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larger LSN appears in innobackupex prepare output

apple0315apple0315 EntrantCurrent User Role Beginner
First, I took a full backup.
cat xtrabackup_checkpoints I get:

backup_type = full-prepared
from_lsn = 0
to_lsn = 238403986
last_lsn = 238403993
compact = 0
recover_binlog_info = 0


Then, prepare the backup using innobackupex --apply-log .
Output:

160218 11:50:18 innobackupex: Starting the apply-log operation

IMPORTANT: Please check that the apply-log run completes successfully.
At the end of a successful apply-log run innobackupex
prints "completed OK!".

innobackupex version 2.3.3 based on MySQL server 5.6.24 Linux (x86_64) (revision id: 525ca7d)
xtrabackup: cd to /root/innobackup_2/.
xtrabackup: This target seems to be not prepared yet.
xtrabackup: xtrabackup_logfile detected: size=2097152, start_lsn=(238403986)
xtrabackup: using the following InnoDB configuration for recovery:
xtrabackup: innodb_data_home_dir = ./
xtrabackup: innodb_data_file_path = ibdata1:10M:autoextend
xtrabackup: innodb_log_group_home_dir = ./
xtrabackup: innodb_log_files_in_group = 1
xtrabackup: innodb_log_file_size = 2097152
xtrabackup: using the following InnoDB configuration for recovery:
xtrabackup: innodb_data_home_dir = ./
xtrabackup: innodb_data_file_path = ibdata1:10M:autoextend
xtrabackup: innodb_log_group_home_dir = ./
xtrabackup: innodb_log_files_in_group = 1
xtrabackup: innodb_log_file_size = 2097152
xtrabackup: Starting InnoDB instance for recovery.
xtrabackup: Using 104857600 bytes for buffer pool (set by --use-memory parameter)
InnoDB: Using atomics to ref count buffer pool pages
InnoDB: The InnoDB memory heap is disabled
InnoDB: Mutexes and rw_locks use GCC atomic builtins
InnoDB: Memory barrier is not used
InnoDB: Compressed tables use zlib 1.2.8
InnoDB: Using CPU crc32 instructions
InnoDB: Initializing buffer pool, size = 100.0M
InnoDB: Completed initialization of buffer pool
InnoDB: Highest supported file format is Barracuda.
InnoDB: Log scan progressed past the checkpoint lsn 238403986
InnoDB: Database was not shutdown normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages
InnoDB: from the doublewrite buffer...
InnoDB: Doing recovery: scanned up to log sequence number 238403993 (0%)
InnoDB: 128 rollback segment(s) are active.
InnoDB: Waiting for purge to start
InnoDB: 5.6.24 started; log sequence number 238403993
xtrabackup: Last MySQL binlog file position 481, file name mysql-bin.000002

xtrabackup: starting shutdown with innodb_fast_shutdown = 1
InnoDB: FTS optimize thread exiting.
InnoDB: Starting shutdown...
InnoDB: Shutdown completed; log sequence number 238405699
xtrabackup: using the following InnoDB configuration for recovery:
xtrabackup: innodb_data_home_dir = ./
xtrabackup: innodb_data_file_path = ibdata1:10M:autoextend
xtrabackup: innodb_log_group_home_dir = ./
xtrabackup: innodb_log_files_in_group = 2
xtrabackup: innodb_log_file_size = 50331648
InnoDB: Using atomics to ref count buffer pool pages
InnoDB: The InnoDB memory heap is disabled
InnoDB: Mutexes and rw_locks use GCC atomic builtins
InnoDB: Memory barrier is not used
InnoDB: Compressed tables use zlib 1.2.8
InnoDB: Using CPU crc32 instructions
InnoDB: Initializing buffer pool, size = 100.0M
InnoDB: Completed initialization of buffer pool
InnoDB: Setting log file ./ib_logfile101 size to 48 MB
InnoDB: Setting log file ./ib_logfile1 size to 48 MB
InnoDB: Renaming log file ./ib_logfile101 to ./ib_logfile0
InnoDB: New log files created, LSN=238405699
InnoDB: Highest supported file format is Barracuda.
InnoDB: 128 rollback segment(s) are active.
InnoDB: Waiting for purge to start
InnoDB: 5.6.24 started; log sequence number 238406156
xtrabackup: starting shutdown with innodb_fast_shutdown = 1
InnoDB: FTS optimize thread exiting.
InnoDB: Starting shutdown...
InnoDB: Shutdown completed; log sequence number 238406166
160218 11:50:22 completed OK!


Then I restored the database using the prepared bakup.
Then I inserted one record into a table.
Then I run show engine innodb status\G
Output:
---
LOG
---
Log sequence number 238405798
Log flushed up to 238405798
Pages flushed up to 238405798
Last checkpoint at 238405798
Max checkpoint age 80826164
Checkpoint age target 78300347
Modified age 0
Checkpoint age 0
0 pending log writes, 0 pending chkp writes
19 log i/o's done, 0.00 log i/o's/second


My question:

Why the green LSN is smaller than the red LSN. I can understand that the LSN will increase during the backup preparation. But new LSN in the restored database should start from the largest LSN generated in preparation which should be the red LSN I think. How come the green LSN is smaller than the red ones?

Thanks.
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