mysql 访问量过大，造成链接不上的情况
硬件：16核心CPU ，32G内存，100M带宽
软件，php5.6,+mysql 5.7
用途，接口调用
mysql 基本配置：
[client]
#password = your_password
port = 3306
socket = /tmp/mysql.sock
[mysqld]
binlog_cache_size = 192K
thread_stack = 384K
join_buffer_size = 4096K
query_cache_type = 0
max_heap_table_size = 1024M
port = 3306
socket = /tmp/mysql.sock
datadir = /www/server/data
skip-external-locking
performance_schema_max_table_instances=400
table_definition_cache=400
key_buffer_size = 512M
max_allowed_packet = 100G
table_open_cache = 1024
sort_buffer_size = 2048K
net_buffer_length = 8K
read_buffer_size = 2048K
read_rnd_buffer_size = 1024K
myisam_sort_buffer_size = 64M
thread_cache_size = 192
query_cache_size = 0M
tmp_table_size = 1024M
explicit_defaults_for_timestamp = true
#skip-networking
skip-name-resolve
skip-grant-tables
max_connections = 2800
max_connect_errors = 100
open_files_limit = 65535
sql-mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES
#log-bin=mysql-bin
#binlog_format=mixed
server-id = 1
expire_logs_days = 10
slow_query_log=1
slow-query-log-file=/www/server/data/mysql-slow.log
long_query_time=3
back_log = 900
#log_queries_not_using_indexes=on
#loose-innodb-trx=0
#loose-innodb-locks=0
#loose-innodb-lock-waits=0
#loose-innodb-cmp=0
#loose-innodb-cmp-per-index=0
#loose-innodb-cmp-per-index-reset=0
#loose-innodb-cmp-reset=0
#loose-innodb-cmpmem=0
#loose-innodb-cmpmem-reset=0
#loose-innodb-buffer-page=0
#loose-innodb-buffer-page-lru=0
#loose-innodb-buffer-pool-stats=0
#loose-innodb-metrics=0
#loose-innodb-ft-default-stopword=0
#loose-innodb-ft-inserted=0
#loose-innodb-ft-deleted=0
#loose-innodb-ft-being-deleted=0
#loose-innodb-ft-config=0
#loose-innodb-ft-index-cache=0
#loose-innodb-ft-index-table=0
#loose-innodb-sys-tables=0
#loose-innodb-sys-tablestats=0
#loose-innodb-sys-indexes=0
#loose-innodb-sys-columns=0
#loose-innodb-sys-fields=0
#loose-innodb-sys-foreign=0
#loose-innodb-sys-foreign-cols=0
default_storage_engine = InnoDB
innodb_data_home_dir = /www/server/data
innodb_data_file_path = ibdata1:10M:autoextend
innodb_log_group_home_dir = /www/server/data
innodb_buffer_pool_size = 1024M
innodb_log_file_size = 512M
innodb_log_buffer_size = 128M
innodb_flush_log_at_trx_commit = 1
innodb_lock_wait_timeout = 100
innodb_max_dirty_pages_pct = 90
innodb_read_io_threads = 16
innodb_write_io_threads = 16
[mysqldump]
quick
max_allowed_packet = 16M
[mysql]
no-auto-rehash
[myisamchk]
key_buffer_size = 256M
sort_buffer_size = 4M
read_buffer = 2M
write_buffer = 2M
[mysqlhotcopy]
interactive-timeout
一旦并发量有点大，可能会有一个查询阻塞，就会造成链接不上数据库或者php报错：
connect() to unix:/tmp/php-cgi-56.sock failed (11: Resource temporarily unavailable) while connecting to upstream, client:
，问题应该在于数据库这边，数据库是独立的服务器，web有web的服务器，访问走的内网，不占用带宽。
