J'utilise MEMORY Enginepour toutes les tables associées à une requête MYSQL particulière car la vitesse d'accès est primordiale pour mon projet.
Pour une raison quelconque, j'ai remarqué qu'une grande quantité d'écriture sur disque se produit toujours.
Est-ce parce que Windows a échangé la RAM sur le disque? Comment puis-je empêcher que cela se produise?
Edit: Voici mes variables globales:
mysql> show global variables;
+---------------------------------------------------+--------------------------------------------------------------------------------
------------------------------+
| Variable_name | Value
|
+---------------------------------------------------+--------------------------------------------------------------------------------
------------------------------+
| auto_increment_increment | 1
|
| auto_increment_offset | 1
|
| autocommit | ON
|
| automatic_sp_privileges | ON
|
| back_log | 50
|
| basedir | C:/Program Files/MySQL/MySQL Server 5.5/
|
| big_tables | OFF
|
| binlog_cache_size | 32768
|
| binlog_direct_non_transactional_updates | OFF
|
| binlog_format | STATEMENT
|
| binlog_stmt_cache_size | 4096
|
| 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 | C:\Program Files\MySQL\MySQL Server 5.5\share\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 | C:\ProgramData\MySQL\MySQL Server 5.5\Data\
|
| date_format | %Y-%m-%d
|
| datetime_format | %Y-%m-%d %H:%i:%s
|
| default_storage_engine | MyISAM
|
| default_week_format | 0
|
| delay_key_write | OFF
|
| 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 | 1800
|
| foreign_key_checks | ON
|
| ft_boolean_syntax | + -><()~*:""&|
|
| ft_max_word_len | 84
|
| ft_min_word_len | 4
|
| ft_query_expansion_limit | 20
|
| ft_stopword_file | (built-in)
|
| general_log | OFF
|
| general_log_file | C:\ProgramData\MySQL\MySQL Server 5.5\Data\FXMachine.log
|
| group_concat_max_len | 1024
|
| have_compress | YES
|
| have_crypt | NO
|
| have_csv | YES
|
| have_dynamic_loading | YES
|
| have_geometry | YES
|
| have_innodb | DISABLED
|
| 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 | FXMachine
|
| ignore_builtin_innodb | OFF
|
| init_connect |
|
| init_file |
|
| init_slave |
|
| interactive_timeout | 28800
|
| join_buffer_size | 25600
|
| keep_files_on_create | OFF
|
| key_buffer_size | 25165824
|
| 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 | C:\Program Files\MySQL\MySQL Server 5.5\share\
|
| lc_time_names | en_US
|
| license | GPL
|
| local_infile | ON
|
| lock_wait_timeout | 31536000
|
| log | OFF
|
| log_bin | OFF
|
| log_bin_trust_function_creators | OFF
|
| log_error | C:\ProgramData\MySQL\MySQL Server 5.5\Data\FXMachine.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 | ON
|
| lower_case_table_names | 1
|
| max_allowed_packet | 1048576
|
| max_binlog_cache_size | 4096
|
| max_binlog_size | 4096
|
| max_binlog_stmt_cache_size | 4096
|
| max_connect_errors | 10
|
| max_connections | 10
|
| max_delayed_threads | 20
|
| max_error_count | 64
|
| max_heap_table_size | 134217728
|
| 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 | 4294967295
|
| max_sort_length | 1024
|
| max_sp_recursion_depth | 0
|
| max_tmp_tables | 32
|
| max_user_connections | 0
|
| max_write_lock_count | 4294967295
|
| min_examined_row_limit | 0
|
| multi_range_count | 256
|
| myisam_data_pointer_size | 6
|
| myisam_max_sort_file_size | 2146435072
|
| 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
|
| named_pipe | ON
|
| net_buffer_length | 16384
|
| 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 | 2324
|
| optimizer_prune_level | 1
|
| optimizer_search_depth | 62
|
| optimizer_switch | index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_inter
,engine_condition_pushdown=on |
| 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 | C:\ProgramData\MySQL\MySQL Server 5.5\Data\FXMachine.pid
|
| plugin_dir | C:\Program Files\MySQL\MySQL Server 5.5\lib/plugin
|
| port | 0
|
| 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 | 0
|
| query_cache_type | OFF
|
| query_cache_wlock_invalidate | OFF
|
| query_prealloc_size | 8192
|
| range_alloc_block_size | 4096
|
| read_buffer_size | 67108864
|
| read_only | OFF
|
| read_rnd_buffer_size | 4194304
|
| 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 | 0
|
| shared_memory | OFF
|
| shared_memory_base_name | MYSQL
|
| skip_external_locking | ON
|
| skip_name_resolve | OFF
|
| skip_networking | ON
|
| skip_show_database | OFF
|
| slave_compressed_protocol | OFF
|
| slave_exec_mode | STRICT
|
| slave_load_tmpdir | C:\Windows\TEMP
|
| 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 | C:\ProgramData\MySQL\MySQL Server 5.5\Data\FXMachine-slow.log
|
| socket | mysql
|
| sort_buffer_size | 32768
|
| sql_auto_is_null | OFF
|
| sql_big_selects | ON
|
| sql_big_tables | OFF
|
| sql_buffer_result | OFF
|
| sql_log_bin | OFF
|
| sql_log_off | OFF
|
| sql_low_priority_updates | OFF
|
| sql_max_join_size | 18446744073709551615
|
| sql_mode | STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
|
| 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 | MyISAM
|
| sync_binlog | 0
|
| sync_frm | ON
|
| sync_master_info | 0
|
| sync_relay_log | 0
|
| sync_relay_log_info | 0
|
| system_time_zone | Eastern Daylight Time
|
| table_definition_cache | 400
|
| table_open_cache | 128
|
| thread_cache_size | 0
|
| thread_concurrency | 10
|
| thread_handling | one-thread-per-connection
|
| thread_stack | 262144
|
| time_format | %H:%i:%s
|
| time_zone | SYSTEM
|
| timed_mutexes | OFF
|
| tmp_table_size | 134217728
|
| tmpdir | C:\Windows\TEMP
|
| transaction_alloc_block_size | 8192
|
| transaction_prealloc_size | 4096
|
| tx_isolation | REPEATABLE-READ
|
| unique_checks | ON
|
| updatable_views_with_limit | YES
|
| version | 5.5.11
|
| version_comment | MySQL Community Server (GPL)
|
| version_compile_machine | x86
|
| version_compile_os | Win64
|
| wait_timeout | 28800
|
+---------------------------------------------------+--------------------------------------------------------------------------------
mysql
memory
storage-engine
Mike Furlender
la source
la source
Réponses:
Vous voudrez peut-être voir combien de tables MEMORY vous utilisez. Même avec une table MEMORY, il doit y avoir un descripteur de fichier ouvert vers le .frm de la table MEMORY. Vérifiez votre open_files_limit. Vous devrez peut-être augmenter cela également.
Vous avez également une grande disparité entre read_buffer_size et read_rnd_buffer_size.
Vous avez read_buffer_size à 64M et read_rnd_buffer_size à 4M.
Je n'ai jamais vu de configuration avec read_buffer_size beaucoup plus grande que read_rnd_buffer_size
Vous devez le faire comme suit:
Ces éléments contribuent à lire les E / S et non à écrire des E / S.
Voici quelque chose à considérer:
Avez-vous d'autres tables utilisant MyISAM ???
Exécutez-vous des requêtes JOIN qui mélangent des tables MEMORY et des tables MyISAM ???
Les tables temporaires dépassent-elles 128M ??
la source
Les E / S d'écriture étaient le résultat d' instructions
DROP TABLE/ répétéesCREATE TABLE. J'ai remplacé ceux-ci parTRUNCATE TABLEet le problème a disparu.la source
Je pense qu'il est temps de faire quelques calculs. Quel est votre RAM système par rapport à la taille de la table que vous essayez d'y insérer? Quelle est la taille de la structure (exigences de stockage de données de chaque ligne) que vous stockez dans votre table mémoire?
Avez-vous multiplié ces * quantités pour voir si cela dépasse vos valeurs?
http://dev.mysql.com/doc/refman/5.0/en/memory-storage-engine.html
Autres réflexions: Vos limites pour tmp_table_size et max_heap_table_size sont de 128 Mo, mais votre key_buffer est de 24 Mo? Impair. En outre, vos tampons de jointure et de tri semblent être assez petits. J'expérimenterais en augmentant votre key_buffer à 128M.
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