apache requests very slow after using ProxyPass
So I'm running Tomcat(8.0) behind Apache(2.4) on Windows Server 2012 and using ProxyPass to pass through all traffic. Everything works fine, but whenever I do nothing for 60 seconds, and then hit the server again, i get a 8-20 second delay, like apache is creating a new process to handle the request.
My configuration is pretty much the default that comes with Apache Haus, with the addition of the proxy stuff, which I believe is the culprit:
ProxyPass /static/ !
ProxyPass / http://localhost:8088/
ProxyPassReverse / http://localhost:8088/
I added the
/static/ !
exemption to see if same problem would happen on static files being served, and apparently it does. I further narrowed it down by commenting out all the ProxyPass stuff, and verifying my static file always loads fast. Then i uncommented ProxyPass stuff, and only requested my static file, and it again always returned fast. But once I hit a URL that takes me through the proxy, wait a minute, then hit it again, something goes horribly wrong. Below is network monitor output for two requests, first of the static file being requested a second time after a 1 minute delay before proxy use, the other after the proxy had been used twice with delay between proxy requests.
3501 4:17:48 PM 10/21/2015 104.2752287 httpd.exe HTTP HTTP:Request, GET /static/index.html
3502 4:17:48 PM 10/21/2015 104.2760830 httpd.exe HTTP HTTP:Response, HTTP/1.1, Status: Not modified, URL: /static/index.html
After (8 seconds to return):
24232 4:26:13 PM 10/21/2015 608.7355960 httpd.exe HTTP HTTP:Request, GET /static/index.html
24775 4:26:20 PM 10/21/2015 616.0896861 httpd.exe HTTP HTTP:Response, HTTP/1.1, Status: Not modified, URL: /static/index.html
I'm noticing more of this SynReTransmit line after it was initially broken, not sure if it's relevant:
24226 4:26:13 PM 10/21/2015 608.7286692 httpd.exe TCP TCP:[SynReTransmit #24107]Flags=......S., SrcPort=61726, DstPort=HTTP(80), PayloadLen=0, Seq=1157444168, Ack=0, Win=8192 ( Negotiating scale factor 0x2 ) = 8192
But basically every call, be it to static file or over proxy, if it's been over 60 seconds since the last call, will take forever to get a response!
Any ideas?
UPDATE: I was running a slightly older version of Apache, 2.4.12, but updating to latest, 2.4.17, didn't fix it. I've tried all sorts of keepalive settings, nothing seems to help. On another forum i was directed at this apache dev thread which has a proposed patch for what sounds like a similar issue, guess I'll wait for an apache update:
Answer
Try explicitly tuning the ProxyReceiveBufferSize:
# For increase throughput (bytes)
ProxyReceiveBufferSize 2048