收到報警，某個端口備份失敗，檢視備份日志如下，顯示有DDL操作導緻的備份中斷，檢視當時的二進制日志，當時執行了一條添加字段的sql語句。目前隻能重新執行備份，并修改備份時間，避免再發生類似情況。
MySQL：5.7.11
xtrabackup：2.4.5
查找到官方修複bug的情況：
Running DDL statements onPercona Server5.7 during the backup process could in some cases lead to failure while preparing the backup. Bug fixed#1555626.
MySQL5.7 can sometimes skip redo logging when creating an index. If suchALTER TABLEis being issued during the backup, the backup would be inconsistent.xtrabackupwill now abort with error message if suchALTER TABLEhas been done during the backup. Bug fixed#1582345.
是以說這種情況是正常的，應盡量避免在備份時執行這些sql
備份日志：InnoDB: Last flushed lsn: 340748764928 load_index lsn 340748904772
# 一個DDL操作已經執行(未記錄redo日志)。影響到的行可能未落地，PXB不能確定備份的一緻性，請重試
[FATAL] InnoDB: An optimized(without redo logging) DDLoperation has been performed. All modified pages may not have been flushed to the disk yet.
PXB will not be able take a consistent backup. Retry the backup operation
# 斷言失敗
2017-06-01 08:43:19 0x7f396ee27700 InnoDB: Assertion failure in thread 139884650198784 in file ut0ut.cc line 916
# 故意生成一個記憶體陷阱，使備份中斷
InnoDB: We intentionally generate a memory trap.
InnoDB: Submit a detailed bug report to http://bugs.mysql.com.
InnoDB: If you get repeated assertion failures or crashes, even
InnoDB: immediately after the mysqld startup, there may be
InnoDB: corruption in the InnoDB tablespace. Please refer to
InnoDB: http://dev.mysql.com/doc/refman/5.7/en/forcing-innodb-recovery.html
InnoDB: about forcing recovery.
00:43:19 UTC - xtrabackup got signal 6 ;
This could be because you hit a bug or data is corrupted.
This error can also be caused by malfunctioning hardware.
Attempting to collect some information that could help diagnose the problem.
As this is a crash and something is definitely wrong, the information
collection process might fail.
Thread pointer: 0x0
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong...
stack_bottom = 0 thread_stack 0x10000
/usr/local/xtrabackup/bin/innobackupex(my_print_stacktrace+0x35)[0xd55c45]
/usr/local/xtrabackup/bin/innobackupex(handle_fatal_signal+0x273)[0xb0d5a3]
/lib64/libpthread.so.0[0x36ac20f710]
/lib64/libc.so.6(gsignal+0x35)[0x36abe32625]
/lib64/libc.so.6(abort+0x175)[0x36abe33e05]
/usr/local/xtrabackup/bin/innobackupex[0x7bfbe5]
/usr/local/xtrabackup/bin/innobackupex(_ZN2ib5fatalD1Ev+0xb3)[0x837743]
/usr/local/xtrabackup/bin/innobackupex[0x8af4a1]
/usr/local/xtrabackup/bin/innobackupex(_Z19recv_parse_log_recsm7store_tb+0x4df)[0x8b20ef]
/usr/local/xtrabackup/bin/innobackupex[0x763b60]
/usr/local/xtrabackup/bin/innobackupex[0x764176]
/usr/local/xtrabackup/bin/innobackupex[0x764523]
/lib64/libpthread.so.0[0x36ac2079d1]
/lib64/libc.so.6(clone+0x6d)[0x36abee88fd]
Please report a bug at https://bugs.launchpad.net/percona-xtrabackup