How do I allow mysqld to use more than 24.9% of my cpu?
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Joseph Yancey
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Published on 2011-01-08T09:51:45Z
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2011/01/08
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I have a Web server running on RHEL that is running Apache and MySQL. It has a Quad core 3.2Ghz Xeon CPU and 8 Gigs of RAM Most of the time, we don't have any issues at all.
Our web application is very database intensive. When our usage gets pretty heavy MySQL will peg out at using 24.9% of the cpu. Most of the time, it hangs around below 5%. I have speculated that it is only using one core of the CPU and it is pegging out that core but TOP shows me in the cpu column that mysqld changes cores even while the usage stays at 24.9%. When it does this MySQL gets painfully slow as it is queuing up queries Is there some magic configuration that will tell mysql to use more cpu when it needs to? Also, any other advice on my configuration would be helpful.
We run two applications on this server. One that runs Innodb but doesn't get much usage (it has been replaced by the other app), and one that runs MyIsam and gets lots of use. Overall, our whole mysql data directory is something like 13Gigs if that matters at all.
Here is my config:
[root@ProductionLinux root]# cat /etc/my.cnf [mysqld] server-id = 71 log-bin = /var/log/mysql/mysql-bin.log binlog-do-db = oldapplication binlog-do-db = newapplication binlog-do-db = support thread_cache_size = 30 key_buffer_size = 256M table_cache = 256 sort_buffer_size = 4M read_buffer_size = 1M skip-name-resolve innodb_data_home_dir = /usr/local/mysql/data/ innodb_data_file_path = InnoDB:100M:autoextend set-variable = innodb_buffer_pool_size=70M set-variable = innodb_additional_mem_pool_size=10M set-variable = max_connections=500 innodb_log_group_home_dir = /usr/local/mysql/data innodb_log_arch_dir = /usr/local/mysql/data set-variable = innodb_log_file_size=20M set-variable = innodb_log_buffer_size=8M innodb_flush_log_at_trx_commit = 1 log-queries-not-using-indexes log-error = /var/log/mysql/mysql-error.log
mysql> show variables; +---------------------------------+-----------------------------------------------------------------------------+ | Variable_name | Value | +---------------------------------+-----------------------------------------------------------------------------+ | auto_increment_increment | 1 | | auto_increment_offset | 1 | | automatic_sp_privileges | ON | | back_log | 50 | | basedir | /usr/local/mysql-standard-5.0.18-linux-x86_64-glibc23/ | | binlog_cache_size | 32768 | | bulk_insert_buffer_size | 8388608 | | character_set_client | latin1 | | character_set_connection | latin1 | | character_set_database | latin1 | | character_set_results | latin1 | | character_set_server | latin1 | | character_set_system | utf8 | | character_sets_dir | /usr/local/mysql-standard-5.0.18-linux-x86_64-glibc23/share/mysql/charsets/ | | collation_connection | latin1_swedish_ci | | collation_database | latin1_swedish_ci | | collation_server | latin1_swedish_ci | | completion_type | 0 | | concurrent_insert | 1 | | connect_timeout | 5 | | datadir | /usr/local/mysql/data/ | | date_format | %Y-%m-%d | | datetime_format | %Y-%m-%d %H:%i:%s | | 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 | OFF | | expire_logs_days | 0 | | flush | OFF | | flush_time | 0 | | | ft_max_word_len | 84 | | ft_min_word_len | 4 | | ft_query_expansion_limit | 20 | | ft_stopword_file | (built-in) | | group_concat_max_len | 1024 | | have_archive | YES | | have_bdb | NO | | have_blackhole_engine | NO | | have_compress | YES | | have_crypt | YES | | have_csv | NO | | have_example_engine | NO | | have_federated_engine | NO | | have_geometry | YES | | have_innodb | YES | | have_isam | NO | | have_ndbcluster | NO | | have_openssl | NO | | have_query_cache | YES | | have_raid | NO | | have_rtree_keys | YES | | have_symlink | YES | | init_connect | | | init_file | | | init_slave | | | innodb_additional_mem_pool_size | 10485760 | | innodb_autoextend_increment | 8 | | innodb_buffer_pool_awe_mem_mb | 0 | | innodb_buffer_pool_size | 73400320 | | innodb_checksums | ON | | innodb_commit_concurrency | 0 | | innodb_concurrency_tickets | 500 | | innodb_data_file_path | InnoDB:100M:autoextend | | innodb_data_home_dir | /usr/local/mysql/data/ | | innodb_doublewrite | ON | | innodb_fast_shutdown | 1 | | innodb_file_io_threads | 4 | | innodb_file_per_table | OFF | | innodb_flush_log_at_trx_commit | 1 | | innodb_flush_method | | | innodb_force_recovery | 0 | | innodb_lock_wait_timeout | 50 | | innodb_locks_unsafe_for_binlog | OFF | | innodb_log_arch_dir | /usr/local/mysql/data | | innodb_log_archive | OFF | | innodb_log_buffer_size | 8388608 | | innodb_log_file_size | 20971520 | | innodb_log_files_in_group | 2 | | innodb_log_group_home_dir | /usr/local/mysql/data | | innodb_max_dirty_pages_pct | 90 | | innodb_max_purge_lag | 0 | | innodb_mirrored_log_groups | 1 | | innodb_open_files | 300 | | innodb_support_xa | ON | | innodb_sync_spin_loops | 20 | | innodb_table_locks | ON | | innodb_thread_concurrency | 20 | | innodb_thread_sleep_delay | 10000 | | interactive_timeout | 28800 | | join_buffer_size | 131072 | | key_buffer_size | 268435456 | | key_cache_age_threshold | 300 | | key_cache_block_size | 1024 | | key_cache_division_limit | 100 | | language | /usr/local/mysql-standard-5.0.18-linux-x86_64-glibc23/share/mysql/english/ | | large_files_support | ON | | large_page_size | 0 | | large_pages | OFF | | license | GPL | | local_infile | ON | | locked_in_memory | OFF | | log | OFF | | log_bin | ON | | log_bin_trust_function_creators | OFF | | log_error | /var/log/mysql/mysql-error.log | | log_slave_updates | OFF | | log_slow_queries | OFF | | log_warnings | 1 | | long_query_time | 10 | | low_priority_updates | OFF | | lower_case_file_system | OFF | | lower_case_table_names | 0 | | max_allowed_packet | 1048576 | | max_binlog_cache_size | 18446744073709551615 | | max_binlog_size | 1073741824 | | max_connect_errors | 10 | | max_connections | 500 | | 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_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 | | multi_range_count | 256 | | myisam_data_pointer_size | 6 | | myisam_max_sort_file_size | 9223372036854775807 | | myisam_recover_options | OFF | | myisam_repair_threads | 1 | | myisam_sort_buffer_size | 8388608 | | myisam_stats_method | nulls_unequal | | net_buffer_length | 16384 | | net_read_timeout | 30 | | net_retry_count | 10 | | net_write_timeout | 60 | | new | OFF | | old_passwords | OFF | | open_files_limit | 2510 | | optimizer_prune_level | 1 | | optimizer_search_depth | 62 | | pid_file | /usr/local/mysql/data/ProductionLinux.pid | | port | 3306 | | preload_buffer_size | 32768 | | protocol_version | 10 | | query_alloc_block_size | 8192 | | query_cache_limit | 1048576 | | query_cache_min_res_unit | 4096 | | query_cache_size | 0 | | query_cache_type | ON | | query_cache_wlock_invalidate | OFF | | query_prealloc_size | 8192 | | range_alloc_block_size | 2048 | | read_buffer_size | 1044480 | | read_only | OFF | | read_rnd_buffer_size | 262144 | | relay_log_purge | ON | | relay_log_space_limit | 0 | | rpl_recovery_rank | 0 | | secure_auth | OFF | | server_id | 71 | | skip_external_locking | ON | | skip_networking | OFF | | skip_show_database | OFF | | slave_compressed_protocol | OFF | | slave_load_tmpdir | /tmp/ | | slave_net_timeout | 3600 | | slave_skip_errors | OFF | | slave_transaction_retries | 10 | | slow_launch_time | 2 | | socket | /tmp/mysql.sock | | sort_buffer_size | 4194296 | | sql_mode | | | sql_notes | ON | | sql_warnings | ON | | storage_engine | MyISAM | | sync_binlog | 0 | | sync_frm | ON | | sync_replication | 0 | | sync_replication_slave_id | 0 | | sync_replication_timeout | 10 | | system_time_zone | CST | | table_cache | 256 | | table_lock_wait_timeout | 50 | | table_type | MyISAM | | thread_cache_size | 30 | | thread_stack | 262144 | | time_format | %H:%i:%s | | time_zone | SYSTEM | | timed_mutexes | OFF | | tmp_table_size | 33554432 | | tmpdir | | | transaction_alloc_block_size | 8192 | | transaction_prealloc_size | 4096 | | tx_isolation | REPEATABLE-READ | | updatable_views_with_limit | YES | | version | 5.0.18-standard-log | | version_comment | MySQL Community Edition - Standard (GPL) | | version_compile_machine | x86_64 | | version_compile_os | unknown-linux-gnu | | wait_timeout | 28800 | +---------------------------------+-----------------------------------------------------------------------------+ 210 rows in set (0.00 sec)
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