I have a problem with a MySql server causing it to freeze all the time. In phpMyAdmin when this happens I can see in "Show Processlist" are lots of processes for User "unauthenticated user" with Command "connect" and State "reading from net".
The database is using InnoDB but I also use one table running MyISAM to be able to perform full text search. The server has about 4GB memory, less than 1GB in use.
I have been using the slow Query Log from MySql to find the queries not using indexes. I also think I need to do some changes / tweaking on the server variables. I really could use some help here and therefore I'm posting both SHOW GLOBAL STATUS and SHOW GLOBAL VARIABLES here and maybe you can give me some ideas how I should set the variables?
EDIT: I realized I was using pooling=false in my connection string to the database. I changed this to default pooling=true and now the performance seems much better. Could that have been the problem?
Current SHOW GLOBAL STATUS:
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
Com_show_contributors 0
Com_show_create_db 0
Com_show_create_event 0
Com_show_create_func 0
Com_show_create_proc 0
Com_show_create_table 1777
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
Com_show_events 0
Com_show_errors 0
Com_show_fields 1247
Com_show_function_status 1
Com_show_grants 2
Com_show_keys 0
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
Com_show_table_status 1187
Com_show_tables 78
Com_show_triggers 1184
Com_show_variables 6596881
Com_show_warnings 586
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_reprepare 0
Com_stmt_reset 0
Com_stmt_send_long_data 0
Com_truncate 0
Com_uninstall_plugin 0
Com_unlock_tables 48
Com_update 659355
Com_update_multi 8320
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 OFF
Connections 6597009
Created_tmp_disk_tables 25939
Created_tmp_files 17999
Created_tmp_tables 14262327
Delayed_errors 0
Delayed_insert_threads 0
Delayed_writes 0
Flush_commands 1
Handler_commit 6316749
Handler_delete 51862
Handler_discover 0
Handler_prepare 0
Handler_read_first 264718
Handler_read_key 461015559
Handler_read_last 1132
Handler_read_next 927027451
Handler_read_prev 898395515
Handler_read_rnd 2145244
Handler_read_rnd_next 3970915350
Handler_rollback 133
Handler_savepoint 0
Handler_savepoint_rollback 0
Handler_update 2718211
Handler_write 3653943074
Innodb_buffer_pool_pages_data 54158
Innodb_buffer_pool_pages_dirty 496
Innodb_buffer_pool_pages_flushed 8415286
Innodb_buffer_pool_pages_free 1
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
Innodb_buffer_pool_read_requests 3339098369
Innodb_buffer_pool_reads 5192591
Innodb_buffer_pool_wait_free 0
Innodb_buffer_pool_write_requests 16630766
Innodb_data_fsyncs 2177985
Innodb_data_pending_fsyncs 0
Innodb_data_pending_reads 0
Innodb_data_pending_writes 0
Innodb_data_read 103331024896
Innodb_data_reads 6306700
Innodb_data_writes 6345720
Innodb_data_written 139541615616
Innodb_dblwr_pages_written 4207643
Innodb_dblwr_writes 73094
Innodb_have_atomic_builtins ON
Innodb_log_waits 0
Innodb_log_write_requests 1261730
Innodb_log_writes 1998194
Innodb_os_log_fsyncs 2032461
Variable_name Value
Innodb_os_log_pending_fsyncs 0
Innodb_os_log_pending_writes 0
Innodb_os_log_written 1648348672
Innodb_page_size 16384
Innodb_pages_created 20015
Innodb_pages_read 6306691
Innodb_pages_written 4207643
Innodb_row_lock_current_waits 0
Innodb_row_lock_time 3
Innodb_row_lock_time_avg 1
Innodb_row_lock_time_max 1
Innodb_row_lock_waits 2
Innodb_rows_deleted 51862
Innodb_rows_inserted 1444543
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
Current SHOW GLOBAL VARIABLES:
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
Initial thought is that you have a process that is connecting to the database for something and then crashing at the client end. It's not exiting gracefully and is leaving the connection open. This is using up the available connections to MySQL and eventually MySQL runs out. The engine isn't so much as hanging but running out of connections.
What you've done by enabling connection pooling will help, but you still have the issue of the number of clients trying to connect at once.
Try running
ps axffrom the command line while you're seeing this problem to see what is running that could be holding this number of connections open.You've not posted information about memory consumption and I/O activity. I would be inclined to think your hang stems from an over commit on memory, then the system swapping and causing a periodic hang.
Post the output from the following when it hangs again: