Very high load site, queries taking 70 seconds

[Ben Sebborn]

Hi

I am maintaining a site which has been built very badly. the core of this is a large mysql database (around 7 million rows, 650Mb)

When the site is running, mysql is often at 90% + (copy of top command below)

I dont have time to recode the sytem or the database, so have been looking at optimising (there were no indexes), which is working well, but I could do with a hand checking the main mysql server setup to ensure it is tuned ok. If anyone could have alook at let me know if i have missed anything? So far I've massively reduced the number of opened tables and utilised the query cache quite a bit. There is about 300Mb of index files at the moment.

Spec: dedicated PIII (1 CPU) machine, with 1Gb memory (just purchased) - also runs as webserver

MY.CNF

[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock

skip-locking
key_buffer = 384M
max_allowed_packet = 2M
table_cache = 512
sort_buffer_size = 2M
read_buffer_size = 2M
myisam_sort_buffer_size = 64M
thread_cache = 8
query_cache_size= 32M
# Try number of CPU's*2 for thread_concurrency
thread_concurrency = 2





STATUS


+--------------------------+------------+
| Variable_name | Value |
+--------------------------+------------+
| Aborted_clients | 1295 |
| Aborted_connects | 4 |
| Bytes_received | 1349906823 |
| Bytes_sent | 3409479971 |
| Com_admin_commands | 10018439 |
| Com_alter_table | 7 |
| Com_analyze | 1 |
| Com_backup_table | 0 |
| Com_begin | 0 |
| Com_change_db | 10019759 |
| Com_change_master | 0 |
| Com_check | 10 |
| Com_commit | 0 |
| Com_create_db | 0 |
| Com_create_function | 0 |
| Com_create_index | 0 |
| Com_create_table | 0 |
| Com_delete | 748 |
| Com_delete_multi | 0 |
| Com_drop_db | 0 |
| Com_drop_function | 0 |
| Com_drop_index | 0 |
| Com_drop_table | 0 |
| Com_flush | 0 |
| Com_grant | 0 |
| Com_ha_close | 0 |
| Com_ha_open | 0 |
| Com_ha_read | 0 |
| Com_insert | 15341 |
| Com_insert_select | 0 |
| Com_kill | 1 |
| Com_load | 0 |
| Com_load_master_data | 0 |
| Com_load_master_table | 0 |
| Com_lock_tables | 0 |
| Com_optimize | 7 |
| Com_purge | 0 |
| Com_rename_table | 0 |
| Com_repair | 9 |
| Com_replace | 21253 |
| Com_replace_select | 0 |
| Com_reset | 0 |
| Com_restore_table | 0 |
| Com_revoke | 0 |
| Com_rollback | 0 |
| Com_savepoint | 0 |
| Com_select | 3397310 |
| Com_set_option | 0 |
| Com_show_binlog_events | 0 |
| Com_show_binlogs | 0 |
| Com_show_create | 64 |
| Com_show_databases | 0 |
| Com_show_fields | 369 |
| Com_show_grants | 0 |
| Com_show_keys | 169 |
| Com_show_logs | 0 |
| Com_show_master_status | 0 |
| Com_show_new_master | 0 |
| Com_show_open_tables | 0 |
| Com_show_processlist | 19 |
| Com_show_slave_hosts | 0 |
| Com_show_slave_status | 0 |
| Com_show_status | 2 |
| Com_show_innodb_status | 0 |
| Com_show_tables | 951 |
| Com_show_variables | 21 |
| Com_slave_start | 0 |
| Com_slave_stop | 0 |
| Com_truncate | 0 |
| Com_unlock_tables | 0 |
| Com_update | 57672 |
| Com_update_multi | 0 |
| Connections | 1202 |
| Created_tmp_disk_tables | 3303 |
| Created_tmp_tables | 183713 |
| Created_tmp_files | 484 |
| Delayed_insert_threads | 0 |
| Delayed_writes | 0 |
| Delayed_errors | 0 |
| Flush_commands | 1 |
| Handler_commit | 0 |
| Handler_delete | 392 |
| Handler_read_first | 316 |
| Handler_read_key | 37095210 |
| Handler_read_next | 233314552 |
| Handler_read_prev | 205998 |
| Handler_read_rnd | 17343360 |
| Handler_read_rnd_next | 1229106868 |
| Handler_rollback | 0 |
| Handler_update | 19193 |
| Handler_write | 39870910 |
| Key_blocks_used | 375052 |
| Key_read_requests | 222448212 |
| Key_reads | 759737 |
| Key_write_requests | 18087540 |
| Key_writes | 314543 |
| Max_used_connections | 50 |
| Not_flushed_key_blocks | 0 |
| Not_flushed_delayed_rows | 0 |
| Open_tables | 137 |
| Open_files | 239 |
| Open_streams | 0 |
| Opened_tables | 542 |
| Questions | 20042080 |
| Qcache_queries_in_cache | 29797 |
| Qcache_inserts | 3375364 |
| Qcache_hits | 6525245 |
| Qcache_lowmem_prunes | 2782132 |
| Qcache_not_cached | 21945 |
| Qcache_free_memory | 430664 |
| Qcache_free_blocks | 2 |
| Qcache_total_blocks | 59646 |
| Rpl_status | NULL |
| Select_full_join | 1 |
| Select_full_range_join | 0 |
| Select_range | 5714 |
| Select_range_check | 0 |
| Select_scan | 409669 |
| Slave_open_temp_tables | 0 |
| Slave_running | OFF |
| Slow_launch_threads | 1 |
| Slow_queries | 69 |
| Sort_merge_passes | 239 |
| Sort_range | 6218 |
| Sort_rows | 27808832 |
| Sort_scan | 53669 |
| Table_locks_immediate | 3802415 |
| Table_locks_waited | 448 |
| Threads_cached | 6 |
| Threads_created | 156 |
| Threads_connected | 19 |
| Threads_running | 1 |
| Uptime | 254760 |
+--------------------------+------------+
133 rows in set (0.00 sec)







THANKS!!!
Ben