我有一个名为“tweets”的 5GB MySQL 数据库,我需要从中访问“searchresults”表。但是当我对其执行查询或创建转储时,MySQL 服务器(在 Windows 10 上运行)始终崩溃,并在同一行出现相同的错误。
例如,如果我尝试使用以下命令转储数据库:
C:\xampp\mysql\bin>mysqldump.exe --user root --force tweets > D:\secondtry.sql
我在 cmd.exe 窗口中一遍又一遍地收到以下错误消息,其中包含完全相同的行:
mysqldump.exe: Error 2013: Lost connection to MySQL server during query when dumping table `searchresults` at row: 5222907
mysqldump.exe: Couldn't execute 'SELECT engine FROM INFORMATION_SCHEMA.TABLES WHERE table_name = 'stats'': MySQL server has gone away (2006)
mysqldump.exe: Couldn't execute 'SET SQL_QUOTE_SHOW_CREATE=1': MySQL server has gone away (2006)
mysqldump.exe: Couldn't execute 'SELECT `COLUMN_NAME` AS `Field`, `COLUMN_TYPE` AS `Type`, `IS_NULLABLE` AS `Null`, `COLUMN_KEY` AS `Key`, `COLUMN_DEFAULT` AS `Default`, `EXTRA` AS `Extra`, `COLUMN_COMMENT` AS `Comment` FROM `INFORMATION_SCHEMA`.`COLUMNS` WHERE TABLE_SCHEMA = 'tweets' AND TABLE_NAME = 'stats'': MySQL server has gone away (2006)
mysqldump.exe: Couldn't execute 'UNLOCK TABLES': MySQL server has gone away (2006)
在 mysql_error.log 中,我收到以下消息并且服务器关闭:
Server version: 10.1.8-MariaDB <br/> key_buffer_size=16777216 <br/> read_buffer_size=262144 <br/> max_used_connections=1 <br/> max_threads=1001 <br/> thread_count=1 <br/> It is possible that mysqld could use up to <br/> key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = <br/> 787099 K bytes of memory Hope that's ok; if not, decrease some <br/> variables in the equation.
Thread pointer: 0x0x5b93168 <br/> Attempting backtrace. You can use the <br/> following information to find out where mysqld died. If you see no <br/> messages after this, something went terribly wrong... <br/> mysqld.exe!my_parameter_handler() <br/> mysqld.exe!my_mb_ctype_mb()<br/> mysqld.exe!??0Global_read_lock@@QAE@XZ()<br/> mysqld.exe!??0Global_read_lock@@QAE@XZ()<br/> mysqld.exe!?store_record_for_lookup@Stat_table@@IAEXXZ()<br/> mysqld.exe!??0Global_read_lock@@QAE@XZ()<br/> mysqld.exe!??0Global_read_lock@@QAE@XZ()<br/> mysqld.exe!??0Global_read_lock@@QAE@XZ()<br/> mysqld.exe!?store_record_for_lookup@Stat_table@@IAEXXZ()<br/> mysqld.exe!?store_record_for_lookup@Stat_table@@IAEXXZ()<br/> mysqld.exe!?ha_rnd_next@handler@@QAEHPAE@Z()<br/> mysqld.exe!?rr_sequential@@YAHPAUREAD_RECORD@@@Z()<br/> mysqld.exe!?sub_select@@YA? AW4enum_nested_loop_state@@PAVJOIN@@PAUst_join_table@@_N@Z() <br/> mysqld.exe!?setup_end_select_func@@YAP6A?AW4enum_nested_loop_state@@PAVJOIN@@PAUst_join_table@@_N@Z0@Z() <br/> mysqld.exe!?exec_inner@JOIN@@QAEXXZ() <br/> mysqld.exe!?exec@JOIN@@QAEXXZ()<br/> mysqld.exe!?handle_select@@YA_NPAVTHD@@PAULEX@@PAVselect_result@@K@Z()<br/> mysqld.exe!??0Table_scope_and_contents_source_st@@QAE@ABU0@@Z()<br/> mysqld.exe!?mysql_execute_command@@YAHPAVTHD@@@Z()<br/> mysqld.exe!?mysql_parse@@YAXPAVTHD@@PADIPAVParser_state@@@Z()<br/> mysqld.exe!?dispatch_command@@YA_NW4enum_server_command@@PAVTHD@@PADI@Z()<br/> mysqld.exe!?do_command@@YA_NPAVTHD@@@Z()<br/> mysqld.exe!?threadpool_process_request@@YAHPAVTHD@@@Z()<br/> mysqld.exe!?tp_end@@YAXXZ() <br/> KERNEL32.DLL!SetUserGeoID()<br/> ntdll.dll!TpSimpleTryPost() <br/> ntdll.dll!EtwNotificationRegister()<br/> KERNEL32.DLL!BaseThreadInitThunk()<br/> ntdll.dll!RtlUnicodeStringToInteger()<br/> ntdll.dll!RtlUnicodeStringToInteger()<br/>
Trying to get some variables. Some pointers may be invalid and cause<br/> the dump to abort. Query (0x5b9a908): SELECT /*!40001 SQL_NO_CACHE */<br/>
* FROM `searchresults` <br/> Connection ID (thread ID): 2 <br/> Status: NOT_KILLED<br/>
到目前为止我已经尝试过:
我非常确定第 5222907 或 5222908 行中存在损坏的数据集,这就是服务器崩溃的原因。如果我之后可以访问其余数据,那么丢失一行对我来说完全没问题。我什至可能会丢失前 5222908 行。但是当我无法删除损坏的数据时。如果我使用查询
DELETE FROM searchresults LIMIT 5222908
服务器又崩溃了。
我将非常感谢有关此事的任何提示。这些数据对我来说非常重要,因为我的硕士论文需要它,该论文即将到期。
感谢您的时间和精力!
编辑:这是我的表结构(注意,没有键或索引):
CREATE TABLE `searchresults` (
`id` bigint(20) DEFAULT NULL,
`user` varchar(50) CHARACTER SET latin1 DEFAULT NULL,
`createdAt` timestamp NULL DEFAULT NULL,
`retweetcount` int(11) DEFAULT NULL,
`favoritecount` int(11) DEFAULT NULL,
`message` varchar(500) CHARACTER SET latin1 DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_german1_ci
编辑:我使用了这样的插入:
SELECT id INTO OUTFILE 'C:/Temp/allCount.csv' FIELDS TERMINATED BY ','
OPTIONALLY ENCLOSED BY '"' LINES TERMINATED BY '\n' FROM searchresults;
根据我选择的列(id、转发计数等),我会得到不同数量的行。它们始终低于 5222907,但这意味着问题仍然可能与参数相关,而不是损坏错误。你怎么认为?你知道我可以在 mysql 配置中调整一些额外的参数吗?
您可以考虑修改 mysql 服务器的这些属性:
nano /etc/mysql/my.cnf
query_cache_size=16M
key_buffer_size=256M
或者甚至尝试增加 mysql 客户端查询允许的执行时间:
SET GLOBAL MAX_STATEMENT_TIME=1000;
在执行查询之前。