我的 MySql 服务器有问题，导致它一直冻结。当发生这种情况时，我在 phpMyAdmin 中的“显示进程列表”中可以看到用户“未经身份验证的用户”的大量进程，命令为“连接”，状态为“从网络读取”。
数据库使用的是 InnoDB，但我还使用一个运行 MyISAM 的表来执行全文搜索。服务器内存约为 4GB，实际使用量不到 1GB。
我一直在使用 MySql 的慢速查询日志来查找未使用索引的查询。我还认为我需要对服务器变量进行一些更改/调整。我真的需要一些帮助，因此我在这里发布了 SHOW GLOBAL STATUS 和 SHOW GLOBAL VARIABLES，也许您可以给我一些关于如何设置变量的想法？
编辑：我意识到我在数据库连接字符串中使用了pooling=false。我将其更改为默认pooling=true，现在性能似乎好多了。这可能是问题所在吗？
当前显示全球状态：
Aborted_clients 156
Aborted_connects 16
Binlog_cache_disk_use 0
Binlog_cache_use 0
Binlog_stmt_cache_disk_use 0
Binlog_stmt_cache_use 0
Bytes_received 7579352758
Bytes_sent 141001605296
Com_admin_commands 1082
Com_assign_to_keycache 0
Com_alter_db 0
Com_alter_db_upgrade 0
Com_alter_event 0
Com_alter_function 0
Com_alter_procedure 0
Com_alter_server 0
Com_alter_table 0
Com_alter_tablespace 0
Com_analyze 0
Com_begin 48
Com_binlog 0
Com_call_procedure 0
Com_change_db 6598162
Com_change_master 0
Com_check 0
Com_checksum 0
Com_commit 0
Com_create_db 0
Com_create_event 0
Com_create_function 0
Com_create_index 0
Com_create_procedure 0
Com_create_server 0
Com_create_table 0
Com_create_trigger 0
Com_create_udf 0
Com_create_user 0
Com_create_view 0
Com_dealloc_sql 0
Com_delete 142688
Com_delete_multi 0
Com_do 0
Com_drop_db 0
Com_drop_event 0
Com_drop_function 0
Com_drop_index 0
Com_drop_procedure 0
Com_drop_server 0
Com_drop_table 0
Com_drop_trigger 0
Com_drop_user 0
Com_drop_view 0
Com_empty_query 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 1445224
Com_insert_select 920
Com_install_plugin 0
Com_kill 11
Com_load 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_release_savepoint 0
Com_rename_table 0
Com_rename_user 0
Com_repair 0
Com_replace 0
Com_replace_select 0
Com_reset 0
Com_resignal 0
Com_revoke 0
Com_revoke_all 0
Com_rollback 0
Com_rollback_to_savepoint 0
Com_savepoint 0
Com_select 4083099
Com_set_option 13201112
Com_signal 0
Com_show_authors 0
Com_show_binlog_events 0
Com_show_binlogs 21
Com_show_charsets 0
Com_show_collations 6596863
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Com_show_create_proc 0
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Com_show_create_trigger 24
Com_show_databases 18
Variable_name Value
Com_show_engine_logs 0
Com_show_engine_mutex 0
Com_show_engine_status 0
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Com_show_errors 0
Com_show_fields 1247
Com_show_function_status 1
Com_show_grants 2
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Com_show_master_status 3
Com_show_open_tables 0
Com_show_plugins 31
Com_show_privileges 0
Com_show_procedure_status 1
Com_show_processlist 13
Com_show_profile 0
Com_show_profiles 0
Com_show_relaylog_events 0
Com_show_slave_hosts 0
Com_show_slave_status 3
Com_show_status 12
Com_show_storage_engines 0
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Com_show_tables 78
Com_show_triggers 1184
Com_show_variables 6596881
Com_show_warnings 586
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Com_update_multi 8320
Com_xa_commit 0
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Com_xa_recover 0
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Com_xa_start 0
Compression OFF
Connections 6597009
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Delayed_errors 0
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Delayed_writes 0
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Handler_rollback 133
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Handler_update 2718211
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Innodb_buffer_pool_pages_misc 11376
Innodb_buffer_pool_pages_total 65535
Innodb_buffer_pool_read_ahead_rnd 0
Innodb_buffer_pool_read_ahead 680486
Innodb_buffer_pool_read_ahead_evicted 463292
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Innodb_data_reads 6306700
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Innodb_data_written 139541615616
Innodb_dblwr_pages_written 4207643
Innodb_dblwr_writes 73094
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Innodb_log_write_requests 1261730
Innodb_log_writes 1998194
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Variable_name Value
Innodb_os_log_pending_fsyncs 0
Innodb_os_log_pending_writes 0
Innodb_os_log_written 1648348672
Innodb_page_size 16384
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Innodb_row_lock_time 3
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Innodb_rows_read 2489728185
Innodb_rows_updated 1528769
Innodb_truncated_status_writes 0
Key_blocks_not_flushed 0
Key_blocks_unused 13
Key_blocks_used 13
Key_read_requests 734915677
Key_reads 10415027
Key_write_requests 121904
Key_writes 113773
Last_query_cost 0.000000
Max_used_connections 90
Not_flushed_delayed_rows 0
Open_files 0
Open_streams 0
Open_table_definitions 113
Open_tables 4
Opened_files 1266796
Opened_table_definitions 109
Opened_tables 6207864
Performance_schema_cond_classes_lost 0
Performance_schema_cond_instances_lost 0
Performance_schema_file_classes_lost 0
Performance_schema_file_handles_lost 0
Performance_schema_file_instances_lost 0
Performance_schema_locker_lost 0
Performance_schema_mutex_classes_lost 0
Performance_schema_mutex_instances_lost 0
Performance_schema_rwlock_classes_lost 0
Performance_schema_rwlock_instances_lost 0
Performance_schema_table_handles_lost 0
Performance_schema_table_instances_lost 0
Performance_schema_thread_classes_lost 0
Performance_schema_thread_instances_lost 0
Prepared_stmt_count 0
Qcache_free_blocks 680
Qcache_free_memory 1672056
Qcache_hits 1252252
Qcache_inserts 4010949
Qcache_lowmem_prunes 334062
Qcache_not_cached 72286
Qcache_queries_in_cache 1115
Qcache_total_blocks 3259
Queries 47199162
Questions 47183133
Rpl_status AUTH_MASTER
Select_full_join 988
Select_full_range_join 0
Select_range 158563
Select_range_check 0
Select_scan 14053416
Slave_heartbeat_period 0.000
Slave_open_temp_tables 0
Slave_received_heartbeats 0
Slave_retried_transactions 0
Slave_running OFF
Slow_launch_threads 0
Slow_queries 132
Sort_merge_passes 8997
Sort_range 715335
Sort_rows 18485859
Sort_scan 173741
Ssl_accept_renegotiates 0
Ssl_accepts 0
Ssl_callback_cache_hits 0
Ssl_cipher
Ssl_cipher_list
Ssl_client_connects 0
Ssl_connect_renegotiates 0
Ssl_ctx_verify_depth 0
Ssl_ctx_verify_mode 0
Ssl_default_timeout 0
Ssl_finished_accepts 0
Ssl_finished_connects 0
Ssl_session_cache_hits 0
Ssl_session_cache_misses 0
Ssl_session_cache_mode NONE
Ssl_session_cache_overflows 0
Ssl_session_cache_size 0
Ssl_session_cache_timeouts 0
Ssl_sessions_reused 0
Ssl_used_session_cache_entries 0
Ssl_verify_depth 0
Ssl_verify_mode 0
Ssl_version
Table_locks_immediate 10953974
Variable_name Value
Table_locks_waited 1791
Tc_log_max_pages_used 0
Tc_log_page_size 0
Tc_log_page_waits 0
Threads_cached 86
Threads_connected 4
Threads_created 90
Threads_running 1
Uptime 347948
Uptime_since_flush_status 347948
当前显示全局变量：
auto_increment_increment 1
auto_increment_offset 1
autocommit ON
automatic_sp_privileges ON
back_log 50
basedir /usr
big_tables OFF
binlog_cache_size 32768
binlog_direct_non_transactional_updates OFF
binlog_format STATEMENT
binlog_stmt_cache_size 32768
bulk_insert_buffer_size 8388608
character_set_client latin1
character_set_connection latin1
character_set_database latin1
character_set_filesystem binary
character_set_results latin1
character_set_server latin1
character_set_system utf8
character_sets_dir /usr/share/mysql/charsets/
collation_connection latin1_swedish_ci
collation_database latin1_swedish_ci
collation_server latin1_swedish_ci
completion_type NO_CHAIN
concurrent_insert AUTO
connect_timeout 10
datadir /var/lib/mysql/
date_format %Y-%m-%d
datetime_format %Y-%m-%d %H:%i:%s
default_storage_engine InnoDB
default_week_format 0
delay_key_write ON
delayed_insert_limit 100
delayed_insert_timeout 300
delayed_queue_size 1000
div_precision_increment 4
engine_condition_pushdown ON
event_scheduler OFF
expire_logs_days 0
flush OFF
flush_time 0
foreign_key_checks ON
ft_boolean_syntax + -><()~*:""&|
ft_max_word_len 84
ft_min_word_len 3
ft_query_expansion_limit 20
ft_stopword_file (built-in)
general_log OFF
general_log_file /var/lib/mysql/db.log
group_concat_max_len 1024
have_compress YES
have_crypt YES
have_csv YES
have_dynamic_loading YES
have_geometry YES
have_innodb YES
have_ndbcluster NO
have_openssl DISABLED
have_partitioning YES
have_profiling YES
have_query_cache YES
have_rtree_keys YES
have_ssl DISABLED
have_symlink YES
hostname silldb5
ignore_builtin_innodb OFF
init_connect
init_file
init_slave
innodb_adaptive_flushing ON
innodb_adaptive_hash_index ON
innodb_additional_mem_pool_size 8388608
innodb_autoextend_increment 8
innodb_autoinc_lock_mode 1
innodb_buffer_pool_instances 1
innodb_buffer_pool_size 1073741824
innodb_change_buffering all
innodb_checksums ON
innodb_commit_concurrency 0
innodb_concurrency_tickets 500
innodb_data_file_path ibdata1:10M:autoextend
innodb_data_home_dir
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 OFF
innodb_flush_log_at_trx_commit 1
innodb_flush_method
innodb_force_load_corrupted OFF
innodb_force_recovery 0
innodb_io_capacity 200
innodb_large_prefix OFF
innodb_lock_wait_timeout 50
innodb_locks_unsafe_for_binlog OFF
innodb_log_buffer_size 8388608
innodb_log_file_size 5242880
innodb_log_files_in_group 2
innodb_log_group_home_dir ./
Variable_name Value
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_random_read_ahead OFF
innodb_read_ahead_threshold 56
innodb_read_io_threads 4
innodb_replication_delay 0
innodb_rollback_on_timeout OFF
innodb_rollback_segments 128
innodb_spin_wait_delay 6
innodb_stats_method nulls_equal
innodb_stats_on_metadata ON
innodb_stats_sample_pages 8
innodb_strict_mode OFF
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 ON
innodb_use_sys_malloc ON
innodb_version 1.1.8
innodb_write_io_threads 4
interactive_timeout 28800
join_buffer_size 131072
keep_files_on_create OFF
key_buffer_size 16384
key_cache_age_threshold 300
key_cache_block_size 1024
key_cache_division_limit 100
large_files_support ON
large_page_size 0
large_pages OFF
lc_messages en_US
lc_messages_dir /usr/share/mysql/
lc_time_names en_US
license GPL
local_infile ON
lock_wait_timeout 31536000
locked_in_memory OFF
log OFF
log_bin OFF
log_bin_trust_function_creators OFF
log_error /var/lib/mysql/db.err
log_output FILE
log_queries_not_using_indexes OFF
log_slave_updates OFF
log_slow_queries OFF
log_warnings 1
long_query_time 10.000000
low_priority_updates OFF
lower_case_file_system OFF
lower_case_table_names 0
max_allowed_packet 1048576
max_binlog_cache_size 18446744073709547520
max_binlog_size 1073741824
max_binlog_stmt_cache_size 18446744073709547520
max_connect_errors 10
max_connections 2000
max_delayed_threads 20
max_error_count 64
max_heap_table_size 16777216
max_insert_delayed_threads 20
max_join_size 18446744073709551615
max_length_for_sort_data 1024
max_long_data_size 1048576
max_prepared_stmt_count 16382
max_relay_log_size 0
max_seeks_for_key 18446744073709551615
max_sort_length 1024
max_sp_recursion_depth 0
max_tmp_tables 32
max_user_connections 0
max_write_lock_count 18446744073709551615
metadata_locks_cache_size 1024
min_examined_row_limit 0
multi_range_count 256
myisam_data_pointer_size 6
myisam_max_sort_file_size 9223372036853727232
myisam_mmap_size 18446744073709551615
myisam_recover_options OFF
myisam_repair_threads 1
myisam_sort_buffer_size 8388608
myisam_stats_method nulls_unequal
myisam_use_mmap OFF
net_buffer_length 2048
net_read_timeout 30
net_retry_count 10
net_write_timeout 60
new OFF
old OFF
old_alter_table OFF
old_passwords OFF
open_files_limit 10000
optimizer_prune_level 1
Variable_name Value
optimizer_search_depth 62
optimizer_switch index_merge=on,index_merge_union=on,index_merge_so...
performance_schema OFF
performance_schema_events_waits_history_long_size 10000
performance_schema_events_waits_history_size 10
performance_schema_max_cond_classes 80
performance_schema_max_cond_instances 1000
performance_schema_max_file_classes 50
performance_schema_max_file_handles 32768
performance_schema_max_file_instances 10000
performance_schema_max_mutex_classes 200
performance_schema_max_mutex_instances 1000000
performance_schema_max_rwlock_classes 30
performance_schema_max_rwlock_instances 1000000
performance_schema_max_table_handles 100000
performance_schema_max_table_instances 50000
performance_schema_max_thread_classes 50
performance_schema_max_thread_instances 1000
pid_file /var/run/mysqld/mysqld.pid
plugin_dir /usr/lib64/mysql/plugin
port 3306
preload_buffer_size 32768
profiling OFF
profiling_history_size 15
protocol_version 10
query_alloc_block_size 8192
query_cache_limit 1048576
query_cache_min_res_unit 4096
query_cache_size 8388608
query_cache_type ON
query_cache_wlock_invalidate OFF
query_prealloc_size 8192
range_alloc_block_size 4096
read_buffer_size 262144
read_only OFF
read_rnd_buffer_size 262144
relay_log
relay_log_index
relay_log_info_file relay-log.info
relay_log_purge ON
relay_log_recovery OFF
relay_log_space_limit 0
report_host
report_password
report_port 3306
report_user
rpl_recovery_rank 0
secure_auth OFF
secure_file_priv
server_id 1
skip_external_locking ON
skip_name_resolve ON
skip_networking OFF
skip_show_database OFF
slave_compressed_protocol OFF
slave_exec_mode STRICT
slave_load_tmpdir /tmp
slave_net_timeout 3600
slave_skip_errors OFF
slave_transaction_retries 10
slave_type_conversions
slow_launch_time 2
slow_query_log OFF
slow_query_log_file /var/lib/mysql/slow.log
socket /var/lib/mysql/mysql.sock
sort_buffer_size 32768
sql_auto_is_null OFF
sql_big_selects ON
sql_big_tables OFF
sql_buffer_result OFF
sql_log_bin ON
sql_log_off OFF
sql_low_priority_updates OFF
sql_max_join_size 18446744073709551615
sql_mode
sql_notes ON
sql_quote_show_create ON
sql_safe_updates OFF
sql_select_limit 18446744073709551615
sql_slave_skip_counter 0
sql_warnings OFF
ssl_ca
ssl_capath
ssl_cert
ssl_cipher
ssl_key
storage_engine InnoDB
sync_binlog 0
sync_frm ON
sync_master_info 0
sync_relay_log 0
sync_relay_log_info 0
system_time_zone CET
table_definition_cache 400
table_open_cache 4
thread_cache_size 100
thread_concurrency 8
thread_handling one-thread-per-connection
thread_stack 524288
time_format %H:%i:%s
Variable_name Value
time_zone SYSTEM
timed_mutexes OFF
tmp_table_size 16777216
tmpdir /tmp
transaction_alloc_block_size 8192
transaction_prealloc_size 4096
tx_isolation REPEATABLE-READ
unique_checks ON
updatable_views_with_limit YES
version 5.5.20
version_comment MySQL Community Server (GPL) by Remi
version_compile_machine x86_64
version_compile_os Linux
wait_timeout 28800
答案1
最初的想法是，您有一个进程正在连接到数据库以处理某事，然后在客户端崩溃。它没有正常退出，而是让连接保持打开状态。这会耗尽与 MySQL 的可用连接，最终导致 MySQL 耗尽。引擎并没有挂起，而是耗尽了连接。
启用连接池所做的操作会有所帮助，但您仍然存在同时尝试连接的客户端数量的问题。
ps axf当您看到此问题时，请尝试从命令行运行，以查看正在运行的内容是否可以保持此数量的连接保持打开状态。
答案2
您没有发布有关内存消耗和 I/O 活动的信息。我倾向于认为您的挂起是由于内存过量使用，然后系统交换并导致周期性挂起。
当再次挂起时，发布以下内容的输出：
top -b -n 1
cat /proc/meminfo
free -m