/***************************************************************************** Copyright (c) 1995, 2010, Oracle and/or its affiliates. All Rights Reserved. Copyright (c) 2009, Google Inc. Portions of this file contain modifications contributed and copyrighted by Google, Inc. Those modifications are gratefully acknowledged and are described briefly in the InnoDB documentation. The contributions by Google are incorporated with their permission, and subject to the conditions contained in the file COPYING.Google. 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, Suite 500, Boston, MA 02110-1335 USA *****************************************************************************/ /**************************************************//** @file include/log0log.h Database log Created 12/9/1995 Heikki Tuuri *******************************************************/ #ifndef log0log_h #define log0log_h #include "univ.i" #include "ut0byte.h" #include "ut0lst.h" #ifndef UNIV_HOTBACKUP #include "sync0sync.h" #include "sync0rw.h" #endif /* !UNIV_HOTBACKUP */ /* Type used for all log sequence number storage and arithmetics */ typedef ib_uint64_t lsn_t; /** Redo log buffer */ typedef struct log_struct log_t; /** Redo log group */ typedef struct log_group_struct log_group_t; #ifdef UNIV_DEBUG /** Flag: write to log file? */ extern ibool log_do_write; /** Flag: enable debug output when writing to the log? */ extern ibool log_debug_writes; #else /* UNIV_DEBUG */ /** Write to log */ # define log_do_write TRUE #endif /* UNIV_DEBUG */ /** Wait modes for log_write_up_to @{ */ #define LOG_NO_WAIT 91 #define LOG_WAIT_ONE_GROUP 92 #define LOG_WAIT_ALL_GROUPS 93 /* @} */ /** Maximum number of log groups in log_group_struct::checkpoint_buf */ #define LOG_MAX_N_GROUPS 32 #ifndef UNIV_HOTBACKUP /****************************************************************//** Sets the global variable log_fsp_current_free_limit. Also makes a checkpoint, so that we know that the limit has been written to a log checkpoint field on disk. */ UNIV_INTERN void log_fsp_current_free_limit_set_and_checkpoint( /*==========================================*/ ulint limit); /*!< in: limit to set */ #endif /* !UNIV_HOTBACKUP */ /*******************************************************************//** Calculates where in log files we find a specified lsn. @return log file number */ UNIV_INTERN ulint log_calc_where_lsn_is( /*==================*/ ib_int64_t* log_file_offset, /*!< out: offset in that file (including the header) */ ib_uint64_t first_header_lsn, /*!< in: first log file start lsn */ ib_uint64_t lsn, /*!< in: lsn whose position to determine */ ulint n_log_files, /*!< in: total number of log files */ ib_int64_t log_file_size); /*!< in: log file size (including the header) */ #ifndef UNIV_HOTBACKUP /************************************************************//** Writes to the log the string given. The log must be released with log_release. @return end lsn of the log record, zero if did not succeed */ UNIV_INLINE ib_uint64_t log_reserve_and_write_fast( /*=======================*/ const void* str, /*!< in: string */ ulint len, /*!< in: string length */ ib_uint64_t* start_lsn);/*!< out: start lsn of the log record */ /***********************************************************************//** Releases the log mutex. */ UNIV_INLINE void log_release(void); /*=============*/ /***********************************************************************//** Checks if there is need for a log buffer flush or a new checkpoint, and does this if yes. Any database operation should call this when it has modified more than about 4 pages. NOTE that this function may only be called when the OS thread owns no synchronization objects except the dictionary mutex. */ UNIV_INLINE void log_free_check(void); /*================*/ /************************************************************//** Opens the log for log_write_low. The log must be closed with log_close and released with log_release. @return start lsn of the log record */ UNIV_INTERN ib_uint64_t log_reserve_and_open( /*=================*/ ulint len); /*!< in: length of data to be catenated */ /************************************************************//** Writes to the log the string given. It is assumed that the caller holds the log mutex. */ UNIV_INTERN void log_write_low( /*==========*/ byte* str, /*!< in: string */ ulint str_len); /*!< in: string length */ /************************************************************//** Closes the log. @return lsn */ UNIV_INTERN ib_uint64_t log_close(void); /*===========*/ /************************************************************//** Gets the current lsn. @return current lsn */ UNIV_INLINE ib_uint64_t log_get_lsn(void); /*=============*/ /************************************************************//** Gets the last lsn that is fully flushed to disk. @return last flushed lsn */ UNIV_INLINE ib_uint64_t log_get_flush_lsn(void); /*=============*/ /**************************************************************** Gets the log group capacity. It is OK to read the value without holding log_sys->mutex because it is constant. @return log group capacity */ UNIV_INLINE ulint log_get_capacity(void); /*==================*/ /******************************************************//** Initializes the log. */ UNIV_INTERN void log_init(void); /*==========*/ /******************************************************************//** Inits a log group to the log system. */ UNIV_INTERN void log_group_init( /*===========*/ ulint id, /*!< in: group id */ ulint n_files, /*!< in: number of log files */ ulint file_size, /*!< in: log file size in bytes */ ulint space_id, /*!< in: space id of the file space which contains the log files of this group */ ulint archive_space_id); /*!< in: space id of the file space which contains some archived log files for this group; currently, only for the first log group this is used */ /******************************************************//** Completes an i/o to a log file. */ UNIV_INTERN void log_io_complete( /*============*/ log_group_t* group); /*!< in: log group */ /******************************************************//** This function is called, e.g., when a transaction wants to commit. It checks that the log has been written to the log file up to the last log entry written by the transaction. If there is a flush running, it waits and checks if the flush flushed enough. If not, starts a new flush. */ UNIV_INTERN void log_write_up_to( /*============*/ ib_uint64_t lsn, /*!< in: log sequence number up to which the log should be written, IB_ULONGLONG_MAX if not specified */ ulint wait, /*!< in: LOG_NO_WAIT, LOG_WAIT_ONE_GROUP, or LOG_WAIT_ALL_GROUPS */ ibool flush_to_disk); /*!< in: TRUE if we want the written log also to be flushed to disk */ /****************************************************************//** Does a syncronous flush of the log buffer to disk. */ UNIV_INTERN void log_buffer_flush_to_disk(void); /*==========================*/ /****************************************************************//** This functions writes the log buffer to the log file and if 'flush' is set it forces a flush of the log file as well. This is meant to be called from background master thread only as it does not wait for the write (+ possible flush) to finish. */ UNIV_INTERN void log_buffer_sync_in_background( /*==========================*/ ibool flush); /*checkpoint_buf. */ UNIV_INTERN void log_group_read_checkpoint_info( /*===========================*/ log_group_t* group, /*!< in: log group */ ulint field); /*!< in: LOG_CHECKPOINT_1 or LOG_CHECKPOINT_2 */ /*******************************************************************//** Gets info from a checkpoint about a log group. */ UNIV_INTERN void log_checkpoint_get_nth_group_info( /*==============================*/ const byte* buf, /*!< in: buffer containing checkpoint info */ ulint n, /*!< in: nth slot */ ulint* file_no,/*!< out: archived file number */ ulint* offset);/*!< out: archived file offset */ /******************************************************//** Writes checkpoint info to groups. */ UNIV_INTERN void log_groups_write_checkpoint_info(void); /*==================================*/ /********************************************************************//** Starts an archiving operation. @return TRUE if succeed, FALSE if an archiving operation was already running */ UNIV_INTERN ibool log_archive_do( /*===========*/ ibool sync, /*!< in: TRUE if synchronous operation is desired */ ulint* n_bytes);/*!< out: archive log buffer size, 0 if nothing to archive */ /****************************************************************//** Writes the log contents to the archive up to the lsn when this function was called, and stops the archiving. When archiving is started again, the archived log file numbers start from a number one higher, so that the archiving will not write again to the archived log files which exist when this function returns. @return DB_SUCCESS or DB_ERROR */ UNIV_INTERN ulint log_archive_stop(void); /*==================*/ /****************************************************************//** Starts again archiving which has been stopped. @return DB_SUCCESS or DB_ERROR */ UNIV_INTERN ulint log_archive_start(void); /*===================*/ /****************************************************************//** Stop archiving the log so that a gap may occur in the archived log files. @return DB_SUCCESS or DB_ERROR */ UNIV_INTERN ulint log_archive_noarchivelog(void); /*==========================*/ /****************************************************************//** Start archiving the log so that a gap may occur in the archived log files. @return DB_SUCCESS or DB_ERROR */ UNIV_INTERN ulint log_archive_archivelog(void); /*========================*/ /******************************************************//** Generates an archived log file name. */ UNIV_INTERN void log_archived_file_name_gen( /*=======================*/ char* buf, /*!< in: buffer where to write */ ulint id, /*!< in: group id */ ulint file_no);/*!< in: file number */ #else /* !UNIV_HOTBACKUP */ /******************************************************//** Writes info to a buffer of a log group when log files are created in backup restoration. */ UNIV_INTERN void log_reset_first_header_and_checkpoint( /*==================================*/ byte* hdr_buf,/*!< in: buffer which will be written to the start of the first log file */ ib_uint64_t start); /*!< in: lsn of the start of the first log file; we pretend that there is a checkpoint at start + LOG_BLOCK_HDR_SIZE */ #endif /* !UNIV_HOTBACKUP */ /********************************************************************//** Checks that there is enough free space in the log to start a new query step. Flushes the log buffer or makes a new checkpoint if necessary. NOTE: this function may only be called if the calling thread owns no synchronization objects! */ UNIV_INTERN void log_check_margins(void); /*===================*/ #ifndef UNIV_HOTBACKUP /******************************************************//** Reads a specified log segment to a buffer. */ UNIV_INTERN void log_group_read_log_seg( /*===================*/ ulint type, /*!< in: LOG_ARCHIVE or LOG_RECOVER */ byte* buf, /*!< in: buffer where to read */ log_group_t* group, /*!< in: log group */ ib_uint64_t start_lsn, /*!< in: read area start */ ib_uint64_t end_lsn); /*!< in: read area end */ /******************************************************//** Writes a buffer to a log file group. */ UNIV_INTERN void log_group_write_buf( /*================*/ log_group_t* group, /*!< in: log group */ byte* buf, /*!< in: buffer */ ulint len, /*!< in: buffer len; must be divisible by OS_FILE_LOG_BLOCK_SIZE */ ib_uint64_t start_lsn, /*!< in: start lsn of the buffer; must be divisible by OS_FILE_LOG_BLOCK_SIZE */ ulint new_data_offset);/*!< in: start offset of new data in buf: this parameter is used to decide if we have to write a new log file header */ /********************************************************//** Sets the field values in group to correspond to a given lsn. For this function to work, the values must already be correctly initialized to correspond to some lsn, for instance, a checkpoint lsn. */ UNIV_INTERN void log_group_set_fields( /*=================*/ log_group_t* group, /*!< in/out: group */ ib_uint64_t lsn); /*!< in: lsn for which the values should be set */ /******************************************************//** Calculates the data capacity of a log group, when the log file headers are not included. @return capacity in bytes */ UNIV_INTERN ulint log_group_get_capacity( /*===================*/ const log_group_t* group); /*!< in: log group */ #endif /* !UNIV_HOTBACKUP */ /************************************************************//** Gets a log block flush bit. @return TRUE if this block was the first to be written in a log flush */ UNIV_INLINE ibool log_block_get_flush_bit( /*====================*/ const byte* log_block); /*!< in: log block */ /************************************************************//** Gets a log block number stored in the header. @return log block number stored in the block header */ UNIV_INLINE ulint log_block_get_hdr_no( /*=================*/ const byte* log_block); /*!< in: log block */ /************************************************************//** Gets a log block data length. @return log block data length measured as a byte offset from the block start */ UNIV_INLINE ulint log_block_get_data_len( /*===================*/ const byte* log_block); /*!< in: log block */ /************************************************************//** Sets the log block data length. */ UNIV_INLINE void log_block_set_data_len( /*===================*/ byte* log_block, /*!< in/out: log block */ ulint len); /*!< in: data length */ /************************************************************//** Calculates the checksum for a log block. @return checksum */ UNIV_INLINE ulint log_block_calc_checksum( /*====================*/ const byte* block); /*!< in: log block */ /************************************************************//** Gets a log block checksum field value. @return checksum */ UNIV_INLINE ulint log_block_get_checksum( /*===================*/ const byte* log_block); /*!< in: log block */ /************************************************************//** Sets a log block checksum field value. */ UNIV_INLINE void log_block_set_checksum( /*===================*/ byte* log_block, /*!< in/out: log block */ ulint checksum); /*!< in: checksum */ /************************************************************//** Gets a log block first mtr log record group offset. @return first mtr log record group byte offset from the block start, 0 if none */ UNIV_INLINE ulint log_block_get_first_rec_group( /*==========================*/ const byte* log_block); /*!< in: log block */ /************************************************************//** Sets the log block first mtr log record group offset. */ UNIV_INLINE void log_block_set_first_rec_group( /*==========================*/ byte* log_block, /*!< in/out: log block */ ulint offset); /*!< in: offset, 0 if none */ /************************************************************//** Gets a log block checkpoint number field (4 lowest bytes). @return checkpoint no (4 lowest bytes) */ UNIV_INLINE ulint log_block_get_checkpoint_no( /*========================*/ const byte* log_block); /*!< in: log block */ /************************************************************//** Initializes a log block in the log buffer. */ UNIV_INLINE void log_block_init( /*===========*/ byte* log_block, /*!< in: pointer to the log buffer */ ib_uint64_t lsn); /*!< in: lsn within the log block */ /************************************************************//** Initializes a log block in the log buffer in the old, < 3.23.52 format, where there was no checksum yet. */ UNIV_INLINE void log_block_init_in_old_format( /*=========================*/ byte* log_block, /*!< in: pointer to the log buffer */ ib_uint64_t lsn); /*!< in: lsn within the log block */ /************************************************************//** Converts a lsn to a log block number. @return log block number, it is > 0 and <= 1G */ UNIV_INLINE ulint log_block_convert_lsn_to_no( /*========================*/ ib_uint64_t lsn); /*!< in: lsn of a byte within the block */ /******************************************************//** Prints info of the log. */ UNIV_INTERN void log_print( /*======*/ FILE* file); /*!< in: file where to print */ /******************************************************//** Peeks the current lsn. @return TRUE if success, FALSE if could not get the log system mutex */ UNIV_INTERN ibool log_peek_lsn( /*=========*/ ib_uint64_t* lsn); /*!< out: if returns TRUE, current lsn is here */ /**********************************************************************//** Refreshes the statistics used to print per-second averages. */ UNIV_INTERN void log_refresh_stats(void); /*===================*/ /********************************************************** Shutdown the log system but do not release all the memory. */ UNIV_INTERN void log_shutdown(void); /*==============*/ /********************************************************** Free the log system data structures. */ UNIV_INTERN void log_mem_free(void); /*==============*/ extern log_t* log_sys; /* Values used as flags */ #define LOG_FLUSH 7652559 #define LOG_CHECKPOINT 78656949 #ifdef UNIV_LOG_ARCHIVE # define LOG_ARCHIVE 11122331 #endif /* UNIV_LOG_ARCHIVE */ #define LOG_RECOVER 98887331 /* The counting of lsn's starts from this value: this must be non-zero */ #define LOG_START_LSN ((ib_uint64_t) (16 * OS_FILE_LOG_BLOCK_SIZE)) #define LOG_BUFFER_SIZE (srv_log_buffer_size * UNIV_PAGE_SIZE) #define LOG_ARCHIVE_BUF_SIZE (srv_log_buffer_size * UNIV_PAGE_SIZE / 4) /* Offsets of a log block header */ #define LOG_BLOCK_HDR_NO 0 /* block number which must be > 0 and is allowed to wrap around at 2G; the highest bit is set to 1 if this is the first log block in a log flush write segment */ #define LOG_BLOCK_FLUSH_BIT_MASK 0x80000000UL /* mask used to get the highest bit in the preceding field */ #define LOG_BLOCK_HDR_DATA_LEN 4 /* number of bytes of log written to this block */ #define LOG_BLOCK_FIRST_REC_GROUP 6 /* offset of the first start of an mtr log record group in this log block, 0 if none; if the value is the same as LOG_BLOCK_HDR_DATA_LEN, it means that the first rec group has not yet been catenated to this log block, but if it will, it will start at this offset; an archive recovery can start parsing the log records starting from this offset in this log block, if value not 0 */ #define LOG_BLOCK_CHECKPOINT_NO 8 /* 4 lower bytes of the value of log_sys->next_checkpoint_no when the log block was last written to: if the block has not yet been written full, this value is only updated before a log buffer flush */ #define LOG_BLOCK_HDR_SIZE 12 /* size of the log block header in bytes */ /* Offsets of a log block trailer from the end of the block */ #define LOG_BLOCK_CHECKSUM 4 /* 4 byte checksum of the log block contents; in InnoDB versions < 3.23.52 this did not contain the checksum but the same value as .._HDR_NO */ #define LOG_BLOCK_TRL_SIZE 4 /* trailer size in bytes */ /* Offsets for a checkpoint field */ #define LOG_CHECKPOINT_NO 0 #define LOG_CHECKPOINT_LSN 8 #define LOG_CHECKPOINT_OFFSET 16 #define LOG_CHECKPOINT_LOG_BUF_SIZE 20 #define LOG_CHECKPOINT_ARCHIVED_LSN 24 #define LOG_CHECKPOINT_GROUP_ARRAY 32 /* For each value smaller than LOG_MAX_N_GROUPS the following 8 bytes: */ #define LOG_CHECKPOINT_ARCHIVED_FILE_NO 0 #define LOG_CHECKPOINT_ARCHIVED_OFFSET 4 #define LOG_CHECKPOINT_ARRAY_END (LOG_CHECKPOINT_GROUP_ARRAY\ + LOG_MAX_N_GROUPS * 8) #define LOG_CHECKPOINT_CHECKSUM_1 LOG_CHECKPOINT_ARRAY_END #define LOG_CHECKPOINT_CHECKSUM_2 (4 + LOG_CHECKPOINT_ARRAY_END) #define LOG_CHECKPOINT_FSP_FREE_LIMIT (8 + LOG_CHECKPOINT_ARRAY_END) /* current fsp free limit in tablespace 0, in units of one megabyte; this information is only used by ibbackup to decide if it can truncate unused ends of non-auto-extending data files in space 0 */ #define LOG_CHECKPOINT_FSP_MAGIC_N (12 + LOG_CHECKPOINT_ARRAY_END) /* this magic number tells if the checkpoint contains the above field: the field was added to InnoDB-3.23.50 */ #define LOG_CHECKPOINT_SIZE (16 + LOG_CHECKPOINT_ARRAY_END) #define LOG_CHECKPOINT_FSP_MAGIC_N_VAL 1441231243 /* Offsets of a log file header */ #define LOG_GROUP_ID 0 /* log group number */ #define LOG_FILE_START_LSN 4 /* lsn of the start of data in this log file */ #define LOG_FILE_NO 12 /* 4-byte archived log file number; this field is only defined in an archived log file */ #define LOG_FILE_WAS_CREATED_BY_HOT_BACKUP 16 /* a 32-byte field which contains the string 'ibbackup' and the creation time if the log file was created by ibbackup --restore; when mysqld is first time started on the restored database, it can print helpful info for the user */ #define LOG_FILE_OS_FILE_LOG_BLOCK_SIZE 64 /* extend to record log_block_size of XtraDB. 0 means default 512 */ #define LOG_FILE_ARCH_COMPLETED OS_FILE_LOG_BLOCK_SIZE /* this 4-byte field is TRUE when the writing of an archived log file has been completed; this field is only defined in an archived log file */ #define LOG_FILE_END_LSN (OS_FILE_LOG_BLOCK_SIZE + 4) /* lsn where the archived log file at least extends: actually the archived log file may extend to a later lsn, as long as it is within the same log block as this lsn; this field is defined only when an archived log file has been completely written */ #define LOG_CHECKPOINT_1 OS_FILE_LOG_BLOCK_SIZE /* first checkpoint field in the log header; we write alternately to the checkpoint fields when we make new checkpoints; this field is only defined in the first log file of a log group */ #define LOG_CHECKPOINT_2 (3 * OS_FILE_LOG_BLOCK_SIZE) /* second checkpoint field in the log header */ #define LOG_FILE_HDR_SIZE (4 * OS_FILE_LOG_BLOCK_SIZE) #define LOG_GROUP_OK 301 #define LOG_GROUP_CORRUPTED 302 /** Log group consists of a number of log files, each of the same size; a log group is implemented as a space in the sense of the module fil0fil. */ struct log_group_struct{ /* The following fields are protected by log_sys->mutex */ ulint id; /*!< log group id */ ulint n_files; /*!< number of files in the group */ ulint file_size; /*!< individual log file size in bytes, including the log file header */ ulint space_id; /*!< file space which implements the log group */ ulint state; /*!< LOG_GROUP_OK or LOG_GROUP_CORRUPTED */ ib_uint64_t lsn; /*!< lsn used to fix coordinates within the log group */ ulint lsn_offset; /*!< the offset of the above lsn */ ulint n_pending_writes;/*!< number of currently pending flush writes for this log group */ byte** file_header_bufs_ptr;/*!< unaligned buffers */ byte** file_header_bufs;/*!< buffers for each file header in the group */ #ifdef UNIV_LOG_ARCHIVE /*-----------------------------*/ byte** archive_file_header_bufs_ptr;/*!< unaligned buffers */ byte** archive_file_header_bufs;/*!< buffers for each file header in the group */ ulint archive_space_id;/*!< file space which implements the log group archive */ ulint archived_file_no;/*!< file number corresponding to log_sys->archived_lsn */ ulint archived_offset;/*!< file offset corresponding to log_sys->archived_lsn, 0 if we have not yet written to the archive file number archived_file_no */ ulint next_archived_file_no;/*!< during an archive write, until the write is completed, we store the next value for archived_file_no here: the write completion function then sets the new value to ..._file_no */ ulint next_archived_offset; /*!< like the preceding field */ #endif /* UNIV_LOG_ARCHIVE */ /*-----------------------------*/ ib_uint64_t scanned_lsn; /*!< used only in recovery: recovery scan succeeded up to this lsn in this log group */ byte* checkpoint_buf_ptr;/*!< unaligned checkpoint header */ byte* checkpoint_buf; /*!< checkpoint header is written from this buffer to the group */ UT_LIST_NODE_T(log_group_t) log_groups; /*!< list of log groups */ }; /** Redo log buffer */ struct log_struct{ byte pad[64]; /*!< padding to prevent other memory update hotspots from residing on the same memory cache line */ ib_uint64_t lsn; /*!< log sequence number */ ulint buf_free; /*!< first free offset within the log buffer */ #ifndef UNIV_HOTBACKUP mutex_t mutex; /*!< mutex protecting the log */ mutex_t log_flush_order_mutex;/*!< mutex to serialize access to the flush list when we are putting dirty blocks in the list. The idea behind this mutex is to be able to release log_sys->mutex during mtr_commit and still ensure that insertions in the flush_list happen in the LSN order. */ #endif /* !UNIV_HOTBACKUP */ byte* buf_ptr; /* unaligned log buffer */ byte* buf; /*!< log buffer */ ulint buf_size; /*!< log buffer size in bytes */ ulint max_buf_free; /*!< recommended maximum value of buf_free, after which the buffer is flushed */ ulint old_buf_free; /*!< value of buf free when log was last time opened; only in the debug version */ ib_uint64_t old_lsn; /*!< value of lsn when log was last time opened; only in the debug version */ ibool check_flush_or_checkpoint; /*!< this is set to TRUE when there may be need to flush the log buffer, or preflush buffer pool pages, or make a checkpoint; this MUST be TRUE when lsn - last_checkpoint_lsn > max_checkpoint_age; this flag is peeked at by log_free_check(), which does not reserve the log mutex */ UT_LIST_BASE_NODE_T(log_group_t) log_groups; /*!< log groups */ #ifndef UNIV_HOTBACKUP /** The fields involved in the log buffer flush @{ */ ulint buf_next_to_write;/*!< first offset in the log buffer where the byte content may not exist written to file, e.g., the start offset of a log record catenated later; this is advanced when a flush operation is completed to all the log groups */ ib_uint64_t written_to_some_lsn; /*!< first log sequence number not yet written to any log group; for this to be advanced, it is enough that the write i/o has been completed for any one log group */ ib_uint64_t written_to_all_lsn; /*!< first log sequence number not yet written to some log group; for this to be advanced, it is enough that the write i/o has been completed for all log groups. Note that since InnoDB currently has only one log group therefore this value is redundant. Also it is possible that this value falls behind the flushed_to_disk_lsn transiently. It is appropriate to use either flushed_to_disk_lsn or write_lsn which are always up-to-date and accurate. */ ib_uint64_t write_lsn; /*!< end lsn for the current running write */ ulint write_end_offset;/*!< the data in buffer has been written up to this offset when the current write ends: this field will then be copied to buf_next_to_write */ ib_uint64_t current_flush_lsn;/*!< end lsn for the current running write + flush operation */ ib_uint64_t flushed_to_disk_lsn; /*!< how far we have written the log AND flushed to disk */ ulint n_pending_writes;/*!< number of currently pending flushes or writes */ /* NOTE on the 'flush' in names of the fields below: starting from 4.0.14, we separate the write of the log file and the actual fsync() or other method to flush it to disk. The names below shhould really be 'flush_or_write'! */ os_event_t no_flush_event; /*!< this event is in the reset state when a flush or a write is running; a thread should wait for this without owning the log mutex, but NOTE that to set or reset this event, the thread MUST own the log mutex! */ ibool one_flushed; /*!< during a flush, this is first FALSE and becomes TRUE when one log group has been written or flushed */ os_event_t one_flushed_event;/*!< this event is reset when the flush or write has not yet completed for any log group; e.g., this means that a transaction has been committed when this is set; a thread should wait for this without owning the log mutex, but NOTE that to set or reset this event, the thread MUST own the log mutex! */ ulint n_log_ios; /*!< number of log i/os initiated thus far */ ulint n_log_ios_old; /*!< number of log i/o's at the previous printout */ time_t last_printout_time;/*!< when log_print was last time called */ /* @} */ /** Fields involved in checkpoints @{ */ ulint log_group_capacity; /*!< capacity of the log group; if the checkpoint age exceeds this, it is a serious error because it is possible we will then overwrite log and spoil crash recovery */ ulint max_modified_age_async; /*!< when this recommended value for lsn - buf_pool_get_oldest_modification() is exceeded, we start an asynchronous preflush of pool pages */ ulint max_modified_age_sync; /*!< when this recommended value for lsn - buf_pool_get_oldest_modification() is exceeded, we start a synchronous preflush of pool pages */ ulint adm_checkpoint_interval; /*!< administrator-specified checkpoint interval in terms of log growth in bytes; the interval actually used by the database can be smaller */ ulint max_checkpoint_age_async; /*!< when this checkpoint age is exceeded we start an asynchronous writing of a new checkpoint */ ulint max_checkpoint_age; /*!< this is the maximum allowed value for lsn - last_checkpoint_lsn when a new query step is started */ ib_uint64_t next_checkpoint_no; /*!< next checkpoint number */ ib_uint64_t last_checkpoint_lsn; /*!< latest checkpoint lsn */ ib_uint64_t next_checkpoint_lsn; /*!< next checkpoint lsn */ ulint n_pending_checkpoint_writes; /*!< number of currently pending checkpoint writes */ rw_lock_t checkpoint_lock;/*!< this latch is x-locked when a checkpoint write is running; a thread should wait for this without owning the log mutex */ #endif /* !UNIV_HOTBACKUP */ byte* checkpoint_buf_ptr;/* unaligned checkpoint header */ byte* checkpoint_buf; /*!< checkpoint header is read to this buffer */ /* @} */ #ifdef UNIV_LOG_ARCHIVE /** Fields involved in archiving @{ */ ulint archiving_state;/*!< LOG_ARCH_ON, LOG_ARCH_STOPPING LOG_ARCH_STOPPED, LOG_ARCH_OFF */ ib_uint64_t archived_lsn; /*!< archiving has advanced to this lsn */ ulint max_archived_lsn_age_async; /*!< recommended maximum age of archived_lsn, before we start asynchronous copying to the archive */ ulint max_archived_lsn_age; /*!< maximum allowed age for archived_lsn */ ib_uint64_t next_archived_lsn;/*!< during an archive write, until the write is completed, we store the next value for archived_lsn here: the write completion function then sets the new value to archived_lsn */ ulint archiving_phase;/*!< LOG_ARCHIVE_READ or LOG_ARCHIVE_WRITE */ ulint n_pending_archive_ios; /*!< number of currently pending reads or writes in archiving */ rw_lock_t archive_lock; /*!< this latch is x-locked when an archive write is running; a thread should wait for this without owning the log mutex */ ulint archive_buf_size;/*!< size of archive_buf */ byte* archive_buf; /*!< log segment is written to the archive from this buffer */ os_event_t archiving_on; /*!< if archiving has been stopped, a thread can wait for this event to become signaled */ /* @} */ #endif /* UNIV_LOG_ARCHIVE */ ib_uint64_t tracked_lsn; /*!< log tracking has advanced to this lsn. Field accessed atomically where 64-bit atomic ops are supported, protected by the log sys mutex otherwise. */ }; /** Test if flush order mutex is owned. */ #define log_flush_order_mutex_own() \ mutex_own(&log_sys->log_flush_order_mutex) /** Acquire the flush order mutex. */ #define log_flush_order_mutex_enter() do { \ mutex_enter(&log_sys->log_flush_order_mutex); \ } while (0) /** Release the flush order mutex. */ # define log_flush_order_mutex_exit() do { \ mutex_exit(&log_sys->log_flush_order_mutex); \ } while (0) #ifdef UNIV_LOG_ARCHIVE /** Archiving state @{ */ #define LOG_ARCH_ON 71 #define LOG_ARCH_STOPPING 72 #define LOG_ARCH_STOPPING2 73 #define LOG_ARCH_STOPPED 74 #define LOG_ARCH_OFF 75 /* @} */ #endif /* UNIV_LOG_ARCHIVE */ #ifndef UNIV_NONINL #include "log0log.ic" #endif #endif