我正在尝试转储所有数据库，但它给出了错误“转储表时查询期间与 MySQL 服务器失去连接”并且文件始终达到781M。
我尝试设置最大允许数据包 = 512M以下[mysqld]及以下[mysqldump]在/etc/mysql/my.cnf，但是没用。我也试过设置为 1024M。没用。
我认为发生这种情况是因为 Apache 使用了几乎所有的 RAM，但我不太确定，因为当文件达到 781M 时我的转储总是停止。
/etc/mysql/my.cnf：
#
# 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
log_error=/var/log/mysql/mysql_error.log
[mysqld]
#
# * 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
language = /usr/share/mysql/english
skip-external-locking
log_error=/var/log/mysql/mysql_error.log
max_allowed_packet = 512M
# Replic
server-id=2
master-host=hostip
master-user=slaveusr
master-password=slavepass
master-port=3306
#
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
bind-address = 0.0.0.0
#
# * Fine Tuning
#
key_buffer = 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 logging goes to syslog due to
/etc/mysql/conf.d/mysqld_safe_syslog.cnf.
#
# 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 = 512M
[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/
我试过mysqlcheck -A --自动修复我也一样，但过了一会儿就直流了（比跑步时更容易mysqldump）。
有任何想法吗？
编辑：
尝试转储某个表“bandeira”时丢失连接：
2073 Query SET SESSION character_set_results = 'binary'
2073 Query use `ct1222`
2073 Query select @@collation_database
2073 Query SHOW TRIGGERS LIKE 'baixa\_prod'
2073 Query SET SESSION character_set_results = 'utf8'
2073 Query show table status like 'bandeira'
2073 Query SET OPTION SQL_QUOTE_SHOW_CREATE=1
2073 Query SET SESSION character_set_results = 'binary'
2073 Query show create table `bandeira`
2073 Query SET SESSION character_set_results = 'utf8'
2073 Query show fields from `bandeira`
2073 Query SELECT /*!40001 SQL_NO_CACHE */ * FROM `bandeira`
我跑了mysql检查它说没问题：
# mysqlcheck ct1222 bandeira
ct1222.bandeira OK
mysql_错误.log：
InnoDB: Error: tried to read 16384 bytes at offset 0 7290880.
InnoDB: Was only able to read -1.
180829 17:49:36 InnoDB: Operating system error number 5 in a file operation.
InnoDB: Error number 5 means 'Input/output error'.
InnoDB: Some operating system error numbers are described at
InnoDB: http://dev.mysql.com/doc/refman/5.1/en/operating-system-error-codes.html
InnoDB: File operation call: 'read'.
InnoDB: Cannot continue operation.
180829 17:49:38 mysqld_safe Number of processes running now: 0
180829 17:49:38 mysqld_safe mysqld restarted
180829 17:49:38 [Warning] 'for replication startup options' is deprecated and will be removed in a future release. Please use ''CHANGE MASTER'' instead.
180829 17:49:38 [Note] Plugin 'FEDERATED' is disabled.
180829 17:49:38 InnoDB: Initializing buffer pool, size = 8.0M
180829 17:49:38 InnoDB: Completed initialization of buffer pool
InnoDB: The log sequence number in ibdata files does not match
InnoDB: the log sequence number in the ib_logfiles!
180829 17:49:38 InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
180829 17:49:41 InnoDB: Started; log sequence number
答案1
您的硬件似乎出现了问题。
具体来说，这似乎是硬盘故障。当 InnoDB 尝试从磁盘读取页面时，由于不可恢复的 I/O 错误而无法读取。这是致命的，因此服务器实际上会停止、崩溃，这就是您失去连接的原因。
之后，mysqld_safe Number of processes running now: 0MySQL 会自行重新启动并从错误中恢复——因此实际错误高于该线（换句话说，不要对接下来发生的事情感到惊慌或分心。）
我猜测您没有备份，因为创建备份会遇到同样的错误。
但这似乎并不是“MySQL 问题”。您应该发现您也无法将 MySQL 的文件复制到另一个磁盘，因为复制受影响的文件会遇到相同的错误。具体哪个文件取决于 的设置innodb_file_per_table。如果设置为 ，0那么恢复将变得更加复杂。