MySQL 9.0.0
Source Code Documentation
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Redo log functions related to the log buffer. More...
Go to the source code of this file.
Classes | |
struct | Log_handle |
Handle which is used for writes to the log buffer. More... | |
Functions | |
Log - writing to the log buffer. | |
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void | log_buffer_x_lock_enter (log_t &log) |
Acquires the log buffer x-lock. More... | |
void | log_buffer_x_lock_exit (log_t &log) |
Releases the log buffer x-lock. More... | |
Log_handle | log_buffer_reserve (log_t &log, size_t len) |
Reserves space in the redo log for following write operations. More... | |
lsn_t | log_buffer_write (log_t &log, const byte *str, size_t str_len, lsn_t start_lsn) |
Writes data to the log buffer. More... | |
void | log_buffer_write_completed (log_t &log, lsn_t start_lsn, lsn_t end_lsn, bool is_last_block) |
Adds a link start_lsn -> end_lsn to the log recent written buffer. More... | |
void | log_buffer_set_first_record_group (log_t &log, lsn_t rec_group_end_lsn) |
Modifies header of log block in the log buffer, which contains a given lsn value, and sets offset to the first group of log records within the block. More... | |
Log - management of the log buffer. | |
void | log_update_buf_limit (log_t &log) |
Updates limit used when writing to log buffer. More... | |
void | log_update_buf_limit (log_t &log, lsn_t write_lsn) |
Updates limit used when writing to log buffer, according to provided write_lsn. More... | |
void | log_buffer_flush_to_disk (log_t &log, bool sync=true) |
Write to the log file up to the last log entry. More... | |
void | log_buffer_flush_to_disk (bool sync=true) |
Requests flush of the log buffer. More... | |
void | log_buffer_sync_in_background () |
Writes the log buffer to the log file. More... | |
void | log_buffer_get_last_block (log_t &log, lsn_t &last_lsn, byte *last_block, uint32_t &block_len) |
Get last redo block from redo buffer and end LSN. More... | |
bool | log_buffer_resize (log_t &log, size_t new_size) |
Changes size of the log buffer. More... | |
bool | log_buffer_resize_low (log_t &log, size_t new_size, lsn_t end_lsn) |
Changes size of the log buffer. More... | |
Log - the recent written buffer. | |
#define | log_closer_mutex_enter(log) mutex_enter(&((log).closer_mutex)) |
#define | log_closer_mutex_enter_nowait(log) mutex_enter_nowait(&((log).closer_mutex)) |
#define | log_closer_mutex_exit(log) mutex_exit(&((log).closer_mutex)) |
lsn_t | log_buffer_ready_for_write_lsn (const log_t &log) |
lsn_t | log_buffer_wait_for_ready_for_write_lsn (log_t &log, lsn_t min_lsn, uint32_t *waits_on_event=nullptr) |
Wait until log_buffer_ready_for_write_lsn() returns at least min_lsn. More... | |
void | log_advance_ready_for_write_lsn (log_t &log) |
Advances log_buffer_ready_for_write_lsn() using links in the recent written buffer. More... | |
void | log_recent_written_empty_validate (const log_t &log, lsn_t begin, lsn_t end) |
Validates that all slots in log recent written buffer for lsn values in range between begin and end, are empty. More... | |
Redo log functions related to the log buffer.
#define log_closer_mutex_enter | ( | log | ) | mutex_enter(&((log).closer_mutex)) |
#define log_closer_mutex_enter_nowait | ( | log | ) | mutex_enter_nowait(&((log).closer_mutex)) |
#define log_closer_mutex_exit | ( | log | ) | mutex_exit(&((log).closer_mutex)) |
void log_advance_ready_for_write_lsn | ( | log_t & | log | ) |
Advances log_buffer_ready_for_write_lsn() using links in the recent written buffer.
It's used by the log writer thread only.
[in] | log | redo log |
void log_buffer_flush_to_disk | ( | bool | sync = true | ) |
Requests flush of the log buffer.
[in] | sync | true: wait until the flush is done |
void log_buffer_flush_to_disk | ( | log_t & | log, |
bool | sync = true |
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) |
Write to the log file up to the last log entry.
[in,out] | log | redo log |
[in] | sync | whether we want the written log also to be flushed to disk. |
void log_buffer_get_last_block | ( | log_t & | log, |
lsn_t & | last_lsn, | ||
byte * | last_block, | ||
uint32_t & | block_len | ||
) |
Get last redo block from redo buffer and end LSN.
Note that it takes x-lock on the log buffer for a short period. Out values are always set, even when provided last_block is nullptr.
[in,out] | log | redo log |
[out] | last_lsn | end lsn of last mtr |
[out] | last_block | last redo block |
[in,out] | block_len | length in bytes |
Log_handle log_buffer_reserve | ( | log_t & | log, |
size_t | len | ||
) |
Reserves space in the redo log for following write operations.
Space is reserved for a given number of data bytes. Additionally bytes for required headers and footers of log blocks are reserved.
After the space is reserved, range of lsn values from a start_lsn to an end_lsn is assigned. The log writer thread cannot proceed further than to the start_lsn, until a link start_lsn -> end_lsn has been added to the log recent written buffer.
NOTE that the link is added after data is written to the reserved space in the log buffer. It is very critical to do all these steps as fast as possible, because very likely the log writer thread is waiting for the link.
[in,out] | log | redo log |
[in] | len | number of data bytes to reserve for write |
bool log_buffer_resize | ( | log_t & | log, |
size_t | new_size | ||
) |
Changes size of the log buffer.
This is a thread-safe version. It is used by SET GLOBAL innodb_log_buffer_size = X.
[in,out] | log | redo log |
[in] | new_size | requested new size |
Changes size of the log buffer.
This is a non-thread-safe version which might be invoked only when there are no concurrent possible writes to the log buffer. It is used in log_buffer_reserve() when a requested size to reserve is larger than size of the log buffer.
[in,out] | log | redo log |
[in] | new_size | requested new size |
[in] | end_lsn | maximum lsn written to log buffer |
Modifies header of log block in the log buffer, which contains a given lsn value, and sets offset to the first group of log records within the block.
This is used by mtr after writing a log record group which ends at lsn belonging to different log block than lsn at which the group was started. When write was finished at the last data byte of log block, it is considered ended in the next log block, because the next data byte belongs to that block.
During recovery, when recovery is started in the middle of some group of log records, it first looks for the beginning of the next group.
[in,out] | log | redo log |
[in] | rec_group_end_lsn | lsn at which the first log record group starts within the block containing this lsn value |
void log_buffer_sync_in_background | ( | ) |
Writes the log buffer to the log file.
It is intended to be called from background master thread periodically. If the log writer threads are active, this function writes nothing.
lsn_t log_buffer_wait_for_ready_for_write_lsn | ( | log_t & | log, |
lsn_t | min_lsn, | ||
uint32_t * | waits_on_event = nullptr |
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) |
Wait until log_buffer_ready_for_write_lsn() returns at least min_lsn.
[in] | log | redo log |
[in] | min_lsn | The awaited minimum value of log_buffer_ready_for_write_lsn(). |
[out] | waits_on_event | If not null, then the pointed integer will be set to the number of times this function had to wait on closer_event. |
Writes data to the log buffer.
The space in the redo log has to be reserved before calling to this function and lsn pointing to inside the reserved range of lsn values has to be provided.
The write does not have to cover the whole reserved space, but may not overflow it. If it does not cover, then returned value should be used to start the next write operation. Note that finally we must use exactly all the reserved space.
[in,out] | log | redo log |
[in] | str | memory to write data from |
[in] | str_len | number of bytes to write |
[in] | start_lsn | lsn to start writing at (the reserved space) |
Adds a link start_lsn -> end_lsn to the log recent written buffer.
This function must be called after the data has been written to the fragment of log buffer represented by range [start_lsn, end_lsn). After the link is added, the log writer may write the data to disk.
NOTE that still dirty pages for the [start_lsn, end_lsn) are not added to flush lists when this function is called.
[in,out] | log | redo log |
[in] | start_lsn | start_lsn of the link to add |
[in] | end_lsn | end_lsn of the link to add |
[in] | is_last_block | A flag to let log writer know that this [start_lsn,end_lsn) range was the last fragment of the range reserved by this thread earlier through log_buffer_reserve(..) , i.e. this thread has finished writing to the log buffer. |
void log_buffer_x_lock_enter | ( | log_t & | log | ) |
Acquires the log buffer x-lock.
[in,out] | log | redo log |
void log_buffer_x_lock_exit | ( | log_t & | log | ) |
Releases the log buffer x-lock.
[in,out] | log | redo log |
Validates that all slots in log recent written buffer for lsn values in range between begin and end, are empty.
Used during tests, crashes the program if validation does not pass.
[in] | log | redo log which buffer is validated |
[in] | begin | validation start (inclusive) |
[in] | end | validation end (exclusive) |
void log_update_buf_limit | ( | log_t & | log | ) |
Updates limit used when writing to log buffer.
Note that the log buffer may have space for log records for which we still do not have space in log files (for larger lsn values).
[in,out] | log | redo log |