以前就用过自己搭建MySQL服务器的两种存储引擎MyISAM和InnoDB(也用过一点Memory方式),在今年初转向阿里云关系型数据库服务RDS的时候,看到可调参数中有一个TokuDB,不过不太了解也没有管。

  最近同事转给我阿里云介绍TokuDB的文章,其中压缩存储的特性对我们来说很有吸引力,因为我们的数据库一般都偏大,已经转到阿里云的就有几百个GB了,加上以后要转的肯定是TB数量级的,而且目前还是用的MyISAM,如果用InnoDB的话,那还要扩大数倍,仅仅是存储的费用就让人难以承受。但MyISAM存在表容易损坏的问题,往后用的人越来越少,Drupal 7 以后默认的支持引擎都改为InnoDB,阿里云也推荐不要使用MyISAM。

  据说这个TokuDB与InnoDB的特性很类似,而改用压缩方式后特别适合大数据时代的应用,但数据的压缩解压必定带来CPU在这方面的消耗,这不是大的问题,我关注的主要是IOPS和连接数是否会增加,如果这两个参数基本维持稳定的话,用CPU来换存储空间还是值得的、有余地的。

  虽然今天是周末,但也还是找了几篇文章、网站查看:

  然后马上就把我博客所在的RDS中多数表都从InnoDB改为TokuDB了,这个RDS的空间从1.8G下降到约800M,下降了一多半,还是很明显的,如果是更大数据量的表下降应该更加明显,不过如果以前是MyISAM的话,下降可能就不那么明显了。

  另外,要设置loose_tokudb_buffer_pool_ratio为合适的比例,也就是tokudb占用tokudb与innodb共用缓存的比例,默认在tokudb不使用的情况下是0,如果全部都用tokudb可以改为100,也可以在innodb转换tokudb前根据下面公式来计算:

select sum(data_length) into @all_size from information_schema.tables where engine='innodb';
select sum(data_length) into @change_size from information_schema.tables where engine='innodb' and concat(table_schema, '.', table_name) in ('XX.XXXX', 'XX.XXXX', 'XX.XXXX');
select round(@change_size/@all_size*100);

  或者转换后根据我自己改写的公式来计算:

select sum(data_length) into @innodb_size from information_schema.tables where engine='innodb';
select sum(data_length) into @tokudb_size from information_schema.tables where engine='tokudb';
select round(@tokudb_size/(@innodb_size+@tokudb_size)*100);

  改变后各种参数还在观察中,如果效果好再推广到其他RDS的其他数据上。


  参考与tokudb有关的变量:

mysql>show variables like '%tokudb%';
+---------------------------------+-----------------+
| Variable_name | Value |
+---------------------------------+-----------------+
| tokudb_alter_print_error | OFF |
| tokudb_analyze_delete_fraction | 1.000000 |
| tokudb_analyze_time | 5 |
| tokudb_block_size | 4194304 |
| tokudb_bulk_fetch | ON |
| tokudb_cache_size | 905969664 |
| tokudb_check_jemalloc | 1 |
| tokudb_checkpoint_lock | OFF |
| tokudb_checkpoint_on_flush_logs | OFF |
| tokudb_checkpointing_period | 60 |
| tokudb_cleaner_iterations | 5 |
| tokudb_cleaner_period | 1 |
| tokudb_commit_sync | ON |
| tokudb_cpu_nums | 0 |
| tokudb_create_index_online | ON |
| tokudb_data_dir | |
| tokudb_debug | 0 |
| tokudb_directio | OFF |
| tokudb_disable_hot_alter | OFF |
| tokudb_disable_prefetching | OFF |
| tokudb_disable_slow_alter | OFF |
| tokudb_disable_slow_update | OFF |
| tokudb_disable_slow_upsert | OFF |
| tokudb_empty_scan | rl |
| tokudb_fs_reserve_percent | 5 |
| tokudb_fsync_log_period | 0 |
| tokudb_hide_default_row_format | ON |
| tokudb_killed_time | 4000 |
| tokudb_last_lock_timeout | |
| tokudb_load_save_space | ON |
| tokudb_loader_memory_size | 100000000 |
| tokudb_lock_timeout | 4000 |
| tokudb_lock_timeout_debug | 1 |
| tokudb_log_dir | |
| tokudb_max_lock_memory | 113246208 |
| tokudb_optimize_index_fraction | 1.000000 |
| tokudb_optimize_index_name | |
| tokudb_optimize_throttle | 0 |
| tokudb_pk_insert_mode | 1 |
| tokudb_prelock_empty | ON |
| tokudb_read_block_size | 65536 |
| tokudb_read_buf_size | 131072 |
| tokudb_read_status_frequency | 10000 |
| tokudb_row_format | tokudb_zlib |
| tokudb_rpl_check_readonly | ON |
| tokudb_rpl_lookup_rows | ON |
| tokudb_rpl_lookup_rows_delay | 0 |
| tokudb_rpl_unique_checks | ON |
| tokudb_rpl_unique_checks_delay | 0 |
| tokudb_support_xa | ON |
| tokudb_tmp_dir | |
| tokudb_version | 7.5.6 |
| tokudb_write_status_frequency | 1000 |
+---------------------------------+-----------------+
共返回 53 行记录,花费 117.83 ms.

  查看与tokedb有关的状态:

mysql>show status like '%tokudb%';
+-----------------------------------------------------------------+--------------------------+
| Variable_name | Value |
+-----------------------------------------------------------------+--------------------------+
| Tokudb_DB_OPENS | 1074 |
| Tokudb_DB_CLOSES | 17 |
| Tokudb_DB_OPEN_CURRENT | 1057 |
| Tokudb_DB_OPEN_MAX | 1057 |
| Tokudb_CHECKPOINT_PERIOD | 60 |
| Tokudb_CHECKPOINT_LAST_BEGAN | Mon Jul 13 11:22:52 2015 |
| Tokudb_CHECKPOINT_LAST_COMPLETE_BEGAN | Mon Jul 13 11:21:52 2015 |
| Tokudb_CHECKPOINT_LAST_COMPLETE_ENDED | Mon Jul 13 11:22:09 2015 |
| Tokudb_CHECKPOINT_DURATION | 185 |
| Tokudb_CHECKPOINT_DURATION_LAST | 17 |
| Tokudb_CHECKPOINT_TAKEN | 23 |
| Tokudb_CHECKPOINT_FAILED | 0 |
| Tokudb_CHECKPOINT_BEGIN_TIME | 120980 |
| Tokudb_CHECKPOINT_LONG_BEGIN_TIME | 0 |
| Tokudb_CHECKPOINT_LONG_BEGIN_COUNT | 0 |
| Tokudb_CACHETABLE_MISS | 4604 |
| Tokudb_CACHETABLE_MISS_TIME | 4345137 |
| Tokudb_CACHETABLE_PREFETCHES | 10 |
| Tokudb_CACHETABLE_SIZE_CURRENT | 907181668 |
| Tokudb_CACHETABLE_SIZE_LIMIT | 996566630 |
| Tokudb_CACHETABLE_SIZE_WRITING | 0 |
| Tokudb_CACHETABLE_SIZE_NONLEAF | 1818161 |
| Tokudb_CACHETABLE_SIZE_LEAF | 902267903 |
| Tokudb_CACHETABLE_SIZE_ROLLBACK | 832 |
| Tokudb_CACHETABLE_SIZE_CACHEPRESSURE | 760812 |
| Tokudb_CACHETABLE_SIZE_CLONED | 3094772 |
| Tokudb_CACHETABLE_EVICTIONS | 60 |
| Tokudb_CACHETABLE_CLEANER_EXECUTIONS | 2156 |
| Tokudb_CACHETABLE_CLEANER_PERIOD | 1 |
| Tokudb_CACHETABLE_CLEANER_ITERATIONS | 5 |
| Tokudb_CACHETABLE_WAIT_PRESSURE_COUNT | 0 |
| Tokudb_CACHETABLE_WAIT_PRESSURE_TIME | 0 |
| Tokudb_CACHETABLE_LONG_WAIT_PRESSURE_COUNT | 0 |
| Tokudb_CACHETABLE_LONG_WAIT_PRESSURE_TIME | 0 |
| Tokudb_LOCKTREE_MEMORY_SIZE | 0 |
| Tokudb_LOCKTREE_MEMORY_SIZE_LIMIT | 113246208 |
| Tokudb_LOCKTREE_ESCALATION_NUM | 0 |
| Tokudb_LOCKTREE_ESCALATION_SECONDS | 0.000000 |
| Tokudb_LOCKTREE_LATEST_POST_ESCALATION_MEMORY_SIZE | 0 |
| Tokudb_LOCKTREE_OPEN_CURRENT | 1059 |
| Tokudb_LOCKTREE_PENDING_LOCK_REQUESTS | 0 |
| Tokudb_LOCKTREE_STO_ELIGIBLE_NUM | 0 |
| Tokudb_LOCKTREE_STO_ENDED_NUM | 84 |
| Tokudb_LOCKTREE_STO_ENDED_SECONDS | 0.001284 |
| Tokudb_LOCKTREE_WAIT_COUNT | 0 |
| Tokudb_LOCKTREE_WAIT_TIME | 0 |
| Tokudb_LOCKTREE_LONG_WAIT_COUNT | 0 |
| Tokudb_LOCKTREE_LONG_WAIT_TIME | 0 |
| Tokudb_LOCKTREE_TIMEOUT_COUNT | 0 |
| Tokudb_LOCKTREE_WAIT_ESCALATION_COUNT | 0 |
| Tokudb_LOCKTREE_WAIT_ESCALATION_TIME | 0 |
| Tokudb_LOCKTREE_LONG_WAIT_ESCALATION_COUNT | 0 |
| Tokudb_LOCKTREE_LONG_WAIT_ESCALATION_TIME | 0 |
| Tokudb_DICTIONARY_UPDATES | 0 |
| Tokudb_DICTIONARY_BROADCAST_UPDATES | 0 |
| Tokudb_DESCRIPTOR_SET | 0 |
| Tokudb_MESSAGES_IGNORED_BY_LEAF_DUE_TO_MSN | 207 |
| Tokudb_LEAF_NODES_FLUSHED_NOT_CHECKPOINT | 2 |
| Tokudb_LEAF_NODES_FLUSHED_NOT_CHECKPOINT_BYTES | 694272 |
| Tokudb_LEAF_NODES_FLUSHED_NOT_CHECKPOINT_UNCOMPRESSED_BYTES | 5592182 |
| Tokudb_LEAF_NODES_FLUSHED_NOT_CHECKPOINT_SECONDS | 0.637258 |
| Tokudb_NONLEAF_NODES_FLUSHED_TO_DISK_NOT_CHECKPOINT | 0 |
| Tokudb_NONLEAF_NODES_FLUSHED_TO_DISK_NOT_CHECKPOINT_BYTES | 0 |
| Tokudb_NONLEAF_NODES_FLUSHED_TO_DISK_NOT_CHECKPOINT_UNCOMPRESSE | 0 |
| Tokudb_NONLEAF_NODES_FLUSHED_TO_DISK_NOT_CHECKPOINT_SECONDS | 0.000000 |
| Tokudb_LEAF_NODES_FLUSHED_CHECKPOINT | 1155 |
| Tokudb_LEAF_NODES_FLUSHED_CHECKPOINT_BYTES | 273844224 |
| Tokudb_LEAF_NODES_FLUSHED_CHECKPOINT_UNCOMPRESSED_BYTES | 1223284397 |
| Tokudb_LEAF_NODES_FLUSHED_CHECKPOINT_SECONDS | 6.420306 |
| Tokudb_NONLEAF_NODES_FLUSHED_TO_DISK_CHECKPOINT | 506 |
| Tokudb_NONLEAF_NODES_FLUSHED_TO_DISK_CHECKPOINT_BYTES | 484352 |
| Tokudb_NONLEAF_NODES_FLUSHED_TO_DISK_CHECKPOINT_UNCOMPRESSED_BY | 600902 |
| Tokudb_NONLEAF_NODES_FLUSHED_TO_DISK_CHECKPOINT_SECONDS | 0.390991 |
| Tokudb_LEAF_NODE_COMPRESSION_RATIO | 4.476154 |
| Tokudb_NONLEAF_NODE_COMPRESSION_RATIO | 1.240631 |
| Tokudb_OVERALL_NODE_COMPRESSION_RATIO | 4.470456 |
| Tokudb_NONLEAF_NODE_PARTIAL_EVICTIONS | 5839 |
| Tokudb_NONLEAF_NODE_PARTIAL_EVICTIONS_BYTES | 1831390 |
| Tokudb_LEAF_NODE_PARTIAL_EVICTIONS | 135986 |
| Tokudb_LEAF_NODE_PARTIAL_EVICTIONS_BYTES | 12265410353 |
| Tokudb_LEAF_NODE_FULL_EVICTIONS | 56 |
| Tokudb_LEAF_NODE_FULL_EVICTIONS_BYTES | 63468429 |
| Tokudb_NONLEAF_NODE_FULL_EVICTIONS | 4 |
| Tokudb_NONLEAF_NODE_FULL_EVICTIONS_BYTES | 4662 |
| Tokudb_LEAF_NODES_CREATED | 87 |
| Tokudb_NONLEAF_NODES_CREATED | 0 |
| Tokudb_LEAF_NODES_DESTROYED | 0 |
| Tokudb_NONLEAF_NODES_DESTROYED | 0 |
| Tokudb_MESSAGES_INJECTED_AT_ROOT_BYTES | 61828 |
| Tokudb_MESSAGES_FLUSHED_FROM_H1_TO_LEAVES_BYTES | 60424 |
| Tokudb_MESSAGES_IN_TREES_ESTIMATE_BYTES | 1404 |
| Tokudb_MESSAGES_INJECTED_AT_ROOT | 911 |
| Tokudb_BROADCASE_MESSAGES_INJECTED_AT_ROOT | 0 |
| Tokudb_BASEMENTS_DECOMPRESSED_TARGET_QUERY | 51 |
| Tokudb_BASEMENTS_DECOMPRESSED_PRELOCKED_RANGE | 1 |
| Tokudb_BASEMENTS_DECOMPRESSED_PREFETCH | 0 |
| Tokudb_BASEMENTS_DECOMPRESSED_FOR_WRITE | 47 |
| Tokudb_BUFFERS_DECOMPRESSED_TARGET_QUERY | 3167 |
| Tokudb_BUFFERS_DECOMPRESSED_PRELOCKED_RANGE | 45 |
| Tokudb_BUFFERS_DECOMPRESSED_PREFETCH | 0 |
| Tokudb_BUFFERS_DECOMPRESSED_FOR_WRITE | 3428 |
| Tokudb_PIVOTS_FETCHED_FOR_QUERY | 3789 |
| Tokudb_PIVOTS_FETCHED_FOR_QUERY_BYTES | 96169472 |
| Tokudb_PIVOTS_FETCHED_FOR_QUERY_SECONDS | 1.042154 |
| Tokudb_PIVOTS_FETCHED_FOR_PREFETCH | 10 |
| Tokudb_PIVOTS_FETCHED_FOR_PREFETCH_BYTES | 327680 |
| Tokudb_PIVOTS_FETCHED_FOR_PREFETCH_SECONDS | 0.000682 |
| Tokudb_PIVOTS_FETCHED_FOR_WRITE | 118 |
| Tokudb_PIVOTS_FETCHED_FOR_WRITE_BYTES | 1263104 |
| Tokudb_PIVOTS_FETCHED_FOR_WRITE_SECONDS | 0.001498 |
| Tokudb_BASEMENTS_FETCHED_TARGET_QUERY | 126157 |
| Tokudb_BASEMENTS_FETCHED_TARGET_QUERY_BYTES | 1243361280 |
| Tokudb_BASEMENTS_FETCHED_TARGET_QUERY_SECONDS | 3.823805 |
| Tokudb_BASEMENTS_FETCHED_PRELOCKED_RANGE | 4673 |
| Tokudb_BASEMENTS_FETCHED_PRELOCKED_RANGE_BYTES | 40569344 |
| Tokudb_BASEMENTS_FETCHED_PRELOCKED_RANGE_SECONDS | 0.118158 |
| Tokudb_BASEMENTS_FETCHED_PREFETCH | 4345 |
| Tokudb_BASEMENTS_FETCHED_PREFETCH_BYTES | 30583808 |
| Tokudb_BASEMENTS_FETCHED_PREFETCH_SECONDS | 0.045414 |
| Tokudb_BASEMENTS_FETCHED_FOR_WRITE | 11625 |
| Tokudb_BASEMENTS_FETCHED_FOR_WRITE_BYTES | 138430464 |
| Tokudb_BASEMENTS_FETCHED_FOR_WRITE_SECONDS | 0.237772 |
| Tokudb_BUFFERS_FETCHED_TARGET_QUERY | 337 |
| Tokudb_BUFFERS_FETCHED_TARGET_QUERY_BYTES | 182784 |
| Tokudb_BUFFERS_FETCHED_TARGET_QUERY_SECONDS | 0.001289 |
| Tokudb_BUFFERS_FETCHED_PRELOCKED_RANGE | 28 |
| Tokudb_BUFFERS_FETCHED_PRELOCKED_RANGE_BYTES | 14848 |
| Tokudb_BUFFERS_FETCHED_PRELOCKED_RANGE_SECONDS | 0.000033 |
| Tokudb_BUFFERS_FETCHED_PREFETCH | 0 |
| Tokudb_BUFFERS_FETCHED_PREFETCH_BYTES | 0 |
| Tokudb_BUFFERS_FETCHED_PREFETCH_SECONDS | 0.000000 |
| Tokudb_BUFFERS_FETCHED_FOR_WRITE | 902 |
| Tokudb_BUFFERS_FETCHED_FOR_WRITE_BYTES | 487936 |
| Tokudb_BUFFERS_FETCHED_FOR_WRITE_SECONDS | 0.001105 |
| Tokudb_LEAF_COMPRESSION_TO_MEMORY_SECONDS | 117.437031 |
| Tokudb_LEAF_SERIALIZATION_TO_MEMORY_SECONDS | 6.225201 |
| Tokudb_LEAF_DECOMPRESSION_TO_MEMORY_SECONDS | 66.514842 |
| Tokudb_LEAF_DESERIALIZATION_TO_MEMORY_SECONDS | 29.246856 |
| Tokudb_NONLEAF_COMPRESSION_TO_MEMORY_SECONDS | 1.533011 |
| Tokudb_NONLEAF_SERIALIZATION_TO_MEMORY_SECONDS | 0.013500 |
| Tokudb_NONLEAF_DECOMPRESSION_TO_MEMORY_SECONDS | 0.038646 |
| Tokudb_NONLEAF_DESERIALIZATION_TO_MEMORY_SECONDS | 0.048904 |
| Tokudb_PROMOTION_ROOTS_SPLIT | 0 |
| Tokudb_PROMOTION_LEAF_ROOTS_INJECTED_INTO | 2422 |
| Tokudb_PROMOTION_H1_ROOTS_INJECTED_INTO | 369 |
| Tokudb_PROMOTION_INJECTIONS_AT_DEPTH_0 | 97 |
| Tokudb_PROMOTION_INJECTIONS_AT_DEPTH_1 | 1533 |
| Tokudb_PROMOTION_INJECTIONS_AT_DEPTH_2 | 645 |
| Tokudb_PROMOTION_INJECTIONS_AT_DEPTH_3 | 171 |
| Tokudb_PROMOTION_INJECTIONS_LOWER_THAN_DEPTH_3 | 0 |
| Tokudb_PROMOTION_STOPPED_NONEMPTY_BUFFER | 420 |
| Tokudb_PROMOTION_STOPPED_AT_HEIGHT_1 | 83 |
| Tokudb_PROMOTION_STOPPED_CHILD_LOCKED_OR_NOT_IN_MEMORY | 4 |
| Tokudb_PROMOTION_STOPPED_CHILD_NOT_FULLY_IN_MEMORY | 14 |
| Tokudb_PROMOTION_STOPPED_AFTER_LOCKING_CHILD | 10 |
| Tokudb_BASEMENT_DESERIALIZATION_FIXED_KEY | 100372 |
| Tokudb_BASEMENT_DESERIALIZATION_VARIABLE_KEY | 46722 |
| Tokudb_CURSOR_SKIP_DELETED_LEAF_ENTRY | 5454 |
| Tokudb_TXN_BEGIN | 935566 |
| Tokudb_TXN_BEGIN_READ_ONLY | 15290 |
| Tokudb_TXN_COMMITS | 927289 |
| Tokudb_TXN_ABORTS | 23544 |
| Tokudb_LOGGER_WRITES | 1732 |
| Tokudb_LOGGER_WRITES_BYTES | 2942123 |
| Tokudb_LOGGER_WRITES_UNCOMPRESSED_BYTES | 2942123 |
| Tokudb_LOGGER_WRITES_SECONDS | 3.539385 |
| Tokudb_LOGGER_WAIT_LONG | 0 |
| Tokudb_LOADER_NUM_CREATED | 0 |
| Tokudb_LOADER_NUM_CURRENT | 0 |
| Tokudb_LOADER_NUM_MAX | 0 |
| Tokudb_MEM_ESTIMATED_MAXIMUM_MEMORY_FOOTPRINT | 0 |
| Tokudb_FILESYSTEM_THREADS_BLOCKED_BY_FULL_DISK | 0 |
| Tokudb_FILESYSTEM_FSYNC_TIME | 59781155 |
| Tokudb_FILESYSTEM_FSYNC_NUM | 4056 |
| Tokudb_FILESYSTEM_LONG_FSYNC_TIME | 0 |
| Tokudb_FILESYSTEM_LONG_FSYNC_NUM | 0 |
| Tokudb_rows_inserted | 998 |
| Tokudb_rows_read | 62354889 |
| Tokudb_rows_deleted | 169 |
| Tokudb_rows_updated | 1043 |
+-----------------------------------------------------------------+--------------------------+
共返回 180 行记录,花费 189.37 ms.

  一些参数还需要摸索调整。


  2015年7月14日夜补充:前两天看到tokudb的压缩特性很高兴,就连夜转了好几台RDS上的很多库中的表,但这两天RDS接连出现问题,主要是日志中有大量这样的报错:errno: 24 - Too many open files,查阅资料后得知tokudb是每个索引都要建一个文件(innodb/myisam都是按每个表来新建一组文件),那如果表多、索引多,就容易超出RDS打开文件数的限制。阿里云客服后来打来电话,建议:

  1. 把tokudb转回innodb,解决目前的文件数报错问题;
  2. 测试innodb压缩,看能否替换tokudb的压缩功能,并获得合适的性能;
  3. 把myisam也转为innodb压缩格式,避免myisam文件出错问题。

  今天又花了很多时间来做这方面的转换和测试。

试用阿里云RDS的MySQL压缩存储引擎TokuDB的更多相关文章

  1. 阿里云 RDS for MySQL支持什么引擎

    问题:我们的服务器是买的是阿里云,mysql版本5.011 ,本地和服务器配置一样,在本地可以安装discuzX3.4,但是在服务器上却报错了,如下图: 找了半天,才知道阿里云RDS 支持的mysql ...

  2. 为更强大而生的开源关系型数据库来了!阿里云RDS for MySQL 8.0 正式上线!

    2019年5月29日15时,阿里云RDS for MySQL 8.0正式上线,使得阿里云成为紧跟社区步伐,发布MySQL最新版本的云厂商.RDS for MySQL 8.0 产品是阿里云推出的 MyS ...

  3. 阿里云RDS的mysql数据库占用空间超过90%的处理

    阿里云RDS数据库最大支持2T,目前已经占用了90%,如果进行分库或者迁移比较麻烦,思路是找出占用空间过大的日志或不重要的文件进行删除操作 查询所有数据库占用磁盘空间大小的SQL语句: show bi ...

  4. 阿里云RDS for MySQL 快速入门——笔记

    1初始化配置 1.1设置白名单 创建RDS实例后,需要设置RDS实例的白名单,以允许外部设备访问该RDS实例.默认的白名单只包含默认IP地址127.0.0.1,表示任何设备均无法访问该RDS实例. 设 ...

  5. 阿里云 RDS for MySQL 物理备份文件恢复到自建数据库

    想把阿里云的Mysql 生成的RAS 文件.tar文件 恢复到本地自建mysql, 遇到的坑.希望帮助大家 阿里云提供的地址 https://help.aliyun.com/knowledge_det ...

  6. 你需要知道的MySQL开源存储引擎TokuDB

    在四月份的Percona Live MySQL会议上, TokuDB庆祝自己成为开源存储引擎整一周年.我现在仍能记得一年前它刚创建时的官方声明与对它的期望.当时的情况非常有意思,因为它拥有帮助MySQ ...

  7. 阿里云RDS for MySQL备份文件+binlog恢复过程中碰到的一些问题

    1.一开始通过官方下载有的压缩包安装,碰到各种依赖问题,最后采用YUM安装 1.通过yum安装percona-Xtrabackup 1.1 先安装依赖: yum install perl-DBI yu ...

  8. 记阿里云 RDS MySQL 的一个大坑

    花了一个下午的时间,终于把一个阿里云 RDS MySQL 的一个大坑填上了,解决方法令人匪夷所思!绝对会让各位看官感到大吃一惊,阿里云 RDS MySQL 居然有这样 xx 的大坑! 问题 最近应业务 ...

  9. 阿里云RDS数据库改造迁移方案

    1. 改造原因 (1) 由于历史原因, 本应该是同一个库的表分布在两个数据库中,需要对这两个库进行合并. (2) 已有的数据库性能无法满足业务的增长需要, 查询卡,慢问题突出. (3) 当前自建Mys ...

随机推荐

  1. VlanTrunk

    简单的vlan trunk的配置: 第一步:添加vlan 1 Switch>enable 2 Switch#show vlan VLAN Name Status Ports ---- ----- ...

  2. 由RGB到HSV颜色空间的理解

    1. RGB模型 2. HSV模型 3. 如何理解RGB与HSV的联系 4. HSV在图像处理中的应用 5. opencv中RGB-->HSV实现 在图像处理中,最常用的颜色空间是RGB模型,常 ...

  3. SqlDataAdapter.Update批量数据更新

    SqlDataAdapter.Update批量数据更新 使用SqlDataAdapter.Update可以方便地对数据库进行快速.批量数据更新.我们最常用的多条数据更新方法是使用循环多次执行SQL语句 ...

  4. mysql 正确的关闭方式

    ./bin/mysqladmin -uroot -p123456 -S /home/allen/var/mysql/mysql.sock shutdown

  5. 初来乍到--------smarty

    Smarty Day01-----smarty的使用 作用:把php+html分离,程序和美工 使用: 1.下载源码包 2.目录结构 libs 源码文件 Smarty.class.php templa ...

  6. NET Core开发-使用Nancy框架

    NET Core开发-使用Nancy框架 Nancy简介 Nancy是一个轻量级的独立的框架,下面是官网的一些介绍: Nancy 是一个轻量级用于构建基于 HTTP 的 Web 服务,基于 .NET ...

  7. Y5V贴片电容(MLCC)容量范围速查表

    Y5V贴片电容简述 Y5V贴片电容属于EIA规定的Class 2类材料的电容.它的电容量受温度.电压.时间变化影响大. Y5V贴片电容特性 具有较差的电容量稳定性,在-25℃-85℃工作温度范围内,温 ...

  8. Html小插件

    1.天气预报插件 效果图: 源代码: <iframe width="650" scrolling="no" height="60" f ...

  9. MFC 动态创建控件

    动态控件是指在需要时由Create()创建的控件,这与预先在对话框中放置的控件是不同的.   一.创建动态控件:   为了对照,我们先来看一下静态控件的创建.   放置静态控件时必须先建立一个容器,一 ...

  10. linux c in common use function reference manual

    End User License Agreement guarantees or warranties,大战前得磨刀!!!!! Tips:C Funcs Chk header Modules!