mysql 查询速度的问题

Question

我管理的网站比较大,后台用的是MYSQL,目前已经有6GB数据了,每次重启 TOMCAT 后MYSQL查询速度速度非常慢,一个查询会等上10多分钟,但是过了一段时间就快了!不知道是为什么?还有,网站会时不时地打不开,我想应该与MYSQL有关,但不知道查看相关MYSQL性能指标,希望哪位前辈能给小弟指点一下,先谢谢了!

Answer 1

贴出你的show status 结果

Answer 2

这是正常情况下的show status:数据(D):
Variable_name Value
Aborted_clients 0
Aborted_connects 0
Binlog_cache_disk_use 7
Binlog_cache_use 4952
Bytes_received 1968
Bytes_sent 175908
Com_admin_commands 0
Com_alter_db 0
Com_alter_table 0
Com_analyze 0
Com_backup_table 0
Com_begin 0
Com_change_db 0
Com_change_master 0
Com_check 0
Com_checksum 0
Com_commit 0
Com_create_db 0
Com_create_function 0
Com_create_index 0
Com_create_table 0
Com_dealloc_sql 0
Com_delete 0
Com_delete_multi 0
Com_do 0
Com_drop_db 0
Com_drop_function 0
Com_drop_index 0
Com_drop_table 0
Com_drop_user 0
Com_execute_sql 0
Com_flush 0
Com_grant 0
Com_ha_close 0
Com_ha_open 0
Com_ha_read 0
Com_help 0
Com_insert 0
Com_insert_select 0
Com_kill 0
Com_load 0
Com_load_master_data 0
Com_load_master_table 0
Com_lock_tables 0
Com_optimize 0
Com_preload_keys 0
Com_prepare_sql 0
Com_purge 0
Com_purge_before_date 0
Com_rename_table 0
Com_repair 0
Com_replace 0
Com_replace_select 0
Com_reset 0
Com_restore_table 0
Com_revoke 0
Com_revoke_all 0
Com_rollback 0
Com_savepoint 0
Com_select 3
Com_set_option 0
Com_show_binlog_events 0
Com_show_binlogs 0
Com_show_charsets 1
Com_show_collations 1
Com_show_column_types 0
Com_show_create_db 0
Com_show_create_table 0
Com_show_databases 0
Com_show_errors 0
Com_show_fields 0
Com_show_grants 0
Com_show_innodb_status 0
Com_show_keys 0
Com_show_logs 0
Com_show_master_status 0
Com_show_ndb_status 0
Com_show_new_master 0
Com_show_open_tables 0
Com_show_privileges 0
Com_show_processlist 1
Com_show_slave_hosts 0
Com_show_slave_status 0
Com_show_status 65
Com_show_storage_engines 0
Com_show_tables 0
Com_show_triggers 0
Com_show_variables 1
Com_show_warnings 0
Com_slave_start 0
Com_slave_stop 0
Com_stmt_close 0
Com_stmt_execute 0
Com_stmt_fetch 0
Com_stmt_prepare 0
Com_stmt_reset 0
Com_stmt_send_long_data 0
Com_truncate 0
Com_unlock_tables 0
Com_update 0
Com_update_multi 0
Com_xa_commit 0
Com_xa_end 0
Com_xa_prepare 0
Com_xa_recover 0
Com_xa_rollback 0
Com_xa_start 0
Compression ON
Connections 384
Created_tmp_disk_tables 0
Created_tmp_files 13
Created_tmp_tables 69
Delayed_errors 0
Delayed_insert_threads 0
Delayed_writes 0
Flush_commands 1
Handler_commit 0
Handler_delete 0
Handler_discover 0
Handler_prepare 0
Handler_read_first 0
Handler_read_key 0
Handler_read_next 0
Handler_read_prev 0
Handler_read_rnd 0
Handler_read_rnd_next 14615
Handler_rollback 0
Handler_savepoint 0
Handler_savepoint_rollback 0
Handler_update 0
Handler_write 14677
Innodb_buffer_pool_pages_data 45897
Innodb_buffer_pool_pages_dirty 18
Innodb_buffer_pool_pages_flushed 13818
Innodb_buffer_pool_pages_free 0
Innodb_buffer_pool_pages_latched 0
Innodb_buffer_pool_pages_misc 183
Innodb_buffer_pool_pages_total 46080
Innodb_buffer_pool_read_ahead_rnd 15731
Innodb_buffer_pool_read_ahead_seq 199
Innodb_buffer_pool_read_requests 18360430
Innodb_buffer_pool_reads 742923
Innodb_buffer_pool_wait_free 0
Innodb_buffer_pool_write_requests 51198
Innodb_data_fsyncs 14018
Innodb_data_pending_fsyncs 0
Innodb_data_pending_reads 0
Innodb_data_pending_writes 0
Innodb_data_read 1333579776
Innodb_data_reads 869264
Innodb_data_writes 25328
Innodb_data_written 463208448
Innodb_dblwr_pages_written 13818
Innodb_dblwr_writes 1046
Innodb_log_waits 0
Innodb_log_write_requests 8783
Innodb_log_writes 11083
Innodb_os_log_fsyncs 11932
Innodb_os_log_pending_fsyncs 0
Innodb_os_log_pending_writes 0
Innodb_os_log_written 9985536
Innodb_page_size 16384
Innodb_pages_created 110
Innodb_pages_read 1391854
Innodb_pages_written 13818
Innodb_row_lock_current_waits 0
Innodb_row_lock_time 0
Innodb_row_lock_time_avg 0
Innodb_row_lock_time_max 0
Innodb_row_lock_waits 1
Innodb_rows_deleted 68
Innodb_rows_inserted 232
Innodb_rows_read 56751532
Innodb_rows_updated 4620
Key_blocks_not_flushed 0
Key_blocks_unused 348900
Key_blocks_used 0
Key_read_requests 0
Key_reads 0
Key_write_requests 0
Key_writes 0
Last_query_cost 10.499000
Max_used_connections 360
Not_flushed_delayed_rows 0
Open_files 20
Open_streams 0
Open_tables 58
Opened_tables 0
Qcache_free_blocks 2007
Qcache_free_memory 19321520
Qcache_hits 24875
Qcache_inserts 18459
Qcache_lowmem_prunes 0
Qcache_not_cached 202516
Qcache_queries_in_cache 7302
Qcache_total_blocks 16639
Questions 633265
Rpl_status NULL
Select_full_join 0
Select_full_range_join 0
Select_range 0
Select_range_check 0
Select_scan 69
Slave_open_temp_tables 0
Slave_retried_transactions 0
Slave_running OFF
Slow_launch_threads 0
Slow_queries 0
Sort_merge_passes 0
Sort_range 0
Sort_rows 0
Sort_scan 0
Table_locks_immediate 197876
Table_locks_waited 0
Tc_log_max_pages_used 0
Tc_log_page_size 0
Tc_log_page_waits 0
Threads_cached 0
Threads_connected 360
Threads_created 369
Threads_running 1
Uptime 8391

Answer 3

这是非正常的(速度极慢):
show status;数据(D):
Variable_name Value
Aborted_clients 734
Aborted_connects 0
Binlog_cache_disk_use 17
Binlog_cache_use 8829
Bytes_received 4221
Bytes_sent 260965
Com_admin_commands 0
Com_alter_db 0
Com_alter_table 0
Com_analyze 0
Com_backup_table 0
Com_begin 0
Com_change_db 0
Com_change_master 0
Com_check 0
Com_checksum 0
Com_commit 0
Com_create_db 0
Com_create_function 0
Com_create_index 0
Com_create_table 0
Com_dealloc_sql 0
Com_delete 0
Com_delete_multi 0
Com_do 0
Com_drop_db 0
Com_drop_function 0
Com_drop_index 0
Com_drop_table 0
Com_drop_user 0
Com_execute_sql 0
Com_flush 0
Com_grant 0
Com_ha_close 0
Com_ha_open 0
Com_ha_read 0
Com_help 0
Com_insert 0
Com_insert_select 0
Com_kill 0
Com_load 0
Com_load_master_data 0
Com_load_master_table 0
Com_lock_tables 0
Com_optimize 0
Com_preload_keys 0
Com_prepare_sql 0
Com_purge 0
Com_purge_before_date 0
Com_rename_table 0
Com_repair 0
Com_replace 0
Com_replace_select 0
Com_reset 0
Com_restore_table 0
Com_revoke 0
Com_revoke_all 0
Com_rollback 0
Com_savepoint 0
Com_select 21
Com_set_option 0
Com_show_binlog_events 0
Com_show_binlogs 0
Com_show_charsets 1
Com_show_collations 1
Com_show_column_types 0
Com_show_create_db 0
Com_show_create_table 0
Com_show_databases 0
Com_show_errors 0
Com_show_fields 0
Com_show_grants 0
Com_show_innodb_status 0
Com_show_keys 0
Com_show_logs 0
Com_show_master_status 0
Com_show_ndb_status 0
Com_show_new_master 0
Com_show_open_tables 0
Com_show_privileges 0
Com_show_processlist 1
Com_show_slave_hosts 0
Com_show_slave_status 0
Com_show_status 90
Com_show_storage_engines 1
Com_show_tables 0
Com_show_triggers 0
Com_show_variables 1
Com_show_warnings 0
Com_slave_start 0
Com_slave_stop 0
Com_stmt_close 0
Com_stmt_execute 0
Com_stmt_fetch 0
Com_stmt_prepare 0
Com_stmt_reset 0
Com_stmt_send_long_data 0
Com_truncate 0
Com_unlock_tables 0
Com_update 0
Com_update_multi 0
Com_xa_commit 0
Com_xa_end 0
Com_xa_prepare 0
Com_xa_recover 0
Com_xa_rollback 0
Com_xa_start 0
Compression ON
Connections 1139
Created_tmp_disk_tables 34
Created_tmp_files 24
Created_tmp_tables 205
Delayed_errors 0
Delayed_insert_threads 0
Delayed_writes 0
Flush_commands 1
Handler_commit 0
Handler_delete 0
Handler_discover 0
Handler_prepare 0
Handler_read_first 7
Handler_read_key 0
Handler_read_next 0
Handler_read_prev 0
Handler_read_rnd 0
Handler_read_rnd_next 20325
Handler_rollback 0
Handler_savepoint 0
Handler_savepoint_rollback 0
Handler_update 0
Handler_write 20336
Innodb_buffer_pool_pages_data 45916
Innodb_buffer_pool_pages_dirty 14
Innodb_buffer_pool_pages_flushed 22353
Innodb_buffer_pool_pages_free 1
Innodb_buffer_pool_pages_latched 12
Innodb_buffer_pool_pages_misc 163
Innodb_buffer_pool_pages_total 46080
Innodb_buffer_pool_read_ahead_rnd 34921
Innodb_buffer_pool_read_ahead_seq 428
Innodb_buffer_pool_read_requests 44126605
Innodb_buffer_pool_reads 1482742
Innodb_buffer_pool_wait_free 0
Innodb_buffer_pool_write_requests 90236
Innodb_data_fsyncs 24322
Innodb_data_pending_fsyncs 0
Innodb_data_pending_reads 3
Innodb_data_pending_writes 0
Innodb_data_read 3921825792
Innodb_data_reads 1752467
Innodb_data_writes 42626
Innodb_data_written 751406080
Innodb_dblwr_pages_written 22353
Innodb_dblwr_writes 1674
Innodb_log_waits 0
Innodb_log_write_requests 16664
Innodb_log_writes 19574
Innodb_os_log_fsyncs 21011
Innodb_os_log_pending_fsyncs 0
Innodb_os_log_pending_writes 0
Innodb_os_log_written 18222080
Innodb_page_size 16384
Innodb_pages_created 244
Innodb_pages_read 2860545
Innodb_pages_written 22353
Innodb_row_lock_current_waits 0
Innodb_row_lock_time 4516
Innodb_row_lock_time_avg 903
Innodb_row_lock_time_max 2955
Innodb_row_lock_waits 5
Innodb_rows_deleted 71
Innodb_rows_inserted 451
Innodb_rows_read 146063971
Innodb_rows_updated 8198
Key_blocks_not_flushed 0
Key_blocks_unused 348900
Key_blocks_used 0
Key_read_requests 0
Key_reads 0
Key_write_requests 0
Key_writes 0
Last_query_cost 0.000000
Max_used_connections 624
Not_flushed_delayed_rows 0
Open_files 78
Open_streams 0
Open_tables 399
Opened_tables 2
Qcache_free_blocks 1611
Qcache_free_memory 29055880
Qcache_hits 40090
Qcache_inserts 33037
Qcache_lowmem_prunes 0
Qcache_not_cached 390837
Qcache_queries_in_cache 2822
Qcache_total_blocks 7276
Questions 1208083
Rpl_status NULL
Select_full_join 0
Select_full_range_join 0
Select_range 0
Select_range_check 0
Select_scan 110
Slave_open_temp_tables 0
Slave_retried_transactions 0
Slave_running OFF
Slow_launch_threads 0
Slow_queries 1
Sort_merge_passes 0
Sort_range 0
Sort_rows 8
Sort_scan 1
Table_locks_immediate 378759
Table_locks_waited 0
Tc_log_max_pages_used 0
Tc_log_page_size 0
Tc_log_page_waits 0
Threads_cached 0
Threads_connected 624
Threads_created 1028
Threads_running 239
Uptime 14102

Answer 4

Handler_read_rnd_next/Com_select远远大于4000
这个值太大了。
在配置文件里增加read_buffer_size
然后再测试
key_read_requests/key_reads>1000才正常
增加key_buffer_size的值。

Answer 5

谢谢 yueliangdao0608 的指点,我先试试看!