mysqld intermittent restarts under load - mysql

Question

To start with, I'm relatively new to web development.
Under reasonable load (500-700 Q/s) the server is restarting frequently (sometimes every hour), and I get the follow in my syslog each time it happens. I don't get any output to mysql.err or mysql/error.log
This is my first real mysql setup, so I'm sure there is lots that could be improved, but I'm surprised that the server is actually going down so often. The machine has 4GB of ram. Thanks for any suggestions or help!
Ubuntu 10.04, mysql is from the lucid packages.
Ver 14.14 Distrib 5.1.41, for debian-linux-gnu (x86_64) using readline 6.1
Oct 10 01:45:33 host init: mysql main process (1199) terminated with status 1
Oct 10 01:45:33 host init: mysql main process ended, respawning
Oct 10 01:45:42 host /etc/mysql/debian-start[1644]: Upgrading MySQL tables if necessary.
Oct 10 01:45:42 host /etc/mysql/debian-start[1648]: /usr/bin/mysql_upgrade: the '--basedir' option is always ignored
Oct 10 01:45:42 host /etc/mysql/debian-start[1648]: Looking for 'mysql' as: /usr/bin/mysql
Oct 10 01:45:42 host /etc/mysql/debian-start[1648]: Looking for 'mysqlcheck' as: /usr/bin/mysqlcheck
Oct 10 01:45:42 host /etc/mysql/debian-start[1648]: This installation of MySQL is already upgraded to 5.1.41, use --force if you still need to run mysql_upgrade
Oct 10 01:45:42 host /etc/mysql/debian-start[1656]: Checking for insecure root accounts.
Oct 10 01:45:43 host /etc/mysql/debian-start[1672]: Triggering myisam-recover for all MyISAM tables
Here's my my.cnf:
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock
[mysqld]
user = mysql
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
skip-external-locking
bind-address = host
back_log = 50
max_connections = 100
max_connect_errors = 10
table_open_cache = 2048
max_allowed_packet = 16M
binlog_cache_size = 1M
max_heap_table_size = 64M
sort_buffer_size = 8M
join_buffer_size = 8M
thread_cache_size = 8
thread_concurrency = 8
query_cache_size = 64M
query_cache_limit = 2M
ft_min_word_len = 4
default-storage-engine = innodb
default-character-set = utf8
thread_stack = 192K
transaction_isolation = REPEATABLE-READ
tmp_table_size = 32M
log-bin=trent-bin
binlog_format=mixed
slow_query_log
long_query_time = 2
server-id = 1
key_buffer_size = 32M
read_buffer_size = 2M
read_rnd_buffer_size = 16M
bulk_insert_buffer_size = 64M
myisam_sort_buffer_size = 128M
myisam_max_sort_file_size = 10G
myisam_repair_threads = 1
myisam_recover
innodb_additional_mem_pool_size = 16M
innodb_buffer_pool_size = 2800M
innodb_data_file_path = ibdata1:100M:autoextend
innodb_file_per_table
innodb_file_io_threads = 4
innodb_thread_concurrency = 8
innodb_flush_log_at_trx_commit = 2
innodb_log_buffer_size = 4M
innodb_log_file_size = 256M
innodb_log_files_in_group = 3
innodb_max_dirty_pages_pct = 90
innodb_flush_method=O_DIRECT
innodb_lock_wait_timeout = 50
ssl-ca=/etc/mysql/cacert.pem
ssl-cert=/etc/mysql/server-cert.pem
ssl-key=/etc/mysql/server-key.pem
[mysqldump]
quick
max_allowed_packet = 16M
[mysql]
no-auto-rehash
[myisamchk]
key_buffer_size = 512M
sort_buffer_size = 512M
read_buffer = 8M
write_buffer = 8M
[mysqlhotcopy]
interactive-timeout
[mysqld_safe]
open-files-limit = 8192

Answer 1

I have seen mysql behave this way a few times, there are many potential causes.. : to investigatem I would check
1) are there any custom functions that you have written that might be memory leaks? I once saw a median function, custom written on mysql 5, lead to restarts if it was run by two simultaneous queries...
2) if you optimize the tables, does this reduce the restart frequency?
3) are therea ny corrupt tables in the db ?