A large number of queries often appear 502 bad Gateway, how to handle

A large number of queries often appear 502 bad Gateway
Millions of data were checked directly Nginx 502 bad gateway. Another server is good. I cannot log on to the server to view the configuration. Ask you to get nginx+php comrades. What are the settings of your server? I sent it to the hardware department.
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502 is usually the php-fpm of the meal. This may be due to an excessive number of FPM connections or a longer program execution time.
However, you have a sentence to check the millions of data directly Nginx 502 Bad gateway. lightly, no one can do the remedy.
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Insufficient memory, a high number of connections, and a full CPU to handle new connections in a timely manner can cause this 502
That's exactly what you're saying.
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Your technical department is too food! Check millions of data at a time.
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I this refresh time also appeared 502, also nginx+php,, configuration of the time Nginx inside also has set: Access time (below) and so on several parameters to set the time of these several parameters longer, another may be you in Nginx build time resources may not be enough, hope you have help!
I just happen to have this happen occasionally, let ops restart the service.

Fastcgi_buffer_size 128k;
Fastcgi_buffers 8 128k;
Fastcgi_busy_buffers_size 128k;
Fastcgi_temp_file_write_size 128k;
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PHP slow, nginx request half a day not to respond, nature will time out. See if there is a timeout configuration, about fastcgi

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