工作台锁定高负载

Question

我们在将数据写入数据库时​​遇到峰值负载问题 这是错误的例子 SQLSTATE[HY000]: General error: 1205 Lock wait timeout exceeded; try restarting transaction SQL: insert intoresponses(participant_id,survey_id,question_id,question_option_id) values (2204017, 188131, 5, 23) 该表相当大，有 450 万行，在高峰期我们每天向其写入大约 150-200 千行。 MySQL 版本是 5.6.39 表使用 InnoDb 引擎

RDS 上的 MySQL 实例配置（亚马逊服务） 实例类 db.t2.xlarge vCPU 4 内存 16 GB

表结构

    id  int(10) unsigned Auto Increment 
    participant_id  int(10) unsigned    
    survey_id   int(10) unsigned    
    question_id int(10) unsigned    
    question_option_id  int(10) unsigned NULL   
    response_answer text NULL   
    created_at  timestamp NULL  
    updated_at  timestamp NULL

索引

    PRIMARY id
    INDEX   participant_id
    INDEX   survey_id
    INDEX   question_id
    INDEX   question_option_id

外键

    participant_id -> participants(id)
    question_id -> questions(id)
    question_option_id -> question_options(id)
    survey_id -> surveys(id)

InnoDB 设置

innodb_adaptive_flushing    ON
innodb_adaptive_flushing_lwm    10
innodb_adaptive_hash_index  ON
innodb_adaptive_max_sleep_delay 150000
innodb_additional_mem_pool_size 8388608
innodb_api_bk_commit_interval   5
innodb_api_disable_rowlock  OFF
innodb_api_enable_binlog    OFF
innodb_api_enable_mdl   OFF
innodb_api_trx_level    0
innodb_autoextend_increment 64
innodb_autoinc_lock_mode    1
innodb_buffer_pool_dump_at_shutdown OFF
innodb_buffer_pool_dump_now OFF
innodb_buffer_pool_filename ib_buffer_pool
innodb_buffer_pool_instances    8
innodb_buffer_pool_load_abort   OFF
innodb_buffer_pool_load_at_startup  OFF
innodb_buffer_pool_load_now OFF
innodb_buffer_pool_size 12465471488
innodb_change_buffer_max_size   25
innodb_change_buffering all
innodb_checksum_algorithm   innodb
innodb_checksums    ON
innodb_cmp_per_index_enabled    OFF
innodb_commit_concurrency   0
innodb_compression_failure_threshold_pct    5
innodb_compression_level    6
innodb_compression_pad_pct_max  50
innodb_concurrency_tickets  5000
innodb_data_file_path   ibdata1:12M:autoextend
innodb_data_home_dir    /rdsdbdata/db/innodb
innodb_disable_sort_file_cache  OFF
innodb_doublewrite  ON
innodb_fast_shutdown    1
innodb_file_format  Antelope
innodb_file_format_check    ON
innodb_file_format_max  Antelope
innodb_file_per_table   ON
innodb_flush_log_at_timeout 1
innodb_flush_log_at_trx_commit  1
innodb_flush_method O_DIRECT
innodb_flush_neighbors  1
innodb_flushing_avg_loops   30
innodb_force_load_corrupted OFF
innodb_force_recovery   0
innodb_ft_aux_table 
innodb_ft_cache_size    8000000
innodb_ft_enable_diag_print OFF
innodb_ft_enable_stopword   ON
innodb_ft_max_token_size    84
innodb_ft_min_token_size    3
innodb_ft_num_word_optimize 2000
innodb_ft_result_cache_limit    2000000000
innodb_ft_server_stopword_table 
innodb_ft_sort_pll_degree   2
innodb_ft_total_cache_size  640000000
innodb_ft_user_stopword_table   
innodb_io_capacity  200
innodb_io_capacity_max  2000
innodb_large_prefix OFF
innodb_lock_wait_timeout    50
innodb_locks_unsafe_for_binlog  OFF
innodb_log_buffer_size  8388608
innodb_log_compressed_pages ON
innodb_log_file_size    134217728
innodb_log_files_in_group   2
innodb_log_group_home_dir   /rdsdbdata/log/innodb
innodb_lru_scan_depth   1024
innodb_max_dirty_pages_pct  75
innodb_max_dirty_pages_pct_lwm  0
innodb_max_purge_lag    0
innodb_max_purge_lag_delay  0
innodb_mirrored_log_groups  1
innodb_monitor_disable  
innodb_monitor_enable   
innodb_monitor_reset    
innodb_monitor_reset_all    
innodb_numa_interleave  OFF
innodb_old_blocks_pct   37
innodb_old_blocks_time  1000
innodb_online_alter_log_max_size    134217728
innodb_open_files   2000
innodb_optimize_fulltext_only   OFF
innodb_page_size    16384
innodb_print_all_deadlocks  OFF
innodb_purge_batch_size 300
innodb_purge_threads    1
innodb_random_read_ahead    OFF
innodb_read_ahead_threshold 56
innodb_read_io_threads  4
innodb_read_only    OFF
innodb_replication_delay    0
innodb_rollback_on_timeout  OFF
innodb_rollback_segments    128
innodb_sort_buffer_size 1048576
innodb_spin_wait_delay  6
innodb_stats_auto_recalc    ON
innodb_stats_include_delete_marked  OFF
innodb_stats_method nulls_equal
innodb_stats_on_metadata    OFF
innodb_stats_persistent ON
innodb_stats_persistent_sample_pages    20
innodb_stats_sample_pages   8
innodb_stats_transient_sample_pages 8
innodb_status_output    OFF
innodb_status_output_locks  OFF
innodb_strict_mode  OFF
innodb_support_xa   ON
innodb_sync_array_size  1
innodb_sync_spin_loops  30
innodb_table_locks  ON
innodb_thread_concurrency   0
innodb_thread_sleep_delay   10000
innodb_tmpdir   
innodb_undo_directory   .
innodb_undo_logs    128
innodb_undo_tablespaces 0
innodb_use_native_aio   ON
innodb_use_sys_malloc   ON
innodb_version  5.6.39
innodb_write_io_threads 4

Answer 1

我认为将目标和最大 IOPS 提高到默认值之上以避免过度的 SSD 磨损也禁用主动刷新页面可能会有所帮助

innodb_adaptive_flushing_lwm = 0  
Innodb_flush_neighbors = off
innodb_io_capacity=1000
innodb_io_capacity_max=2500

参考：

https://www.percona.com/blog/2019/12/18/give-love-to-your-ssds-reduce-innodb_io_capacity_max/