This happen to me in my Master DB. Due to too many "query end" it becoming slow.
What is possible problem and how to solve this?
Below is my cnf
#Custom
max_connections=500
max_connect_errors=99999
expire_logs_days = 2
max_binlog_size = 1G
#Replication purpose
server-id=1
binlog-do-db=pencilm_running
binlog-format = mixed
log-bin=mysql-bin
innodb_flush_log_at_trx_commit=1
sync_binlog=0
#Performance issue
thread_cache_size=30
query_cache_size=256M
query_cache_type=1
query_cache_limit=1M
slow_query_log=1
group_concat_max_len = 5000
#join_buffer_size = 250000