InnoDB插入计数减慢

Question

我连续对mysql innoDB表进行批量插入，每秒插入比减慢。有些行为是-如果关闭数据插入器(java)应用程序，mysql做一些i/o操作一段时间。-添加一些插入，然后关闭mysql服务器，关闭操作持续时间太长。如果启动和停止mysql没有任何插入，启动和停止操作如此之快。-插入速度(在很大程度上)不取决于表中的数据量。如果重新启动mysql服务器，每秒插入与最后一次每秒重新启动插入类似。

我在论坛上读到了一些评论，不要继续添加，有两个插入之间的差距。有意义吗？为什么sql会慢下来？

查询显示像‘inno%’这样的变量，结果在下面

innodb_adaptive_flushing = ON
innodb_adaptive_hash_index = ON
innodb_additional_mem_pool_size = 20971520
innodb_autoextend_increment = 8
innodb_autoinc_lock_mode = 1
innodb_buffer_pool_instances = 1
innodb_buffer_pool_size = 268435456
innodb_change_buffering = all
innodb_checksums = ON
innodb_commit_concurrency = 0
innodb_concurrency_tickets = 500
innodb_data_file_path = ibdata1:50M:autoextend
innodb_data_home_dir = 
innodb_doublewrite = ON
innodb_fast_shutdown = 1
innodb_file_format = Barracuda
innodb_file_format_check = ON
innodb_file_format_max = Antelope
innodb_file_per_table = ON
innodb_flush_log_at_trx_commit = 2
innodb_flush_method = O_DSYNC
innodb_force_recovery = 0
innodb_io_capacity = 200
innodb_lock_wait_timeout = 50
innodb_locks_unsafe_for_binlog = OFF
innodb_log_buffer_size = 8388608
innodb_log_file_size = 268435456
innodb_log_files_in_group = 2
innodb_log_group_home_dir = ./
innodb_max_dirty_pages_pct = 75
innodb_max_purge_lag = 0
innodb_mirrored_log_groups = 1
innodb_old_blocks_pct = 37
innodb_old_blocks_time = 0
innodb_open_files = 300
innodb_purge_batch_size = 20
innodb_purge_threads = 0
innodb_read_ahead_threshold = 56
innodb_read_io_threads = 4
innodb_replication_delay = 0
innodb_rollback_on_timeout = OFF
innodb_spin_wait_delay = 6
innodb_stats_on_metadata = ON
innodb_stats_sample_pages = 8
innodb_strict_mode = ON
innodb_support_xa = ON
innodb_sync_spin_loops = 30
innodb_table_locks = ON
innodb_thread_concurrency = 0
innodb_thread_sleep_delay = 10000
innodb_use_native_aio = OFF
innodb_use_sys_malloc = ON
innodb_version = 1.1.1
innodb_write_io_threads = 4

谢谢

Answer 1

减速原因是插入操作存储在缓存(脏页)上，并定期写入硬盘驱动器.在脏页内存满之前，插入操作是快速的，然后缓存是满的，插入速度瓶颈磁盘被写入(I/O)。您可以在sql下面显示脏页大小“修改后的db页面”。

show engine innodb status

Answer 2

默认情况下，InnoDB在自动提交模式下工作，这意味着每次插入都需要写入磁盘两次。使用扩展插入(a.k.a.(多行插入)和将多个连续插入封装到事务中可以提高性能。