我有一个Ubuntu 14.04 Droplet，内存为2GB，在DigitalOcean上有2个cpu，一个LAMP堆栈，我用ubuntu创建了一个Docker容器：trusty image。
出现此问题后，我在Droplet（而非docker容器）上创建了1GB的swap，并在innodb_buffer_pool_size=64M部分的/etc/mysql/my.cnf内设置了[mysqld]。
我已经以这种方式安装了MySQL（来自我的Dockerfile）：
# Install MySQL
RUN echo mysql-server-5.6 mysql-server/root_password password $mysql_root_password | debconf-set-selections;\
echo mysql-server-5.6 mysql-server/root_password_again password $mysql_root_password | debconf-set-selections;\
apt-get install -y mysql-server-5.6
我用这个bash脚本创建了交换（$ 1是第一个获取脚本的参数）：
#!/usr/bin/env bash
# Disable case sensitivity
shopt -s nocasematch
if [[ ! -z $1 && ! $1 =~ false && $1 =~ ^[0-9]*$ ]]; then
echo ">>> Setting up Swap ($1 MB)"
# Create the Swap file
sudo fallocate -l $1M /swapfile
# Set the correct Swap permissions
sudo chmod 600 /swapfile
# Setup Swap space
sudo mkswap /swapfile
# Enable Swap space
sudo swapon /swapfile
# Make the Swap file permanent
sudo echo "/swapfile none swap sw 0 0" | sudo tee -a /etc/fstab
# Add some swap settings:
# vm.swappiness=10: Means that there wont be a Swap file until memory hits 90% useage
# vm.vfs_cache_pressure=50: read http://rudd-o.com/linux-and-free-software/tales-from-responsivenessland-why-linux-feels-slow-and-how-to-fix-that
sudo printf "vm.swappiness=10\nvm.vfs_cache_pressure=50" | sudo tee -a /etc/sysctl.conf && sudo sysctl -p
fi
这是my.cnf文件：
#
# The MySQL database server configuration file.
#
# You can copy this to one of:
# - "/etc/mysql/my.cnf" to set global options,
# - "~/.my.cnf" to set user-specific options.
#
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html
# This will be passed to all mysql clients
# It has been reported that passwords should be enclosed with ticks/quotes
# escpecially if they contain "#" chars...
# Remember to edit /etc/mysql/debian.cnf when changing the socket location.
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock
# Here is entries for some specific programs
# The following values assume you have at least 32M ram
# This was formally known as [safe_mysqld]. Both versions are currently parsed.
[mysqld_safe]
socket = /var/run/mysqld/mysqld.sock
nice = 0
[mysqld]
innodb_buffer_pool_size=64M
#
# * Basic Settings
#
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
lc-messages-dir = /usr/share/mysql
skip-external-locking
#
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
bind-address = 127.0.0.1
#
# * Fine Tuning
#
key_buffer = 16M
max_allowed_packet = 16M
thread_stack = 192K
thread_cache_size = 8
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover = BACKUP
#max_connections = 100
#table_cache = 64
#thread_concurrency = 10
#
# * Query Cache Configuration
#
query_cache_limit = 1M
query_cache_size = 16M
#
# * Logging and Replication
#
# Both location gets rotated by the cronjob.
# Be aware that this log type is a performance killer.
# As of 5.1 you can enable the log at runtime!
#general_log_file = /var/log/mysql/mysql.log
#general_log = 1
#
# Error log - should be very few entries.
#
log_error = /var/log/mysql/error.log
#
# Here you can see queries with especially long duration
#log_slow_queries = /var/log/mysql/mysql-slow.log
#long_query_time = 2
#log-queries-not-using-indexes
#
# The following can be used as easy to replay backup logs or for replication.
# note: if you are setting up a replication slave, see README.Debian about
# other settings you may need to change.
#server-id = 1
#log_bin = /var/log/mysql/mysql-bin.log
expire_logs_days = 10
max_binlog_size = 100M
#binlog_do_db = include_database_name
#binlog_ignore_db = include_database_name
#
# * InnoDB
#
# InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/.
# Read the manual for more InnoDB related options. There are many!
#
# * Security Features
#
# Read the manual, too, if you want chroot!
# chroot = /var/lib/mysql/
#
# For generating SSL certificates I recommend the OpenSSL GUI "tinyca".
#
# ssl-ca=/etc/mysql/cacert.pem
# ssl-cert=/etc/mysql/server-cert.pem
# ssl-key=/etc/mysql/server-key.pem
[mysqldump]
quick
quote-names
max_allowed_packet = 16M
[mysql]
#no-auto-rehash # faster start of mysql but no tab completition
[isamchk]
key_buffer = 16M
#
# * IMPORTANT: Additional settings that can override those from this file!
# The files must end with '.cnf', otherwise they'll be ignored.
#
!includedir /etc/mysql/conf.d/
这是来自/var/log/mysql/error.log的MySQL错误日志：
160719 10:57:36 mysqld_safe Number of processes running now: 0
160719 10:57:36 mysqld_safe mysqld restarted
2016-07-19 10:57:41 0 [Warning] Using unique option prefix key_buffer instead of key_buffer_size is deprecated and will be removed in a future release. Please use the full name instead.
2016-07-19 10:57:41 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2016-07-19 10:57:41 0 [Note] /usr/sbin/mysqld (mysqld 5.6.30-0ubuntu0.14.04.1) starting as process 15342 ...
2016-07-19 10:57:41 15342 [Warning] Buffered warning: Performance schema disabled (reason: init failed).
2016-07-19 10:57:41 15342 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future release. Please use the full name instead.
2016-07-19 10:57:41 15342 [Note] Plugin 'FEDERATED' is disabled.
2016-07-19 10:57:42 15342 [ERROR] Function 'innodb' already exists
2016-07-19 10:57:42 15342 [Warning] Couldn't load plugin named 'innodb' with soname 'ha_innodb.so'.
2016-07-19 10:57:42 15342 [ERROR] Function 'federated' already exists
2016-07-19 10:57:42 15342 [Warning] Couldn't load plugin named 'federated' with soname 'ha_federated.so'.
2016-07-19 10:57:42 15342 [ERROR] Function 'blackhole' already exists
2016-07-19 10:57:42 15342 [Warning] Couldn't load plugin named 'blackhole' with soname 'ha_blackhole.so'.
2016-07-19 10:57:42 15342 [ERROR] Function 'archive' already exists
2016-07-19 10:57:42 15342 [Warning] Couldn't load plugin named 'archive' with soname 'ha_archive.so'.
2016-07-19 10:57:42 15342 [Note] InnoDB: Using atomics to ref count buffer pool pages
2016-07-19 10:57:42 15342 [Note] InnoDB: The InnoDB memory heap is disabled
2016-07-19 10:57:42 15342 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-07-19 10:57:42 15342 [Note] InnoDB: Memory barrier is not used
2016-07-19 10:57:42 15342 [Note] InnoDB: Compressed tables use zlib 1.2.8
2016-07-19 10:57:42 15342 [Note] InnoDB: Using Linux native AIO
2016-07-19 10:57:42 15342 [Note] InnoDB: Using CPU crc32 instructions
2016-07-19 10:57:43 15342 [Note] InnoDB: Initializing buffer pool, size = 64.0M
2016-07-19 10:57:44 15342 [Note] InnoDB: Completed initialization of buffer pool
2016-07-19 10:57:50 15342 [Note] InnoDB: Highest supported file format is Barracuda.
2016-07-19 10:57:50 15342 [Note] InnoDB: Log scan progressed past the checkpoint lsn 10499122273
2016-07-19 10:57:50 15342 [Note] InnoDB: Database was not shutdown normally!
2016-07-19 10:57:50 15342 [Note] InnoDB: Starting crash recovery.
2016-07-19 10:57:50 15342 [Note] InnoDB: Reading tablespace information from the .ibd files...
2016-07-19 10:59:45 15342 [Note] InnoDB: Restoring possible half-written data pages
2016-07-19 10:59:45 15342 [Note] InnoDB: from the doublewrite buffer...
Killed
160719 11:00:02 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
160719 14:26:39 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
2016-07-19 14:26:40 0 [Warning] Using unique option prefix key_buffer instead of key_buffer_size is deprecated and will be removed in a future release. Please use the full name instead.
2016-07-19 14:26:40 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2016-07-19 14:26:40 0 [Note] /usr/sbin/mysqld (mysqld 5.6.30-0ubuntu0.14.04.1) starting as process 18656 ...
2016-07-19 14:26:40 18656 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future release. Please use the full name instead.
2016-07-19 14:26:40 18656 [Note] Plugin 'FEDERATED' is disabled.
2016-07-19 14:26:40 18656 [ERROR] Function 'innodb' already exists
2016-07-19 14:26:40 18656 [Warning] Couldn't load plugin named 'innodb' with soname 'ha_innodb.so'.
2016-07-19 14:26:40 18656 [ERROR] Function 'federated' already exists
2016-07-19 14:26:40 18656 [Warning] Couldn't load plugin named 'federated' with soname 'ha_federated.so'.
2016-07-19 14:26:40 18656 [ERROR] Function 'blackhole' already exists
2016-07-19 14:26:40 18656 [Warning] Couldn't load plugin named 'blackhole' with soname 'ha_blackhole.so'.
2016-07-19 14:26:40 18656 [ERROR] Function 'archive' already exists
2016-07-19 14:26:40 18656 [Warning] Couldn't load plugin named 'archive' with soname 'ha_archive.so'.
2016-07-19 14:26:40 18656 [Note] InnoDB: Using atomics to ref count buffer pool pages
2016-07-19 14:26:40 18656 [Note] InnoDB: The InnoDB memory heap is disabled
2016-07-19 14:26:40 18656 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-07-19 14:26:40 18656 [Note] InnoDB: Memory barrier is not used
2016-07-19 14:26:40 18656 [Note] InnoDB: Compressed tables use zlib 1.2.8
2016-07-19 14:26:40 18656 [Note] InnoDB: Using Linux native AIO
2016-07-19 14:26:40 18656 [Note] InnoDB: Using CPU crc32 instructions
2016-07-19 14:26:40 18656 [Note] InnoDB: Initializing buffer pool, size = 64.0M
2016-07-19 14:26:40 18656 [Note] InnoDB: Completed initialization of buffer pool
2016-07-19 14:26:40 18656 [Note] InnoDB: Highest supported file format is Barracuda.
2016-07-19 14:26:40 18656 [Note] InnoDB: Log scan progressed past the checkpoint lsn 10499122273
2016-07-19 14:26:40 18656 [Note] InnoDB: Database was not shutdown normally!
2016-07-19 14:26:40 18656 [Note] InnoDB: Starting crash recovery.
2016-07-19 14:26:40 18656 [Note] InnoDB: Reading tablespace information from the .ibd files...
2016-07-19 14:26:41 18656 [Note] InnoDB: Restoring possible half-written data pages
2016-07-19 14:26:41 18656 [Note] InnoDB: from the doublewrite buffer...
InnoDB: Doing recovery: scanned up to log sequence number 10499122881
2016-07-19 14:26:41 18656 [Note] InnoDB: Starting an apply batch of log records to the database...
InnoDB: Progress in percent: 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
InnoDB: Apply batch completed
2016-07-19 14:26:42 18656 [Note] InnoDB: 128 rollback segment(s) are active.
2016-07-19 14:26:42 18656 [Note] InnoDB: Waiting for purge to start
2016-07-19 14:26:42 18656 [Note] InnoDB: 5.6.30 started; log sequence number 10499122881
2016-07-19 14:26:42 18656 [Note] Server hostname (bind-address): '127.0.0.1'; port: 3306
2016-07-19 14:26:42 18656 [Note] - '127.0.0.1' resolves to '127.0.0.1';
2016-07-19 14:26:42 18656 [Note] Server socket created on IP: '127.0.0.1'.
2016-07-19 14:26:42 18656 [Note] Event Scheduler: Loaded 0 events
2016-07-19 14:26:42 18656 [Note] /usr/sbin/mysqld: ready for connections.
Version: '5.6.30-0ubuntu0.14.04.1' socket: '/var/run/mysqld/mysqld.sock' port: 3306 (Ubuntu)
交换工作正常，我检查了cat /proc/swaps和free -m命令，读取MySQL错误日志似乎innodb_buffer_pool_size参数工作正常。
我做错了什么？
感谢。