ajp_buffer_size
The `ajp_buffer_size` directive sets the buffer size for reading the initial part of a response received from an AJP server.
Description
The ajp_buffer_size directive is crucial for optimizing the handling of responses made via the AJP (Apache JServ Protocol) in NGINX. This directive specifies the size of the buffer used to read the first part of the response from the AJP server, which typically contains the HTTP headers. Effectively, this allows NGINX to efficiently manage how much data to read initially, reducing latency and improving the performance of applications that utilize AJP. By setting this buffer size, you have control over the memory allocation for handling headers, ensuring that the size is appropriate for the expected headers in your specific use case.
The parameter for ajp_buffer_size accepts a size value, which can be defined in bytes (e.g., 1k, 2m) or in default page sizes of your system (like 4k, 8k). The default behavior is to match the size of the buffers set by the ajp_buffers directive, which means that if you do not set ajp_buffer_size, it will inherit that size. However, you can customize this value to be less than or equal to the buffer size if smaller headers are anticipated, which can optimize memory usage in scenarios where extensive AJP headers are not necessary.
Config Example
http {
upstream tomcats {
server 127.0.0.1:8009;
keepalive 10;
}
server {
listen 80;
location / {
ajp_buffer_size 2k;
ajp_pass tomcats;
}
}
}Setting the ajp_buffer_size too small may lead to truncated responses if the headers exceed the specified size.
If using improperly sized buffers, performance can degrade due to increased memory allocation overhead.
Make sure the size specified aligns with the expected response sizes from your AJP server.