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low performance - what am i doing wrong? [message #3087] Fri, 16 May 2008 08:12 Go to previous message
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Messages: 6
Registered: May 2008
Location: UK
Junior Member
Could anyone tell me what is wrong - after ive put the database on the server query takes ages to execute:

SELECT company.company_id,company.enhancement 
FROM company LEFT JOIN company_in_cat_100 
ON company.company_id = company_in_cat_100.company_id 
where company_in_cat_100.category_id =53;

1st run: 39627 rows in set (1 min 50.44 sec)
later : ~10 sec

I dont really understand why - I have tested everything on my local machine, and it was maximum 0,5-1,2sec.

Structure dump:
CREATE TABLE `company_in_cat_100` (
  `id` mediumint(7) NOT NULL auto_increment,
  `company_id` mediumint(7) unsigned NOT NULL default '0',
  `category_id` smallint(4) unsigned NOT NULL default '0',
  PRIMARY KEY  (`id`),
  KEY `category_id` (`category_id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=158105 ;


CREATE TABLE `company` (
  `company_id` mediumint(7) unsigned NOT NULL auto_increment,
  `name` varchar(100) NOT NULL default '',
  `add1` varchar(64) NOT NULL default '',
  `add2` varchar(64) NOT NULL default '',
  `add3` varchar(64) NOT NULL default '',
  `town_id` smallint(4) unsigned NOT NULL default '0',
  `county_id` mediumint(6) unsigned NOT NULL default '0',
  `postcode` varchar(9) NOT NULL default '',
  `telephone` varchar(30) NOT NULL default '',
  `description_text` varchar(255) NOT NULL default '',
  `enhancement` tinyint(1) NOT NULL default '0',
  PRIMARY KEY  (`company_id`),
  KEY `name` (`name`),
  KEY `town` (`town_id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=1707942 ;


Explein Query:
+----+-------------+--------------------+--------+---------------+-------------+---------+-----------------------------------------------+-------+-------------+
| id | select_type | table              | type   | possible_keys | key         | key_len | ref                                           | rows  | Extra       |
+----+-------------+--------------------+--------+---------------+-------------+---------+-----------------------------------------------+-------+-------------+
|  1 | SIMPLE      | company_in_cat_100 | ref    | category_id   | category_id |       2 | const                                         | 34695 | Using where |
|  1 | SIMPLE      | company            | eq_ref | PRIMARY       | PRIMARY     |       3 | thisisbusnew_en.company_in_cat_100.company_id |     1 |             |
+----+-------------+--------------------+--------+---------------+-------------+---------+-----------------------------------------------+-------+-------------+


Show variables:
+---------------------------------+----------------------------------------------+
| Variable_name                   | Value                                        |
+---------------------------------+----------------------------------------------+
| back_log                        | 50                                           |
| basedir                         | /                                            |
| 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/share/mysql/charsets/                   |
| collation_connection            | latin1_swedish_ci                            |
| collation_database              | latin1_swedish_ci                            |
| collation_server                | latin1_swedish_ci                            |
| concurrent_insert               | ON                                           |
| connect_timeout                 | 5                                            |
| datadir                         | /var/lib/mysql/                              |
| 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                                         |
| expire_logs_days                | 0                                            |
| flush                           | OFF                                          |
| flush_time                      | 0                                            |
| ft_boolean_syntax               | + -><()~*:""&|                               |
| 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                    | NO                                           |
| have_bdb                        | NO                                           |
| have_blackhole_engine           | NO                                           |
| have_compress                   | YES                                          |
| have_crypt                      | YES                                          |
| have_csv                        | NO                                           |
| have_example_engine             | NO                                           |
| have_geometry                   | YES                                          |
| have_innodb                     | YES                                          |
| have_isam                       | NO                                           |
| have_merge_engine               | YES                                          |
| 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 | 1048576                                      |
| innodb_autoextend_increment     | 8                                            |
| innodb_buffer_pool_awe_mem_mb   | 0                                            |
| innodb_buffer_pool_size         | 8388608                                      |
| innodb_data_file_path           | ibdata1:10M:autoextend                       |
| innodb_data_home_dir            |                                              |
| innodb_fast_shutdown            | ON                                           |
| 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             |                                              |
| innodb_log_archive              | OFF                                          |
| innodb_log_buffer_size          | 1048576                                      |
| innodb_log_file_size            | 5242880                                      |
| innodb_log_files_in_group       | 2                                            |
| innodb_log_group_home_dir       | ./                                           |
| innodb_max_dirty_pages_pct      | 90                                           |
| innodb_max_purge_lag            | 0                                            |
| innodb_mirrored_log_groups      | 1                                            |
| innodb_open_files               | 300                                          |
| innodb_table_locks              | ON                                           |
| innodb_thread_concurrency       | 8                                            |
| interactive_timeout             | 28800                                        |
| join_buffer_size                | 131072                                       |
| key_buffer_size                 | 8388600                                      |
| key_cache_age_threshold         | 300                                          |
| key_cache_block_size            | 1024                                         |
| key_cache_division_limit        | 100                                          |
| language                        | /usr/share/mysql/english/                    |
| large_files_support             | ON                                           |
| lc_time_names                   | en_US                                        |
| license                         | GPL                                          |
| local_infile                    | ON                                           |
| locked_in_memory                | OFF                                          |
| log                             | OFF                                          |
| log_bin                         | OFF                                          |
| log_error                       |                                              |
| log_slave_updates               | OFF                                          |
| log_slow_queries                | OFF                                          |
| log_update                      | 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           | 4294967295                                   |
| max_binlog_size                 | 1073741824                                   |
| max_connect_errors              | 10                                           |
| max_connections                 | 100                                          |
| max_delayed_threads             | 20                                           |
| max_error_count                 | 64                                           |
| max_heap_table_size             | 16777216                                     |
| max_insert_delayed_threads      | 20                                           |
| max_join_size                   | 4294967295                                   |
| max_length_for_sort_data        | 1024                                         |
| max_prepared_stmt_count         | 16382                                        |
| max_relay_log_size              | 0                                            |
| max_seeks_for_key               | 4294967295                                   |
| max_sort_length                 | 1024                                         |
| max_tmp_tables                  | 32                                           |
| max_user_connections            | 0                                            |
| max_write_lock_count            | 4294967295                                   |
| myisam_data_pointer_size        | 4                                            |
| myisam_max_extra_sort_file_size | 2147483648                                   |
| myisam_max_sort_file_size       | 2147483647                                   |
| 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                   | ON                                           |
| open_files_limit                | 1024                                         |
| pid_file                        | /var/lib/mysql/STEAM3.POBOXHOSTING.CO.UK.pid |
| port                            | 3306                                         |
| preload_buffer_size             | 32768                                        |
| prepared_stmt_count             | 0                                            |
| 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                | 131072                                       |
| 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                       | 0                                            |
| skip_external_locking           | ON                                           |
| skip_networking                 | OFF                                          |
| skip_show_database              | OFF                                          |
| slave_net_timeout               | 3600                                         |
| slave_transaction_retries       | 0                                            |
| slow_launch_time                | 2                                            |
| socket                          | /var/lib/mysql/mysql.sock                    |
| sort_buffer_size                | 2097144                                      |
| 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        | 0                                            |
| system_time_zone                | BST                                          |
| table_cache                     | 64                                           |
| table_type                      | MyISAM                                       |
| thread_cache_size               | 0                                            |
| thread_stack                    | 196608                                       |
| time_format                     | %H:%i:%s                                     |
| time_zone                       | SYSTEM                                       |
| tmp_table_size                  | 33554432                                     |
| tmpdir                          |                                              |
| transaction_alloc_block_size    | 8192                                         |
| transaction_prealloc_size       | 4096                                         |
| tx_isolation                    | REPEATABLE-READ                              |
| version                         | 4.1.22-standard                              |
| version_comment                 | MySQL Community Edition - Standard (GPL)     |
| version_compile_machine         | i686                                         |
| version_compile_os              | pc-linux-gnu                                 |
| wait_timeout                    | 28800                                        |
+---------------------------------+----------------------------------------------+


System:linux with 512 RAM memory
One more thing - while running query mysql uses only 3% of CPU.
Ive tried everything. Please let me know what you think.

[Updated on: Fri, 16 May 2008 08:14]

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