mysqldump导数报错error 2008处理办法

mysqldump导出dump文件时收到MySQL客户端从服务器获取数据时内存耗尽的报错。

报错信息：

mysqldump: Out of memory (Needed 2356236304 bytes)
mysqldump: Got error: 2008: MySQL client ran out of memory when retrieving data from server

可能原因：

单次导出的表行数太多，超过了mysql客户端的内存限制（可能是max_allowed_packet参数，默认256M）。

解决办法：

mysqldump命令加上--single-transaction --skip-opt --extended-insert --quick参数。
也可以单独加上--opt参数，但是生产环境不建议，因为会锁表。

如果需要忽略包含特定字符的表，使用多个--ignore-table参数指定。

导出DBNAME库中的所有表，但不包括TABLE_1和TABLE_2：

mysqldump -h127.0.0.1 -P3306 -uroot --set-gtid-purged=OFF \
--single-transaction --skip-opt --add-drop-database --extended-insert --quick \
--ignore-table=DBNAME.TABLE_1 --ignore-table=DBNAME.TABLE_2 \
-B DBNAME > dump_DBNAME_`date +%F`.sql

拼接表名清单：

select group_concat(concat_ws('.',table_schema,table_name) separator ' --ignore-table=') 
as not_need_table_list
from information_schema.tables
where table_schema = 'DBNAME' and table_name like '%2023%'\G

重要参数含义官方解释：

• –opt
  This option, enabled by default, is shorthand for the combination of --add-drop-table --add-locks --create-options --disable-keys --extended-insert --lock-tables --quick --set-charset. It gives a fast dump operation and produces a dump file that can be reloaded into a MySQL server quickly.
  Because the --opt option is enabled by default, you only specify its converse, the --skip-opt to turn off several default settings. See the discussion of mysqldump option groups for information about selectively enabling or disabling a subset of the options affected by --opt.

• –quick
  This option is useful for dumping large tables. It forces mysqldump to retrieve rows for a table from the server a row at a time rather than retrieving the entire row set and buffering it in memory before writing it out.

• –extended-insert
  Write INSERT statements using multiple-row syntax that includes several VALUES lists. This results in a smaller dump file and speeds up inserts when the file is reloaded.

References
[1] https://dba.stackexchange.com/questions/157649/outofmemory-exception-duing-mysqldump
[2] https://dev.mysql.com/doc/refman/8.0/en/mysqldump.html#option_mysqldump_opt
[3] https://mp.weixin.qq.com/s?__biz=MzI2NzM1OTM4OA==&mid=2247496679&idx=1&sn=bc9391542d1b42c64e1d49632c4cf969&chksm=ea82b614ddf53f0225e2f7249f907f46552283bdb1970d5b340fc94ed9a72638044444542811&scene=27