Nginx 處理的每個(gè)請(qǐng)求均有相應(yīng)的超時(shí)設(shè)置。如果做好這些超時(shí)時(shí)間的限定，判定超時(shí)后資源被釋放，用來(lái)處理其他的請(qǐng)求，以此提升 Nginx 的性能。

keepalive_timeout

HTTP 是一種無(wú)狀態(tài)協(xié)議，客戶(hù)端向服務(wù)器發(fā)送一個(gè) TCP 請(qǐng)求，服務(wù)端響應(yīng)完畢后斷開(kāi)連接。

如果客戶(hù)端向服務(wù)器發(fā)送多個(gè)請(qǐng)求，每個(gè)請(qǐng)求都要建立各自獨(dú)立的連接以傳輸數(shù)據(jù)。

HTTP 有一個(gè) KeepAlive 模式，它告訴 webserver 在處理完一個(gè)請(qǐng)求后保持這個(gè) TCP 連接的打開(kāi)狀態(tài)。若接收到來(lái)自客戶(hù)端的其它請(qǐng)求，服務(wù)端會(huì)利用這個(gè)未被關(guān)閉的連接，而不需要再建立一個(gè)連接。
KeepAlive 在一段時(shí)間內(nèi)保持打開(kāi)狀態(tài)，它們會(huì)在這段時(shí)間內(nèi)占用資源。占用過(guò)多就會(huì)影響性能。

Nginx 使用 keepalive_timeout 來(lái)指定 KeepAlive 的超時(shí)時(shí)間（timeout）。指定每個(gè) TCP 連接最多可以保持多長(zhǎng)時(shí)間。Nginx 的默認(rèn)值是 75 秒，有些瀏覽器最多只保持 60 秒，所以可以設(shè)定為 60 秒。若將它設(shè)置為 0，就禁止了 keepalive 連接。

# 配置段: http, server, location
keepalive_timeout 60s;

client_body_timeout

指定客戶(hù)端與服務(wù)端建立連接后發(fā)送 request body 的超時(shí)時(shí)間。如果客戶(hù)端在指定時(shí)間內(nèi)沒(méi)有發(fā)送任何內(nèi)容，Nginx 返回 HTTP 408（Request Timed Out）。

# 配置段: http, server, location
client_body_timeout 20s;

client_header_timeout

客戶(hù)端向服務(wù)端發(fā)送一個(gè)完整的 request header 的超時(shí)時(shí)間。如果客戶(hù)端在指定時(shí)間內(nèi)沒(méi)有發(fā)送一個(gè)完整的 request header，Nginx 返回 HTTP 408（Request Timed Out）。

# 配置段: http, server, location

client_header_timeout 10s;

send_timeout

服務(wù)端向客戶(hù)端傳輸數(shù)據(jù)的超時(shí)時(shí)間。

# 配置段: http, server, location

send_timeout 30s;

客戶(hù)度連接nginx超時(shí), 建議5s內(nèi)

接收客戶(hù)端header超時(shí), 默認(rèn)60s, 如果60s內(nèi)沒(méi)有收到完整的http包頭, 返回408

Syntax: client_header_timeout time;
Default:?
client_header_timeout 60s;
Context: ?http, server
Defines a timeout for reading client request header. If a client does not transmit the entire header within this time,
the 408 (Request Time-out) error is returned to the client.

接收客戶(hù)端body超時(shí), 默認(rèn)60s, 如果連續(xù)的60s內(nèi)沒(méi)有收到客戶(hù)端的1個(gè)字節(jié), 返回408

Syntax: client_body_timeout time;
client_body_timeout 60s;
Context: ?http, server, location
Defines a timeout for reading client request body. The timeout is set only for a period between two successive read operations, not for the transmission of the whole request body.
If a client does not transmit anything within this time,the 408 (Request Time-out) error is returned to the client.

keepalive時(shí)間，默認(rèn)75s，通常keepalive_timeout應(yīng)該比client_body_timeout大

Syntax: keepalive_timeout timeout [header_timeout];
Default:?
keepalive_timeout 75s;
Context: ?http, server, location
The first parameter sets a timeout during which a keep-alive client connection will stay open on the server side. The zero value disables keep-alive client connections.
The optional second parameter sets a value in the “Keep-Alive: timeout=time” response header field. Two parameters may differ.

The “Keep-Alive: timeout=time” header field is recognized by Mozilla and Konqueror. MSIE closes keep-alive connections by itself in about 60 seconds.

可以理解為T(mén)CP連接關(guān)閉時(shí)的SO_LINGER延時(shí)設(shè)置，默認(rèn)5s

Syntax: lingering_timeout time;
lingering_timeout 5s;
When lingering_close is in effect, this directive specifies the maximum waiting time for more client data to arrive. If data are not received during this time,
the connection is closed. Otherwise, the data are read and ignored, and nginx starts waiting for more data again.
The “wait-read-ignore” cycle is repeated, but no longer than specified by the lingering_time directive.

域名解析超時(shí)，默認(rèn)30s

Syntax: resolver_timeout time;
resolver_timeout 30s;
Sets a timeout for name resolution, for example:
resolver_timeout 5s;

發(fā)送數(shù)據(jù)至客戶(hù)端超時(shí), 默認(rèn)60s, 如果連續(xù)的60s內(nèi)客戶(hù)端沒(méi)有收到1個(gè)字節(jié), 連接關(guān)閉

Syntax: send_timeout time;
send_timeout 60s;
Sets a timeout for transmitting a response to the client. The timeout is set only between two successive write operations,
not for the transmission of the whole response. If the client does not receive anything within this time, the connection is closed.

nginx與upstream server的連接超時(shí)時(shí)間

Syntax: proxy_connect_timeout time;
proxy_connect_timeout 60s;
Defines a timeout for establishing a connection with a proxied server. It should be noted that this timeout cannot usually exceed 75 seconds.

nginx接收upstream server數(shù)據(jù)超時(shí), 默認(rèn)60s, 如果連續(xù)的60s內(nèi)沒(méi)有收到1個(gè)字節(jié), 連接關(guān)閉

Syntax: proxy_read_timeout time;
proxy_read_timeout 60s;
Defines a timeout for reading a response from the proxied server. The timeout is set only between two successive read operations,
not for the transmission of the whole response. If the proxied server does not transmit anything within this time, the connection is closed.

nginx發(fā)送數(shù)據(jù)至upstream server超時(shí), 默認(rèn)60s, 如果連續(xù)的60s內(nèi)沒(méi)有發(fā)送1個(gè)字節(jié), 連接關(guān)閉

Syntax: proxy_send_timeout time;
proxy_send_timeout 60s;
Sets a timeout for transmitting a request to the proxied server. The timeout is set only between two successive write operations,
not for the transmission of the whole request. If the proxied server does not receive anything within this time, the connection is closed.