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Redis 有很多客戶

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Redis 有很多客戶

我們的伺服器中的 Redis 出現問題。

首先在 PHP 腳本中，我們透過tcp:127.0.0.1:6379連接埠連接到 Redis 進行快取。在這種情況下，使用netstat -anp |grep 6379 |wc -l指令我們有大約 57000 個連接，PHP 無法連接到 Redis。

之後我們改為tcp連線unixsocket。一切看起來都很好，直到我們發現 Redis 有很多理想的客戶端連線。

下面你可以看到client listredis 上指令的輸出：

    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
...

的輸出info clients將是：

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

我們的cup使用率很高，而Redis很慢。即使我們禁用快取後，我們仍然遇到這個問題。

謝謝

答案1

Redis 的配置中有逾時。使用動態設定逾時

 config set timeout <valid value in seconds>

如果連線在設定的時間內處於空閒狀態，Redis 將關閉連線。發生此問題的原因是您的 PHP 腳本未在請求結束時關閉 Redis 套接字。我認為 redis 速度變慢，因為它達到了開啟檔案描述符限制

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