MySQL Bug一例-----ibuf cursor restoration fails

产生原因：

1. 开启change buffer（innodb_change_buffering）
2. 对表进行大量delete 操作
3. 对相同表进行truncate

bug名称：ibuf cursor restoration fails（change buffer 游标存储失败）
改进：升级版本至 5.7.31 或者 8.0.21

2020-07-07T16:18:52.385927+08:00 0 [ERROR] InnoDB: Submit a detailed bug report to http://bugs.mysql.com
PHYSICAL RECORD: n_fields 10; 1-byte offsets; info bits 0
 0: len 4; hex 000007fa; asc     ;;
 1: len 1; hex 00; asc  ;;
 2: len 4; hex 0000076b; asc    k;;
 3: len 30; hex 000100010dfe002180218608000800008603000480000c0f00b480218603; asc        ! !                 !  ; (total 40 bytes);
 4: len 11; hex 3138333638343335333339; asc 18368435339;;
 5: len 8; hex 8000000000000000; asc         ;;
 6: len 4; hex 8007117f; asc     ;;
 7: len 15; hex 3131352e3233382e3134302e313436; asc 1.1.1.1;;
 8: len 4; hex 81343d03; asc  4= ;;
 9: len 4; hex 80024fb0; asc   O ;;
PHYSICAL RECORD: n_fields 10; 1-byte offsets; info bits 0
 0: len 4; hex 000007fa; asc     ;;
 1: len 1; hex 00; asc  ;;
 2: len 4; hex 0000076b; asc    k;;
 3: len 30; hex 000100010dfe002180218608000800008603000480000c0f00b480218603; asc        ! !                 !  ; (total 40 bytes);
 4: len 11; hex 3138333638343335333339; asc 13800138000;;
 5: len 8; hex 8000000000000000; asc         ;;
 6: len 4; hex 8007117f; asc     ;;
 7: len 15; hex 3131352e3233382e3134302e313436; asc 2.2.2.2;;
 8: len 4; hex 81343d03; asc  4= ;;
 9: len 4; hex 80024fb0; asc   O ;;
DATA TUPLE: 3 fields;
 0: len 4; hex 00000845; asc    E;;
 1: len 1; hex 00; asc  ;;
 2: len 4; hex 00000302; asc     ;;
PHYSICAL RECORD: n_fields 9; 1-byte offsets; info bits 32
 0: len 4; hex 00000845; asc    E;;
 1: len 1; hex 00; asc  ;;
 2: len 4; hex 00000302; asc     ;;
 3: len 30; hex 002501010c0f005a80210dfe001e80218608000880000dfe009600218603; asc  %     Z !     !           !  ; (total 34 bytes);
 4: len 10; hex 7777772e31372e636f6d; asc www.aikaiyuan.com;;
 5: len 10; hex 68352020202020202020; asc h5        ;;
 6: len 8; hex 80000000419517f1; asc     A   ;;
 7: len 30; hex 2f313130303239303033332f62656e7a2f732f35323734392e68746d6c20; asc /123.html ; (total 50 bytes);
 8: len 4; hex 8037f31e; asc  7  ;;
2020-07-07T16:18:52.417979+08:00 0 [ERROR] [FATAL] InnoDB: Failed to restore ibuf position.
2020-07-07 16:18:52 0x7f6a61bfd700  InnoDB: Assertion failure in thread 140094883223296 in file ut0ut.cc line 947
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.
08:18:52 UTC - mysqld got signal 6 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. 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.
Please help us make Percona Server better by reporting any
bugs at http://bugs.percona.com/

key_buffer_size=763363328
read_buffer_size=1048576
max_used_connections=636
max_threads=513
thread_count=35
connection_count=18
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 1852078 K  bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

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 0x40000
/usr/local/mysql57/bin/mysqld(my_print_stacktrace+0x2c)[0xedf27c]
/usr/local/mysql57/bin/mysqld(handle_fatal_signal+0x461)[0xd206f1]
/lib64/libpthread.so.0(+0xf5f0)[0x7f6ae815c5f0]
/lib64/libc.so.6(gsignal+0x37)[0x7f6ae625a337]
/lib64/libc.so.6(abort+0x148)[0x7f6ae625ba28]
/usr/local/mysql57/bin/mysqld[0x777028]
/usr/local/mysql57/bin/mysqld(_ZN2ib5fatalD1Ev+0xee)[0x1182c9e]
/usr/local/mysql57/bin/mysqld[0x10126de]
/usr/local/mysql57/bin/mysqld[0x10145a1]
/usr/local/mysql57/bin/mysqld(_Z29ibuf_merge_or_delete_for_pageP11buf_block_tRK9page_id_tPK11page_size_tm+0xbf8)[0x101b918]
/usr/local/mysql57/bin/mysqld(_Z20buf_page_io_completeP10buf_page_tb+0x13bc)[0x11c90ac]
/usr/local/mysql57/bin/mysqld(_Z12fil_aio_waitm+0x216)[0x1241ab6]
/usr/local/mysql57/bin/mysqld(io_handler_thread+0xc0)[0x1125410]
/lib64/libpthread.so.0(+0x7e65)[0x7f6ae8154e65]
/lib64/libc.so.6(clone+0x6d)[0x7f6ae632288d]
You may download the Percona Server operations manual by visiting
http://www.percona.com/software/percona-server/. You may find information