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MySQL
8.0.19
Source Code Documentation
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MySQL
8.0.19
Source Code Documentation
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#include <buf0buf.h>
Public Attributes | |
General fields | |
None of these bit-fields must be modified without holding buf_page_get_mutex() [buf_block_t::mutex or buf_pool->zip_mutex], since they can be stored in the same machine word.
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| page_id_t | id |
| Page id. More... | |
| page_size_t | size |
| Page size. More... | |
| uint32_t | buf_fix_count |
| Count of how manyfold this block is currently bufferfixed. More... | |
| buf_io_fix | io_fix |
| type of pending I/O operation. More... | |
| buf_page_state | state |
| Block state. More... | |
| unsigned | flush_type: 2 |
| if this block is currently being flushed to disk, this tells the flush_type. More... | |
| unsigned | buf_pool_index: 6 |
| index number of the buffer pool that this block belongs to More... | |
| page_zip_des_t | zip |
| compressed page; zip.data (but not the data it points to) is protected by buf_pool->zip_mutex; state == BUF_BLOCK_ZIP_PAGE and zip.data == NULL means an active buf_pool->watch More... | |
| buf_page_t * | hash |
| node used in chaining to buf_pool->page_hash or buf_pool->zip_hash More... | |
| ibool | in_page_hash |
| TRUE if in buf_pool->page_hash. More... | |
| ibool | in_zip_hash |
| TRUE if in buf_pool->zip_hash. More... | |
Page flushing fields | |
| ibool | in_flush_list |
| TRUE if in buf_pool->flush_list; when buf_pool->flush_list_mutex is free, the following should hold: in_flush_list == (state == BUF_BLOCK_FILE_PAGE || state == BUF_BLOCK_ZIP_DIRTY) Writes to this field must be covered by both block->mutex and buf_pool->flush_list_mutex. More... | |
| ibool | in_free_list |
| TRUE if in buf_pool->free; when buf_pool->free_list_mutex is free, the following should hold: in_free_list == (state == BUF_BLOCK_NOT_USED) More... | |
| FlushObserver * | flush_observer |
| flush observer More... | |
| lsn_t | newest_modification |
| log sequence number of the youngest modification to this block, zero if not modified. More... | |
| lsn_t | oldest_modification |
| log sequence number of the START of the log entry written of the oldest modification to this block which has not yet been flushed on disk; zero if all modifications are on disk. More... | |
| UT_LIST_NODE_T (buf_page_t) list | |
| based on state, this is a list node, protected by the corresponding list mutex, in one of the following lists in buf_pool: More... | |
LRU replacement algorithm fields | |
These fields are protected by both buf_pool->LRU_list_mutex and the block mutex. | |
| ibool | in_LRU_list |
| TRUE if the page is in the LRU list; used in debugging. More... | |
| unsigned | old: 1 |
| TRUE if the block is in the old blocks in buf_pool->LRU_old. More... | |
| unsigned | freed_page_clock: 31 |
| the value of buf_pool->freed_page_clock when this block was the last time put to the head of the LRU list; a thread is allowed to read this for heuristic purposes without holding any mutex or latch More... | |
| unsigned | access_time |
| time of first access, or 0 if the block was never accessed in the buffer pool. More... | |
| ibool | file_page_was_freed |
| this is set to TRUE when fsp frees a page in buffer pool; protected by buf_pool->zip_mutex or buf_block_t::mutex. More... | |
| UT_LIST_NODE_T (buf_page_t) LRU | |
| node of the LRU list More... | |
| buf_page_t::UT_LIST_NODE_T | ( | buf_page_t | ) |
based on state, this is a list node, protected by the corresponding list mutex, in one of the following lists in buf_pool:
The node pointers are protected by the corresponding list mutex.
The contents of the list node is undefined if !in_flush_list && state == BUF_BLOCK_FILE_PAGE, or if state is one of BUF_BLOCK_MEMORY, BUF_BLOCK_REMOVE_HASH or BUF_BLOCK_READY_IN_USE.
| buf_page_t::UT_LIST_NODE_T | ( | buf_page_t | ) |
node of the LRU list
| unsigned buf_page_t::access_time |
time of first access, or 0 if the block was never accessed in the buffer pool.
Protected by block mutex
| uint32_t buf_page_t::buf_fix_count |
Count of how manyfold this block is currently bufferfixed.
| unsigned buf_page_t::buf_pool_index |
index number of the buffer pool that this block belongs to
| ibool buf_page_t::file_page_was_freed |
this is set to TRUE when fsp frees a page in buffer pool; protected by buf_pool->zip_mutex or buf_block_t::mutex.
| FlushObserver* buf_page_t::flush_observer |
flush observer
| unsigned buf_page_t::flush_type |
if this block is currently being flushed to disk, this tells the flush_type.
| unsigned buf_page_t::freed_page_clock |
the value of buf_pool->freed_page_clock when this block was the last time put to the head of the LRU list; a thread is allowed to read this for heuristic purposes without holding any mutex or latch
| buf_page_t* buf_page_t::hash |
node used in chaining to buf_pool->page_hash or buf_pool->zip_hash
| page_id_t buf_page_t::id |
Page id.
| ibool buf_page_t::in_flush_list |
TRUE if in buf_pool->flush_list; when buf_pool->flush_list_mutex is free, the following should hold: in_flush_list == (state == BUF_BLOCK_FILE_PAGE || state == BUF_BLOCK_ZIP_DIRTY) Writes to this field must be covered by both block->mutex and buf_pool->flush_list_mutex.
Hence reads can happen while holding any one of the two mutexes
| ibool buf_page_t::in_free_list |
TRUE if in buf_pool->free; when buf_pool->free_list_mutex is free, the following should hold: in_free_list == (state == BUF_BLOCK_NOT_USED)
| ibool buf_page_t::in_LRU_list |
TRUE if the page is in the LRU list; used in debugging.
| ibool buf_page_t::in_page_hash |
TRUE if in buf_pool->page_hash.
| ibool buf_page_t::in_zip_hash |
TRUE if in buf_pool->zip_hash.
| buf_io_fix buf_page_t::io_fix |
type of pending I/O operation.
| lsn_t buf_page_t::newest_modification |
log sequence number of the youngest modification to this block, zero if not modified.
Protected by block mutex
| unsigned buf_page_t::old |
TRUE if the block is in the old blocks in buf_pool->LRU_old.
| lsn_t buf_page_t::oldest_modification |
log sequence number of the START of the log entry written of the oldest modification to this block which has not yet been flushed on disk; zero if all modifications are on disk.
Writes to this field must be covered by both block->mutex and buf_pool->flush_list_mutex. Hence reads can happen while holding any one of the two mutexes
| page_size_t buf_page_t::size |
Page size.
| buf_page_state buf_page_t::state |
Block state.
| page_zip_des_t buf_page_t::zip |
compressed page; zip.data (but not the data it points to) is protected by buf_pool->zip_mutex; state == BUF_BLOCK_ZIP_PAGE and zip.data == NULL means an active buf_pool->watch
1.8.18