MySQL 8.0.40
Source Code Documentation
|
#include <btr0sea.h>
Public Member Functions | |
void | initialize (size_t hash_size) |
Public Attributes | |
rw_lock_t | latch |
The latch protecting the adaptive search part: this latch protects the (1) positions of records on those pages where a hash index has been built. More... | |
hash_table_t * | hash_table |
The adaptive hash table, mapping dtuple_hash values to rec_t pointers on index pages. More... | |
std::atomic< buf_block_t * > | free_block_for_heap |
A pointer to a free block that the heap in the hash table may use for adding new hash nodes. More... | |
void btr_search_sys_t::search_part_t::initialize | ( | size_t | hash_size | ) |
std::atomic<buf_block_t *> btr_search_sys_t::search_part_t::free_block_for_heap |
A pointer to a free block that the heap in the hash table may use for adding new hash nodes.
Changes to nullptr are done under appropriate X-latched rwlock. Changes from nullptr to non-nullptr are done without any protection. Changes from non-null to a different non-null are prohibited.
hash_table_t* btr_search_sys_t::search_part_t::hash_table |
The adaptive hash table, mapping dtuple_hash values to rec_t pointers on index pages.
For any hash value at most one pointer is hold. Is protected by the part's latch. It is in a separate cache line to not collide with the possible multiple readers that are registering for the latching.
rw_lock_t btr_search_sys_t::search_part_t::latch |
The latch protecting the adaptive search part: this latch 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.