I’d like to ask your help on a longstanding issue with php/mysql connections.
Every time I execute a “SHOW PROCESSLIST” command it shows me about 400 idle (Status: Sleep) connections to the database Server emerging from our 5 Webservers.
That never was much of a problem (and I didn’t find a quick solution) until recently traffic numbers increased and since then MySQL reports the “to many connections” Problems repeatedly, even so 350+ of those connections are in “sleep” state. Also a server can’t get a MySQL connection even if there are sleeping connection to that same server.
All those connections vanish when an apache server is restated.
The PHP Code used to create the Database connections uses the normal “mysql” Module, the “mysqli” Module, PEAR::DB and Zend Framework Db Adapter. (Different projects). NONE of the projects uses persistent connections.
Raising the connection-limit is possible but doesn’t seem like a good solution since it’s 450 now and there are only 20-100 “real” connections at a time anyways.
My question:
Why are there so many connections in sleep state and how can I prevent that?
— Update:
The Number of Apache requests running at a time never exceeds 50 concurrent requests, so i guess there is a problem with closing the connection or apache keeps the port open without a phpscript attached or something (?)
my.cnf in case it’s helpful:
innodb_buffer_pool_size = 1024M
max_allowed_packet = 5M
net_buffer_length = 8K
read_buffer_size = 2M
read_rnd_buffer_size = 8M
query_cache_size = 512M
myisam_sort_buffer_size = 128M
max_connections = 450
thread_cache = 50
key_buffer_size = 1280M
join_buffer_size = 16M
table_cache = 2048
sort_buffer_size = 64M
tmp_table_size = 512M
max_heap_table_size = 512M
thread_concurrency = 8
log-slow-queries = /daten/mysql-log/slow-log
long_query_time = 1
log_queries_not_using_indexes
innodb_additional_mem_pool_size = 64M
innodb_log_file_size = 64M
innodb_log_buffer_size = 8M
innodb_flush_log_at_trx_commit = 2
innodb_file_per_table