Bug #31750840 ADAPTIVE HASH INDEX(AHI) BUILDING CAUSING CONTENTION ON BTR_SEARCH_LATCHES

The latches for searching in AHI were changed to non-blocking - we don't want to wait for a index which the only purpose is to speed up queries. The latches for more update operations in AHI were changed to non-blocking: - we don't have to insert new page to the index, - we don't have to try to update a reference to a failed search, we would do such operations next time we encounter them. RB#27271 Change-Id: I68e4c2ec4b7fa3beebb0cea792f084f735fcd627

Author: Marcin Babij

storage/innobase/btr/btr0sea.cc

@@ -1295,7 +1295,7 @@ static bool dict_table_can_be_evicted(
 
  See also: dict_index_remove_from_cache_low() */
 
- if (btr_search_info_get_ref_count(info, index) > 0) {
+ if (btr_search_info_get_ref_count(info) > 0) {
  return false;
  }
  }
@@ -2653,7 +2653,7 @@ static void dict_index_remove_from_cache_low(
  zero. See also: dict_table_can_be_evicted() */
 
  do {
- ulint ref_count = btr_search_info_get_ref_count(info, index);
+ ulint ref_count = btr_search_info_get_ref_count(info);
 
  if (ref_count == 0) {
  break;

storage/innobase/dict/dict0dict.cc

@@ -1394,10 +1394,10 @@ static void rtr_copy_buf(matched_rec_t *matches, const buf_block_t *block) {
  /* Skip buf_block_t::lock as it was already initialized by rtr_create_rtr_info
  */
  ut_ad(rw_lock_validate(&matches->block.lock));
- matches->block.n_hash_helps = block->n_hash_helps;
- matches->block.n_bytes = block->n_bytes;
- matches->block.n_fields = block->n_fields;
- matches->block.left_side = block->left_side;
+ matches->block.n_hash_helps.store(block->n_hash_helps.load());
+ matches->block.n_bytes.store(block->n_bytes.load());
+ matches->block.n_fields.store(block->n_fields.load());
+ matches->block.left_side.store(block->left_side.load());
  matches->block.curr_n_fields = block->curr_n_fields;
  matches->block.curr_left_side = block->curr_left_side;
  matches->block.index = block->index;

storage/innobase/gis/gis0sea.cc

@@ -257,13 +257,8 @@ bool ha_search_and_update_if_found_func(hash_table_t *table, ulint fold,
  return false;
 }
 
-/** Removes from the chain determined by fold all nodes whose data pointer
- points to the page given.
-@param[in] table Hash table
-@param[in] fold Fold value
-@param[in] page Buffer page */
-void ha_remove_all_nodes_to_page(hash_table_t *table, ulint fold,
- const page_t *page) {
+void ha_remove_a_node_to_page(hash_table_t *table, ulint fold,
+ const page_t *page) {
  ha_node_t *node;
 
  ut_ad(table);
@@ -275,30 +270,16 @@ void ha_remove_all_nodes_to_page(hash_table_t *table, ulint fold,
 
  while (node) {
  if (page_align(ha_node_get_data(node)) == page) {
- /* Remove the hash node */
+ /* Remove the hash node. It may be a node with a different fold, but we
+ don't care about it - we delete any entry in this chain for the
+ specified page. */
 
  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);
+ break;
  } 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
@@ -381,7 +362,7 @@ builds, see http://bugs.mysql.com/36941 */
 
  n_bufs = UT_LIST_GET_LEN(table->heap->base) - 1;
 
- if (table->heap->free_block) {
+ if (table->heap->free_block.load()) {
  n_bufs++;
  }
 

storage/innobase/ha/ha0ha.cc

@@ -641,81 +641,88 @@ constexpr uint32_t BTR_PATH_ARRAY_N_SLOTS = 250;
 
 /** Values for the flag documenting the used search method */
 enum btr_cur_method {
- BTR_CUR_UNSET = 0, /*!< Flag for initialization only,
- not in real use. */
- BTR_CUR_HASH = 1, /*!< successful shortcut using
- the hash index */
- BTR_CUR_HASH_FAIL, /*!< failure using hash, success using
- binary search: the misleading hash
- reference is stored in the field
- hash_node, and might be necessary to
- update */
- BTR_CUR_BINARY, /*!< success using the binary search */
- BTR_CUR_INSERT_TO_IBUF, /*!< performed the intended insert to
- the insert buffer */
- BTR_CUR_DEL_MARK_IBUF, /*!< performed the intended delete
- mark in the insert/delete buffer */
- BTR_CUR_DELETE_IBUF, /*!< performed the intended delete in
- the insert/delete buffer */
- BTR_CUR_DELETE_REF /*!< row_purge_poss_sec() failed */
+ /** Flag for initialization only, not in real use.*/
+ BTR_CUR_UNSET = 0,
+ /** successful shortcut using the hash index */
+ BTR_CUR_HASH = 1,
+ /** a search using hash index was not performed. */
+ BTR_CUR_HASH_NOT_ATTEMPTED,
+ /** failure using hash, success using binary search. The record pointing by
+ the cursor may need to be updated in AHI. */
+ BTR_CUR_HASH_FAIL,
+ /** success using the binary search */
+ BTR_CUR_BINARY,
+ /** performed the intended insert to the insert buffer */
+ BTR_CUR_INSERT_TO_IBUF,
+ /** performed the intended delete mark in the insert/delete buffer */
+ BTR_CUR_DEL_MARK_IBUF,
+ /** performed the intended delete in the insert/delete buffer */
+ BTR_CUR_DELETE_IBUF,
+ /** row_purge_poss_sec() failed */
+ BTR_CUR_DELETE_REF
 };
 
 /** The tree cursor: the definition appears here only for the compiler
 to know struct size! */
 struct btr_cur_t {
- /** index where positioned */
+ /** Index on which the cursor is positioned. */
  dict_index_t *index{nullptr};
- /** page cursor */
+ /** Page cursor. */
  page_cur_t page_cur;
- /** purge node, for BTR_DELETE */
+ /** Purge node, for BTR_DELETE */
  purge_node_t *purge_node{nullptr};
  /** this field is used to store a pointer to the left neighbor page, in the
-  cases BTR_SEARCH_PREV and BTR_MODIFY_PREV */
+ cases BTR_SEARCH_PREV and BTR_MODIFY_PREV */
  buf_block_t *left_block{nullptr};
- /*------------------------------*/
+
  /** this field is only used when btr_cur_search_to_nth_level is called for an
-  index entry insertion: the calling query thread is passed here to be used
-  in the insert buffer */
+ index entry insertion: the calling query thread is passed here to be used in
+ the insert buffer */
  que_thr_t *thr{nullptr};
- /*------------------------------*/
+
  /** The following fields are used in
- btr_cur_search_to_nth_level to pass information: */
- /** @{ */
- /** Search method used */
+ btr_cur_search_to_nth_level to pass information:
+ @{ */
+ /** Search method used. */
  btr_cur_method flag{BTR_CUR_UNSET};
  /** Tree height if the search is done for a pessimistic insert or update
-  operation */
+ operation. */
  ulint tree_height{0};
  /** If the search mode was PAGE_CUR_LE, the number of matched fields to the
- first user record to the right of the cursor record after
-  btr_cur_search_to_nth_level; for the mode PAGE_CUR_GE, the matched fields
-  to the first user record AT THE CURSOR or to the right of it; NOTE that the
-  up_match and low_match values may exceed the correct values for comparison
-  to the adjacent user record if that record is on a different leaf page!
-  (See the note in row_ins_duplicate_error_in_clust.) */
+ the first user record to the right of the cursor record after
+ btr_cur_search_to_nth_level; for the mode PAGE_CUR_GE, the matched fields to
+ the first user record AT THE CURSOR or to the right of it; NOTE that the
+ up_match and low_match values may exceed the correct values for comparison to
+ the adjacent user record if that record is on a different leaf page! See the
+ note in row_ins_duplicate_error_in_clust.  */
  ulint up_match{0};
- /** number of matched bytes to the right at the time cursor positioned; only
-  used internally in searches: not defined after the search */
+ /** Number of matched bytes to the right at the time cursor positioned; only
+ used internally in searches: not defined after the search. */
  ulint up_bytes{0};
- /** if search mode was PAGE_CUR_LE, the number of matched fields to the first
-  user record AT THE CURSOR or to the left of it after
-  btr_cur_search_to_nth_level; NOT defined for PAGE_CUR_GE or any other
-  search modes; see also the NOTE in up_match! */
+ /** If search mode was PAGE_CUR_LE, the number of matched fields to the first
+ user record AT THE CURSOR or to the left of it after
+ btr_cur_search_to_nth_level; NOT defined for PAGE_CUR_GE or any other search
+ modes; see also the NOTE in up_match! */
  ulint low_match{0};
- /** number of matched bytes to the left at the time cursor positioned; only
-  used internally in searches: not defined after the search */
+ /** Number of matched bytes to the left at the time cursor positioned; only
+ used internally in searches: not defined after the search. */
  ulint low_bytes{0};
- /** prefix length used in a hash search if hash_node != NULL */
+ /** Prefix length used in a hash search if flag is any of BTR_CUR_HASH,
+ BTR_CUR_HASH_FAIL or BTR_CUR_HASH_NOT_ATTEMPTED. */
  ulint n_fields{0};
- /** hash prefix bytes if hash_node != NULL */
+ /** Hash prefix bytes if flag is any of BTR_CUR_HASH, BTR_CUR_HASH_FAIL or
+ BTR_CUR_HASH_NOT_ATTEMPTED. */
  ulint n_bytes{0};
- /** fold value used in the search if flag is BTR_CUR_HASH */
+ /** fold value used in the search if flag is any of BTR_CUR_HASH,
+ BTR_CUR_HASH_FAIL or BTR_CUR_HASH_NOT_ATTEMPTED. */
  ulint fold{0};
  /** @} */
- /** in estimating the number of rows in range, we store in this array
- information of the path through the tree */
+
+ /** In estimating the number of rows in range, we store in this array
+ information of the path through the tree. */
  btr_path_t *path_arr{nullptr};
- /** rtree search info */
+
+ /** rtree search info. */
  rtr_info_t *rtr_info{nullptr};
 
  /** Ownership of the above rtr_info member. */