log0log.c

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		/* Wait for the checkpoint write to complete */
		rw_lock_s_lock(&(log_sys->checkpoint_lock));
		rw_lock_s_unlock(&(log_sys->checkpoint_lock));
	}

	return(TRUE);
}

/********************************************************************
Makes a checkpoint at a given lsn or later. */

void
log_make_checkpoint_at(
/*===================*/
	dulint	lsn,		/* in: make a checkpoint at this or a later
				lsn, if ut_dulint_max, makes a checkpoint at
				the latest lsn */
	ibool	write_always)	/* in: the function normally checks if the
				the new checkpoint would have a greater
				lsn than the previous one: if not, then no
				physical write is done; by setting this
				parameter TRUE, a physical write will always be
				made to log files */
{
	ibool	success;

	/* Preflush pages synchronously */

	success = FALSE;
	
	while (!success) {
		success = log_preflush_pool_modified_pages(lsn, TRUE);
	}

	success = FALSE;
	
	while (!success) {
		success = log_checkpoint(TRUE, write_always);
	}
}

/********************************************************************
Tries to establish a big enough margin of free space in the log groups, such
that a new log entry can be catenated without an immediate need for a
checkpoint. NOTE: this function may only be called if the calling thread
owns no synchronization objects! */
static
void
log_checkpoint_margin(void)
/*=======================*/
{
	log_t*	log		= log_sys;
	ulint	age;
	ulint	checkpoint_age;
	ulint	advance;
	dulint	oldest_lsn;
	ibool	sync;
	ibool	checkpoint_sync;
	ibool	do_checkpoint;
	ibool	success;
loop:
	sync = FALSE;
	checkpoint_sync = FALSE;
	do_checkpoint = FALSE;

	mutex_enter(&(log->mutex));

	if (log->check_flush_or_checkpoint == FALSE) {
		mutex_exit(&(log->mutex));

		return;
	}	

	oldest_lsn = log_buf_pool_get_oldest_modification();

	age = ut_dulint_minus(log->lsn, oldest_lsn);
	
	if (age > log->max_modified_age_sync) {

		/* A flush is urgent: we have to do a synchronous preflush */

		sync = TRUE;
		advance = 2 * (age - log->max_modified_age_sync);
	} else if (age > log->max_modified_age_async) {

		/* A flush is not urgent: we do an asynchronous preflush */
		advance = age - log->max_modified_age_async;
	} else {
		advance = 0;
	}

	checkpoint_age = ut_dulint_minus(log->lsn, log->last_checkpoint_lsn);

	if (checkpoint_age > log->max_checkpoint_age) {
		/* A checkpoint is urgent: we do it synchronously */
	
		checkpoint_sync = TRUE;

		do_checkpoint = TRUE;

	} else if (checkpoint_age > log->max_checkpoint_age_async) {
		/* A checkpoint is not urgent: do it asynchronously */

		do_checkpoint = TRUE;

		log->check_flush_or_checkpoint = FALSE;
	} else {
		log->check_flush_or_checkpoint = FALSE;
	}
	
	mutex_exit(&(log->mutex));

	if (advance) {
		dulint	new_oldest = ut_dulint_add(oldest_lsn, advance);

		success = log_preflush_pool_modified_pages(new_oldest, sync);

		/* If the flush succeeded, this thread has done its part
		and can proceed. If it did not succeed, there was another
		thread doing a flush at the same time. If sync was FALSE,
		the flush was not urgent, and we let this thread proceed.
		Otherwise, we let it start from the beginning again. */

		if (sync && !success) {
			mutex_enter(&(log->mutex));

			log->check_flush_or_checkpoint = TRUE;
	
			mutex_exit(&(log->mutex));
			goto loop;
		}
	}

	if (do_checkpoint) {
		log_checkpoint(checkpoint_sync, FALSE);

		if (checkpoint_sync) {

			goto loop;
		}
	}
}

/**********************************************************
Reads a specified log segment to a buffer. */

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 */
	dulint		start_lsn,	/* in: read area start */
	dulint		end_lsn)	/* in: read area end */
{
	ulint	len;
	ulint	source_offset;
	ibool	sync;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(log_sys->mutex)));
#endif /* UNIV_SYNC_DEBUG */

	sync = FALSE;

	if (type == LOG_RECOVER) {
		sync = TRUE;
	}
loop:
	source_offset = log_group_calc_lsn_offset(start_lsn, group);

	len = ut_dulint_minus(end_lsn, start_lsn);

	ut_ad(len != 0);

	if ((source_offset % group->file_size) + len > group->file_size) {

		len = group->file_size - (source_offset % group->file_size);
	}

#ifdef UNIV_LOG_ARCHIVE
	if (type == LOG_ARCHIVE) {
	
		log_sys->n_pending_archive_ios++;
	}
#endif /* UNIV_LOG_ARCHIVE */

	log_sys->n_log_ios++;
	
	fil_io(OS_FILE_READ | OS_FILE_LOG, sync, group->space_id,
		source_offset / UNIV_PAGE_SIZE, source_offset % UNIV_PAGE_SIZE,
		len, buf, NULL);

	start_lsn = ut_dulint_add(start_lsn, len);
	buf += len;

	if (ut_dulint_cmp(start_lsn, end_lsn) != 0) {

		goto loop;
	}
}

#ifdef UNIV_LOG_ARCHIVE
/**********************************************************
Generates an archived log file name. */

void
log_archived_file_name_gen(
/*=======================*/
	char*	buf,	/* in: buffer where to write */
	ulint	id __attribute__((unused)),
			/* in: group id;
			currently we only archive the first group */
	ulint	file_no)/* in: file number */
{
	sprintf(buf, "%sib_arch_log_%010lu", srv_arch_dir, (ulong) file_no);
}

/**********************************************************
Writes a log file header to a log file space. */
static
void
log_group_archive_file_header_write(
/*================================*/
	log_group_t*	group,		/* in: log group */
	ulint		nth_file,	/* in: header to the nth file in the
					archive log file space */
	ulint		file_no,	/* in: archived file number */
	dulint		start_lsn)	/* in: log file data starts at this
					lsn */
{
	byte*	buf;
	ulint	dest_offset;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(log_sys->mutex)));
#endif /* UNIV_SYNC_DEBUG */

	ut_a(nth_file < group->n_files);

	buf = *(group->archive_file_header_bufs + nth_file);

	mach_write_to_4(buf + LOG_GROUP_ID, group->id);
	mach_write_to_8(buf + LOG_FILE_START_LSN, start_lsn);
	mach_write_to_4(buf + LOG_FILE_NO, file_no);

	mach_write_to_4(buf + LOG_FILE_ARCH_COMPLETED, FALSE);

	dest_offset = nth_file * group->file_size;

	log_sys->n_log_ios++;
	
	fil_io(OS_FILE_WRITE | OS_FILE_LOG, TRUE, group->archive_space_id,
				dest_offset / UNIV_PAGE_SIZE,
				dest_offset % UNIV_PAGE_SIZE,
				2 * OS_FILE_LOG_BLOCK_SIZE,
				buf, &log_archive_io);
}

/**********************************************************
Writes a log file header to a completed archived log file. */
static
void
log_group_archive_completed_header_write(
/*=====================================*/
	log_group_t*	group,		/* in: log group */
	ulint		nth_file,	/* in: header to the nth file in the
					archive log file space */
	dulint		end_lsn)	/* in: end lsn of the file */
{
	byte*	buf;
	ulint	dest_offset;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(log_sys->mutex)));
#endif /* UNIV_SYNC_DEBUG */
	ut_a(nth_file < group->n_files);

	buf = *(group->archive_file_header_bufs + nth_file);

	mach_write_to_4(buf + LOG_FILE_ARCH_COMPLETED, TRUE);
	mach_write_to_8(buf + LOG_FILE_END_LSN, end_lsn);

	dest_offset = nth_file * group->file_size + LOG_FILE_ARCH_COMPLETED;

	log_sys->n_log_ios++;
	
	fil_io(OS_FILE_WRITE | OS_FILE_LOG, TRUE, group->archive_space_id,
				dest_offset / UNIV_PAGE_SIZE,
				dest_offset % UNIV_PAGE_SIZE,
				OS_FILE_LOG_BLOCK_SIZE,
				buf + LOG_FILE_ARCH_COMPLETED,
				&log_archive_io);
}

/**********************************************************
Does the archive writes for a single log group. */
static
void
log_group_archive(
/*==============*/
	log_group_t*	group)	/* in: log group */
{
	os_file_t file_handle;
	dulint	start_lsn;
	dulint	end_lsn;
	char	name[1024];
	byte*	buf;
	ulint	len;
	ibool	ret;
	ulint	next_offset;
	ulint	n_files;
	ulint	open_mode;
	
#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(log_sys->mutex)));
#endif /* UNIV_SYNC_DEBUG */

	start_lsn = log_sys->archived_lsn;

	ut_a(ut_dulint_get_low(start_lsn) % OS_FILE_LOG_BLOCK_SIZE == 0);

	end_lsn = log_sys->next_archived_lsn;

	ut_a(ut_dulint_get_low(end_lsn) % OS_FILE_LOG_BLOCK_SIZE == 0);

	buf = log_sys->archive_buf;

	n_files = 0;

	next_offset = group->archived_offset;
loop:				
	if ((next_offset % group->file_size == 0)
	    || (fil_space_get_size(group->archive_space_id) == 0)) {

		/* Add the file to the archive file space; create or open the
		file */

		if (next_offset % group->file_size == 0) {
			open_mode = OS_FILE_CREATE;
		} else {
			open_mode = OS_FILE_OPEN;
		}
	
		log_archived_file_name_gen(name, group->id,
					group->archived_file_no + n_files);

		file_handle = os_file_create(name, open_mode, OS_FILE_AIO,
						OS_DATA_FILE, &ret);

		if (!ret && (open_mode == OS_FILE_CREATE)) {
			file_handle = os_file_create(name, OS_FILE_OPEN,
					OS_FILE_AIO, OS_DATA_FILE, &ret);
		}

		if (!ret) {
			fprintf(stderr,
		"InnoDB: Cannot create or open archive log file %s.\n"
		"InnoDB: Cannot continue operation.\n"
		"InnoDB: Check that the log archive directory exists,\n"
		"InnoDB: you have access rights to it, and\n"
		"InnoDB: there is space available.\n", name);
			exit(1);
		}

#ifdef UNIV_DEBUG
		if (log_debug_writes) {
			fprintf(stderr, "Created archive file %s\n", name);
		}
#endif /* UNIV_DEBUG */

		ret = os_file_close(file_handle);
	
		ut_a(ret);
	
		/* Add the archive file as a node to the space */
		
		fil_node_create(name, group->file_size / UNIV_PAGE_SIZE,
					group->archive_space_id, FALSE);

		if (next_offset % group->file_size == 0) {
			log_group_archive_file_header_write(group, n_files,
					group->archived_file_no + n_files,
					start_lsn);

			next_offset += LOG_FILE_HDR_SIZE;
		}				
	}

	len = ut_dulint_minus(end_lsn, start_lsn);

	if (group->file_size < (next_offset % group->file_size) + len) {

		len = group->file_size - (next_offset % group->file_size);
	}

#ifdef UNIV_DEBUG
	if (log_debug_writes) {
		fprintf(stderr,
		"Archiving starting at lsn %lu %lu, len %lu to group %lu\n",
					(ulong) ut_dulint_get_high(start_lsn),
					(ulong) ut_dulint_get_low(start_lsn),
					(ulong) len, (ulong) group->id);
	}
#endif /* UNIV_DEBUG */

	log_sys->n_pending_archive_ios++;

	log_sys->n_log_ios++;
	
	fil_io(OS_FILE_WRITE | OS_FILE_LOG, FALSE, group->archive_space_id,
		next_offset / UNIV_PAGE_SIZE, next_offset % UNIV_PAGE_SIZE,
		ut_calc_align(len, OS_FILE_LOG_BLOCK_SIZE), buf,
							&log_archive_io);

	start_lsn = ut_dulint_add(start_lsn, len);
	next_offset += len;
	buf += len;

	if (next_offset % group->file_size == 0) {
		n_files++;
	}

	if (ut_dulint_cmp(end_lsn, start_lsn) != 0) {
	
		goto loop;
	}

	group->next_archived_file_no = group->archived_file_no + n_files;
	group->next_archived_offset = next_offset % group->file_size;

	ut_a(group->next_archived_offset % OS_FILE_LOG_BLOCK_SIZE == 0);
}

/*********************************************************
(Writes to the archive of each log group.) Currently, only the first
group is archived. */
static
void
log_archive_groups(void)
/*====================*/
{
	log_group_t*	group;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(log_sys->mutex)));
#endif /* UNIV_SYNC_DEBUG */

	group = UT_LIST_GET_FIRST(log_sys->log_groups);

	log_group_archive(group);
}

/*********************************************************
Completes the archiving write phase for (each log group), currently,
the first log group. */
static
void
log_archive_write_complete_groups(void)
/*===================================*/
{
	log_group_t*	group;
	ulint		end_offset;
	ulint		trunc_files;
	ulint		n_files;
	dulint		start_lsn;
	dulint		end_lsn;
	ulint		i;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(log_sys->mutex)));
#endif /* UNIV_SYNC_DEBUG */

	group = UT_LIST_GET_FIRST(log_sys->log_groups);

	group->archived_file_no = group->next_archived_file_no;
	group->archived_offset = group->next_archived_offset;

	/* Truncate from the archive file space all but the last
	file, or if it has been written full, all files */

	n_files = (UNIV_PAGE_SIZE
			    * fil_space_get_size(group->archive_space_id))
			    				/ group->file_size;
	ut_ad(n_files > 0);
		
	end_offset = group->archived_offset;

	if (end_offset % group->file_size == 0) {
		
		trunc_files = n_files;
	} else {
		trunc_files