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Redis 有很多客户端

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Redis 有很多客户端

我们的服务器中的 Redis 出现了问题。

首先在 PHP 脚本中我们通过tcp:127.0.0.1:6379端口连接到 Redis 进行缓存。在这种情况下，使用netstat -anp |grep 6379 |wc -l命令我们有大约 57000 个连接，但 PHP 无法连接到 Redis。

之后我们改为tcp连接unixsocket。一切看起来都很好，直到我们发现 Redis 有很多理想的客户端连接。

client list下面你可以看到redis 上的命令输出：

    id=4369214 addr=/tmp/redis.sock:0 fd=953 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369215 addr=/tmp/redis.sock:0 fd=955 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369216 addr=/tmp/redis.sock:0 fd=1045 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369217 addr=/tmp/redis.sock:0 fd=1056 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369218 addr=/tmp/redis.sock:0 fd=1108 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369219 addr=/tmp/redis.sock:0 fd=1109 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369220 addr=/tmp/redis.sock:0 fd=1110 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369221 addr=/tmp/redis.sock:0 fd=1112 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369222 addr=/tmp/redis.sock:0 fd=1113 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369223 addr=/tmp/redis.sock:0 fd=1114 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369224 addr=/tmp/redis.sock:0 fd=1115 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369225 addr=/tmp/redis.sock:0 fd=1116 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369226 addr=/tmp/redis.sock:0 fd=1117 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369227 addr=/tmp/redis.sock:0 fd=1118 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369228 addr=/tmp/redis.sock:0 fd=1119 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369229 addr=/tmp/redis.sock:0 fd=1120 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369230 addr=/tmp/redis.sock:0 fd=1121 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369231 addr=/tmp/redis.sock:0 fd=1122 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369232 addr=/tmp/redis.sock:0 fd=1123 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369233 addr=/tmp/redis.sock:0 fd=1124 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369234 addr=/tmp/redis.sock:0 fd=1125 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369235 addr=/tmp/redis.sock:0 fd=1126 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369236 addr=/tmp/redis.sock:0 fd=1127 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369237 addr=/tmp/redis.sock:0 fd=1128 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369238 addr=/tmp/redis.sock:0 fd=1129 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369239 addr=/tmp/redis.sock:0 fd=1130 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369240 addr=/tmp/redis.sock:0 fd=1131 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369241 addr=/tmp/redis.sock:0 fd=1132 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369242 addr=/tmp/redis.sock:0 fd=1133 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369243 addr=/tmp/redis.sock:0 fd=1134 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369244 addr=/tmp/redis.sock:0 fd=1135 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
    id=4369245 addr=/tmp/redis.sock:0 fd=1136 name= age=0 idle=0 flags=U db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=NULL
...

输出结果info clients为：

# Clients
connected_clients:917
client_longest_output_list:2
client_biggest_input_buf:0
blocked_clients:0

我们的杯子使用率很高，而且 Redis 很慢。即使在禁用缓存之后，我们仍然存在这个问题。

谢谢

答案1

Redis 的配置中有超时功能。使用以下方法动态设置超时：

 config set timeout <valid value in seconds>

如果 Redis 空闲了配置的时间，它会关闭连接。出现此问题是因为您的 PHP 脚本在请求结束时没有关闭 redis 套接字。我认为 redis 的速度变慢是因为它达到了打开文件描述符的限制

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