(n_cells * sizeof *array));
+}
+
 /**
 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)
 {
-  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);
+  table->create(n);
   return table;
 }
 
@@ -52,8 +55,6 @@ hash_table_free(
 /*============*/
 	hash_table_t*	table)	/*!< in, own: hash table */
 {
-	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
-
 	ut_free(table->array);
 	ut_free(table);
 }
diff --git a/storage/innobase/include/btr0sea.h b/storage/innobase/include/btr0sea.h
index a406676c6ed..e3de4926a57 100644
--- a/storage/innobase/include/btr0sea.h
+++ b/storage/innobase/include/btr0sea.h
@@ -30,13 +30,10 @@ Created 2/17/1996 Heikki Tuuri
 #include "dict0dict.h"
 #ifdef BTR_CUR_HASH_ADAPT
 #include "ha0ha.h"
+#include "sync0sync.h"
 
-/** Creates and initializes the adaptive search system at a database start.
-@param[in]	hash_size	hash table size. */
-void btr_search_sys_create(ulint hash_size);
-
-/** Frees the adaptive search system at a database shutdown. */
-void btr_search_sys_free();
+#define btr_search_sys_create() btr_search_sys.create()
+#define btr_search_sys_free() btr_search_sys.free()
 
 /** Disable the adaptive hash search system and empty the index. */
 void btr_search_disable();
@@ -162,19 +159,8 @@ static inline bool btr_search_own_any();
 /** Unlock all search latches from shared mode. */
 static inline void btr_search_s_unlock_all();
 
-/** Get the latch based on index attributes.
-A latch is selected from an array of latches using pair of index-id, space-id.
-@param[in]	index	index handler
-@return latch */
-static inline rw_lock_t* btr_get_search_latch(const dict_index_t* index);
-
-/** Get the hash-table based on index attributes.
-A table is selected from an array of tables using pair of index-id, space-id.
-@param[in]	index	index handler
-@return hash table */
-static inline hash_table_t* btr_get_search_table(const dict_index_t* index);
 #else /* BTR_CUR_HASH_ADAPT */
-# define btr_search_sys_create(size)
+# define btr_search_sys_create()
 # define btr_search_sys_free()
 # define btr_search_drop_page_hash_index(block)
 # define btr_search_s_lock_all(index)
@@ -259,31 +245,119 @@ struct btr_search_t{
 };
 
 #ifdef BTR_CUR_HASH_ADAPT
+/** The hash index system */
+struct btr_search_sys_t
+{
+  /** Partition of the hash table */
+  struct partition
+  {
+    /** latches protecting hash_table */
+    rw_lock_t latch;
+    /** mapping of dtuple_fold() to rec_t* in buf_block_t::frame */
+    hash_table_t table;
+    /** memory heap for table */
+    mem_heap_t *heap;
+
+    char pad[(CPU_LEVEL1_DCACHE_LINESIZE - sizeof(rw_lock_t) -
+              sizeof(hash_table_t) - sizeof(mem_heap_t)) &
+             (CPU_LEVEL1_DCACHE_LINESIZE - 1)];
+
+    void init()
+    {
+      memset((void*) this, 0, sizeof *this);
+      rw_lock_create(btr_search_latch_key, &latch, SYNC_SEARCH_SYS);
+    }
+
+    void alloc(ulint hash_size)
+    {
+      table.create(hash_size);
+      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);
+    }
+
+    void clear()
+    {
+      mem_heap_free(heap);
+      heap= nullptr;
+      ut_free(table.array);
+    }
+
+    void free()
+    {
+      rw_lock_free(&latch);
+      if (heap)
+        clear();
+    }
+  };
+
+  /** Partitions of the adaptive hash index */
+  partition *parts;
+
+  /** Get an adaptive hash index partition */
+  partition *get_part(index_id_t id, ulint space_id) const
+  {
+    return parts + ut_fold_ulint_pair(ulint(id), space_id) % btr_ahi_parts;
+  }
+
+  /** Get an adaptive hash index partition */
+  partition *get_part(const dict_index_t &index) const
+  {
+    ut_ad(index.table->space->id == index.table->space_id);
+    return get_part(ulint(index.id), index.table->space_id);
+  }
+
+  /** Get the search latch for the adaptive hash index partition */
+  rw_lock_t *get_latch(const dict_index_t &index) const
+  { return &get_part(index)->latch; }
+
+  /** Create and initialize at startup */
+  void create()
+  {
+    parts= static_cast<partition*>(ut_malloc(btr_ahi_parts * sizeof *parts,
+                                             mem_key_ahi));
+    for (ulong i= 0; i < btr_ahi_parts; ++i)
+      parts[i].init();
+    if (btr_search_enabled)
+      btr_search_enable();
+  }
+
+  void alloc(ulint hash_size)
+  {
+    hash_size/= btr_ahi_parts;
+    for (ulong i= 0; i < btr_ahi_parts; ++i)
+      parts[i].alloc(hash_size);
+  }
+
+  /** Clear when disabling the adaptive hash index */
+  void clear() { for (ulong i= 0; i < btr_ahi_parts; ++i) parts[i].clear(); }
+
+  /** Free at shutdown */
+  void free()
+  {
+    if (parts)
+      for (ulong i= 0; i < btr_ahi_parts; ++i)
+        parts[i].free();
+  }
+};
+
+/** The adaptive hash index */
+extern btr_search_sys_t btr_search_sys;
+
 /** @return number of leaf pages pointed to by the adaptive hash index */
 inline ulint dict_index_t::n_ahi_pages() const
 {
   if (!btr_search_enabled)
     return 0;
-  rw_lock_t *latch = btr_get_search_latch(this);
+  rw_lock_t *latch = &btr_search_sys.get_part(*this)->latch;
   rw_lock_s_lock(latch);
   ulint ref_count= search_info->ref_count;
   rw_lock_s_unlock(latch);
   return ref_count;
 }
 
-/** The hash index system */
-struct btr_search_sys_t{
-	hash_table_t**	hash_tables;	/*!< the adaptive hash tables,
-					mapping dtuple_fold values
-					to rec_t pointers on index pages */
-};
-
-/** Latches protecting access to adaptive hash index. */
-extern rw_lock_t**		btr_search_latches;
-
-/** The adaptive hash index */
-extern btr_search_sys_t*	btr_search_sys;
-
 #ifdef UNIV_SEARCH_PERF_STAT
 /** Number of successful adaptive hash index lookups */
 extern ulint	btr_search_n_succ;
diff --git a/storage/innobase/include/btr0sea.ic b/storage/innobase/include/btr0sea.ic
index 9db0084ce59..40eb5d86ead 100644
--- a/storage/innobase/include/btr0sea.ic
+++ b/storage/innobase/include/btr0sea.ic
@@ -88,7 +88,7 @@ btr_search_info_update(
 static inline void btr_search_x_lock_all()
 {
 	for (ulint i = 0; i < btr_ahi_parts; ++i) {
-		rw_lock_x_lock(btr_search_latches[i]);
+		rw_lock_x_lock(&btr_search_sys.parts[i].latch);
 	}
 }
 
@@ -96,7 +96,7 @@ static inline void btr_search_x_lock_all()
 static inline void btr_search_x_unlock_all()
 {
 	for (ulint i = 0; i < btr_ahi_parts; ++i) {
-		rw_lock_x_unlock(btr_search_latches[i]);
+		rw_lock_x_unlock(&btr_search_sys.parts[i].latch);
 	}
 }
 
@@ -104,7 +104,7 @@ static inline void btr_search_x_unlock_all()
 static inline void btr_search_s_lock_all()
 {
 	for (ulint i = 0; i < btr_ahi_parts; ++i) {
-		rw_lock_s_lock(btr_search_latches[i]);
+		rw_lock_s_lock(&btr_search_sys.parts[i].latch);
 	}
 }
 
@@ -112,7 +112,7 @@ static inline void btr_search_s_lock_all()
 static inline void btr_search_s_unlock_all()
 {
 	for (ulint i = 0; i < btr_ahi_parts; ++i) {
-		rw_lock_s_unlock(btr_search_latches[i]);
+		rw_lock_s_unlock(&btr_search_sys.parts[i].latch);
 	}
 }
 
@@ -124,7 +124,7 @@ static inline void btr_search_s_unlock_all()
 static inline bool btr_search_own_all(ulint mode)
 {
 	for (ulint i = 0; i < btr_ahi_parts; ++i) {
-		if (!rw_lock_own(btr_search_latches[i], mode)) {
+		if (!rw_lock_own(&btr_search_sys.parts[i].latch, mode)) {
 			return(false);
 		}
 	}
@@ -138,7 +138,7 @@ static inline bool btr_search_own_all(ulint mode)
 static inline bool btr_search_own_any(ulint mode)
 {
 	for (ulint i = 0; i < btr_ahi_parts; ++i) {
-		if (rw_lock_own(btr_search_latches[i], mode)) {
+		if (rw_lock_own(&btr_search_sys.parts[i].latch, mode)) {
 			return(true);
 		}
 	}
@@ -149,7 +149,7 @@ static inline bool btr_search_own_any(ulint mode)
 static inline bool btr_search_own_any()
 {
 	for (ulint i = btr_ahi_parts; i--; ) {
-		if (rw_lock_own_flagged(btr_search_latches[i],
+		if (rw_lock_own_flagged(&btr_search_sys.parts[i].latch,
 					RW_LOCK_FLAG_X | RW_LOCK_FLAG_S)) {
 			return true;
 		}
@@ -157,34 +157,4 @@ static inline bool btr_search_own_any()
 	return false;
 }
 #endif /* UNIV_DEBUG */
-
-/** Get the adaptive hash search index latch for a b-tree.
-@param[in]	index	b-tree index
-@return latch */
-static inline rw_lock_t* btr_get_search_latch(const dict_index_t* index)
-{
-	ut_ad(index != NULL);
-	ut_ad(!index->table->space
-	      || index->table->space->id == index->table->space_id);
-
-	ulint	ifold = ut_fold_ulint_pair(ulint(index->id),
-					   index->table->space_id);
-
-	return(btr_search_latches[ifold % btr_ahi_parts]);
-}
-
-/** Get the hash-table based on index attributes.
-A table is selected from an array of tables using pair of index-id, space-id.
-@param[in]	index	index handler
-@return hash table */
-static inline hash_table_t* btr_get_search_table(const dict_index_t* index)
-{
-	ut_ad(index != NULL);
-	ut_ad(index->table->space->id == index->table->space_id);
-
-	ulint	ifold = ut_fold_ulint_pair(ulint(index->id),
-					   index->table->space_id);
-
-	return(btr_search_sys->hash_tables[ifold % btr_ahi_parts]);
-}
 #endif /* BTR_CUR_HASH_ADAPT */
diff --git a/storage/innobase/include/buf0buf.h b/storage/innobase/include/buf0buf.h
index 71d06db01e9..6758e427c74 100644
--- a/storage/innobase/include/buf0buf.h
+++ b/storage/innobase/include/buf0buf.h
@@ -1131,7 +1131,7 @@ struct buf_block_t{
 	assigning block->index = NULL (and block->n_pointers = 0)
 	is allowed whenever btr_search_own_all(RW_LOCK_X).
 
-	Another exception is that ha_insert_for_fold_func() may
+	Another exception is that ha_insert_for_fold() may
 	decrement n_pointers without holding the appropriate latch
 	in btr_search_latches[]. Thus, n_pointers must be
 	protected by atomic memory access.
diff --git a/storage/innobase/include/ha0ha.h b/storage/innobase/include/ha0ha.h
index 3b3e511c9f5..561c322521e 100644
--- a/storage/innobase/include/ha0ha.h
+++ b/storage/innobase/include/ha0ha.h
@@ -43,125 +43,6 @@ ha_search_and_get_data(
 /*===================*/
 	hash_table_t*	table,	/*!< in: hash table */
 	ulint		fold);	/*!< in: folded value of the searched data */
-/*********************************************************//**
-Looks for an element when we know the pointer to the data and updates
-the pointer to data if found.
-@return TRUE if found */
-ibool
-ha_search_and_update_if_found_func(
-/*===============================*/
-	hash_table_t*	table,	/*!< in/out: hash table */
-	ulint		fold,	/*!< in: folded value of the searched data */
-	const rec_t*	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 */
-	const rec_t*	new_data);/*!< in: new pointer to the data */
-
-#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
-/** Looks for an element when we know the pointer to the data and
-updates the pointer to data if found.
-@param table in/out: hash table
-@param fold in: folded value of the searched data
-@param data in: pointer to the data
-@param new_block in: block containing new_data
-@param new_data in: new pointer to the data */
-# define ha_search_and_update_if_found(table,fold,data,new_block,new_data) \
-	ha_search_and_update_if_found_func(table,fold,data,new_block,new_data)
-#else /* UNIV_AHI_DEBUG || UNIV_DEBUG */
-/** Looks for an element when we know the pointer to the data and
-updates the pointer to data if found.
-@param table in/out: hash table
-@param fold in: folded value of the searched data
-@param data in: pointer to the data
-@param new_block ignored: block containing new_data
-@param new_data in: new pointer to the data */
-# define ha_search_and_update_if_found(table,fold,data,new_block,new_data) \
-	ha_search_and_update_if_found_func(table,fold,data,new_data)
-#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
-#endif /* BTR_CUR_HASH_ADAPT */
-
-#ifdef BTR_CUR_HASH_ADAPT
-/*************************************************************//**
-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 */
-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 */
-	const rec_t*	data);	/*!< in: data, must not be NULL */
-
-#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
-/**
-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
-@param t in: hash table
-@param f in: folded value of data
-@param b in: buffer block containing the data
-@param d in: data, must not be NULL */
-# define ha_insert_for_fold(t,f,b,d) 	do {		\
-	ha_insert_for_fold_func(t,f,b,d);		\
-	MONITOR_INC(MONITOR_ADAPTIVE_HASH_ROW_ADDED);	\
-} while(0)
-#else /* UNIV_AHI_DEBUG || UNIV_DEBUG */
-/**
-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
-@param t in: hash table
-@param f in: folded value of data
-@param b ignored: buffer block containing the data
-@param d in: data, must not be NULL */
-# define ha_insert_for_fold(t,f,b,d)	do {		\
-	ha_insert_for_fold_func(t,f,d);			\
-	MONITOR_INC(MONITOR_ADAPTIVE_HASH_ROW_ADDED);	\
-} while (0)
-#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
-
-/*********************************************************//**
-Looks for an element when we know the pointer to the data and deletes
-it from the hash table if found.
-@return TRUE if found */
-UNIV_INLINE
-ibool
-ha_search_and_delete_if_found(
-/*==========================*/
-	hash_table_t*	table,	/*!< in: hash table */
-	ulint		fold,	/*!< in: folded value of the searched data */
-	const rec_t*	data);	/*!< in: pointer to the data */
-
-/*****************************************************************//**
-Removes from the chain determined by fold all nodes whose data pointer
-points to the page given. */
-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 */
-#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
-/*************************************************************//**
-Validates a given range of the cells in hash table.
-@return TRUE if ok */
-ibool
-ha_validate(
-/*========*/
-	hash_table_t*	table,		/*!< in: hash table */
-	ulint		start_index,	/*!< in: start index */
-	ulint		end_index);	/*!< in: end index */
-#endif /* defined UNIV_AHI_DEBUG || defined UNIV_DEBUG */
 
 /** The hash table external chain node */
 struct ha_node_t {
diff --git a/storage/innobase/include/ha0ha.ic b/storage/innobase/include/ha0ha.ic
index 57f21c02324..e358b1070eb 100644
--- a/storage/innobase/include/ha0ha.ic
+++ b/storage/innobase/include/ha0ha.ic
@@ -25,8 +25,6 @@ Created 8/18/1994 Heikki Tuuri
 *************************************************************************/
 
 #ifdef BTR_CUR_HASH_ADAPT
-#include "ut0rnd.h"
-#include "mem0mem.h"
 #include "btr0types.h"
 
 /******************************************************************//**
@@ -154,45 +152,4 @@ ha_search_with_data(
 	return(NULL);
 }
 
-/***********************************************************//**
-Deletes a hash node. */
-void
-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.
-@return TRUE if found */
-UNIV_INLINE
-ibool
-ha_search_and_delete_if_found(
-/*==========================*/
-	hash_table_t*	table,	/*!< in: hash table */
-	ulint		fold,	/*!< in: folded value of the searched data */
-	const rec_t*	data)	/*!< in: pointer to the data */
-{
-	ha_node_t*	node;
-
-	ut_d(ha_btr_search_latch_x_locked(table));
-	ut_ad(btr_search_enabled);
-
-	node = ha_search_with_data(table, fold, data);
-
-	if (node) {
-		ha_delete_hash_node(table, node);
-
-		return(TRUE);
-	}
-
-	return(FALSE);
-}
 #endif /* BTR_CUR_HASH_ADAPT */
diff --git a/storage/innobase/include/hash0hash.h b/storage/innobase/include/hash0hash.h
index 29e242a540d..8d84e6e976c 100644
--- a/storage/innobase/include/hash0hash.h
+++ b/storage/innobase/include/hash0hash.h
@@ -24,11 +24,8 @@ The simple hash table utility
 Created 5/20/1997 Heikki Tuuri
 *******************************************************/
 
-#ifndef hash0hash_h
-#define hash0hash_h
-
-#include "mem0mem.h"
-#include "sync0rw.h"
+#pragma once
+#include "ut0rnd.h"
 
 struct hash_table_t;
 struct hash_cell_t{
@@ -259,26 +256,19 @@ do {\
 	}\
 } while (0)
 
-/* The hash table structure */
-struct hash_table_t {
-#ifdef BTR_CUR_HASH_ADAPT
-# if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
-	ibool			adaptive;/* TRUE if this is the hash
-					table of the adaptive hash
-					index */
-# endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
-#endif /* BTR_CUR_HASH_ADAPT */
-	ulint			n_cells;/* number of cells in the hash table */
-	hash_cell_t*		array;	/*!< pointer to cell array */
-	mem_heap_t*		heap;
-#ifdef UNIV_DEBUG
-	ulint			magic_n;
-# define HASH_TABLE_MAGIC_N	76561114
-#endif /* UNIV_DEBUG */
+/** Hash table with singly-linkde overflow lists */
+struct hash_table_t
+{
+  /** number of elements in array (a prime number) */
+  ulint n_cells;
+  /** the hash array */
+  hash_cell_t *array;
+
+  /** Create the hash table.
+  @param n  the lower bound of n_cells */
+  void create(ulint n);
 
   ulint calc_hash(ulint fold) const { return ut_hash_ulint(fold, n_cells); }
 };
 
 #include "hash0hash.ic"
-
-#endif
diff --git a/storage/innobase/include/hash0hash.ic b/storage/innobase/include/hash0hash.ic
index 63661b041fd..e6ca3b15bd0 100644
--- a/storage/innobase/include/hash0hash.ic
+++ b/storage/innobase/include/hash0hash.ic
@@ -35,7 +35,6 @@ hash_get_nth_cell(
 	ulint		n)	/*!< in: cell index */
 {
 	ut_ad(table);
-	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
 	ut_ad(n < table->n_cells);
 
 	return(table->array + n);
@@ -50,7 +49,6 @@ hash_table_clear(
 	hash_table_t*	table)	/*!< in/out: hash table */
 {
 	ut_ad(table);
-	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
 	memset(table->array, 0x0,
 	       table->n_cells * sizeof(*table->array));
 }
@@ -65,6 +63,5 @@ hash_get_n_cells(
 	hash_table_t*	table)	/*!< in: table */
 {
 	ut_ad(table);
-	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
 	return(table->n_cells);
 }
diff --git a/storage/innobase/include/ut0new.h b/storage/innobase/include/ut0new.h
index 5137c8f3ae1..87249062a83 100644
--- a/storage/innobase/include/ut0new.h
+++ b/storage/innobase/include/ut0new.h
@@ -859,7 +859,6 @@ constexpr const char* const auto_event_names[] =
   "fts0tlex",
   "gis0sea",
   "ha_innodb",
-  "ha0ha",
   "handler0alter",
   "hash0hash",
   "i_s",
diff --git a/storage/innobase/row/row0sel.cc b/storage/innobase/row/row0sel.cc
index d56985a0a2e..77a043acccc 100644
--- a/storage/innobase/row/row0sel.cc
+++ b/storage/innobase/row/row0sel.cc
@@ -3823,7 +3823,7 @@ row_sel_try_search_shortcut_for_mysql(
 	ut_ad(dict_index_is_clust(index));
 	ut_ad(!prebuilt->templ_contains_blob);
 
-	rw_lock_t* ahi_latch = btr_get_search_latch(index);
+	rw_lock_t* ahi_latch = btr_search_sys.get_latch(*index);
 	rw_lock_s_lock(ahi_latch);
 	btr_pcur_open_with_no_init(index, search_tuple, PAGE_CUR_GE,
 				   BTR_SEARCH_LEAF, pcur, ahi_latch, mtr);
diff --git a/storage/innobase/srv/srv0srv.cc b/storage/innobase/srv/srv0srv.cc
index ab0bf1164ee..84f91048068 100644
--- a/storage/innobase/srv/srv0srv.cc
+++ b/storage/innobase/srv/srv0srv.cc
@@ -965,29 +965,16 @@ srv_printf_innodb_monitor(
 	ibuf_print(file);
 
 #ifdef BTR_CUR_HASH_ADAPT
-	btr_search_x_lock_all();
 	for (ulint i = 0; i < btr_ahi_parts && btr_search_enabled; ++i) {
-		const hash_table_t* table = btr_search_sys->hash_tables[i];
-
-		ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
-		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,
-		so the data displayed may be garbage. We intentionally
-		avoid acquiring btr_search_latches[] so that the
-		diagnostic output will not stop here even in case another
-		thread hangs while holding btr_search_latches[].
-
-		This should be safe from crashes, because
-		table->heap will be pointing to the same object
-		for the full lifetime of the server. Even during
-		btr_search_disable() the heap will stay valid. */
+		const auto part= &btr_search_sys.parts[i];
+		rw_lock_s_lock(&part->latch);
+		ut_ad(part->heap->type == MEM_HEAP_FOR_BTR_SEARCH);
 		fprintf(file, "Hash table size " ULINTPF
 			", node heap has " ULINTPF " buffer(s)\n",
-			table->n_cells, heap->base.count - !heap->free_block);
+			part->table.n_cells,
+			part->heap->base.count - !part->heap->free_block);
+		rw_lock_s_unlock(&part->latch);
 	}
-	btr_search_x_unlock_all();
 
 	fprintf(file,
 		"%.2f hash searches/s, %.2f non-hash searches/s\n",
@@ -1126,22 +1113,15 @@ srv_export_innodb_status(void)
 #ifdef BTR_CUR_HASH_ADAPT
 	ulint mem_adaptive_hash = 0;
 	for (ulong i = 0; i < btr_ahi_parts; i++) {
-		rw_lock_s_lock(btr_search_latches[i]);
-		if (!btr_search_sys->hash_tables) {
-next:
-			rw_lock_s_unlock(btr_search_latches[i]);
-			continue;
-		}
-
-		hash_table_t*	ht = btr_search_sys->hash_tables[i];
+		const auto part= &btr_search_sys.parts[i];
+		rw_lock_s_lock(&part->latch);
+		if (part->heap) {
+			ut_ad(part->heap->type == MEM_HEAP_FOR_BTR_SEARCH);
 
-		ut_ad(ht);
-		ut_ad(ht->heap);
-		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);
-		goto next;
+			mem_adaptive_hash += mem_heap_get_size(part->heap)
+				+ part->table.n_cells * sizeof(hash_cell_t);
+		}
+		rw_lock_s_unlock(&part->latch);
 	}
 	export_vars.innodb_mem_adaptive_hash = mem_adaptive_hash;
 #endif
diff --git a/storage/innobase/srv/srv0start.cc b/storage/innobase/srv/srv0start.cc
index 3fe78bc1909..5dbf01c6b49 100644
--- a/storage/innobase/srv/srv0start.cc
+++ b/storage/innobase/srv/srv0start.cc
@@ -2127,9 +2127,6 @@ void innodb_shutdown()
 	      || srv_force_recovery >= SRV_FORCE_NO_TRX_UNDO);
 	ut_ad(lock_sys.is_initialised() || !srv_was_started);
 	ut_ad(log_sys.is_initialised() || !srv_was_started);
-#ifdef BTR_CUR_HASH_ADAPT
-	ut_ad(btr_search_sys || !srv_was_started);
-#endif /* BTR_CUR_HASH_ADAPT */
 	ut_ad(ibuf.index || !srv_was_started);
 
 	dict_stats_deinit();