{"id":611,"date":"2009-11-25T23:09:06","date_gmt":"2009-11-25T15:09:06","guid":{"rendered":"http:\/\/blog.lolyco.com\/sean\/?p=611"},"modified":"2009-11-26T11:17:38","modified_gmt":"2009-11-26T03:17:38","slug":"ab-apache-bench-hanging-with-k-keep-alive-switch","status":"publish","type":"post","link":"https:\/\/blog.lolyco.com\/sean\/2009\/11\/25\/ab-apache-bench-hanging-with-k-keep-alive-switch\/","title":{"rendered":"Ab – Apache Bench hanging with -k Keep-Alive switch"},"content":{"rendered":"

This problem was making me go blind! I’m testing Spinneret with ab at the moment, trying to make sure there’s no disastrous behaviour under load. I found that ab just stopped after the first request if I used the -k switch. I’m not sure the problem is my fault, exactly, but I have ‘solved’ it. HTTP 1.0 didn’t have persistent connections. In HTTP 1.1, the default<\/em> behaviour is persistence, so only a mechanism for explicitly closing a connection is provided.<\/p>\n

\n

\"My<\/a>

My Spider<\/p><\/div>\n

Apache bench offers the ‘-k’ switch to allow you to test your webserver with persistent connections, but sends a HTTP\/1.0 request. The -k switch causes ab to send the header “Connection: Keep-Alive” to the server. Spinneret’s debugging log confirmed a response was sent back, and the ‘-v’ switch (verbose) in ab would even show that it received the response, but it would just ‘hang’ at that point, until it timed out:<\/p>\n

LOG: Response code = 200
\napr_poll: The timeout specified has expired (70007)<\/code><\/p>\n

I wasted a lot of time imagining what could be wrong with it before I decided to just duplicate the response from an Apache server that worked with the -k switch in ab. I spotted that Apache was returning the ‘Connection: Keep-Alive’ header. Adding that header field to a Spinneret response to a HTTP\/1.0 request that contains it solves the problem with ab.<\/p>\n

This behaviour isn’t specified anywhere, but it is suggested in an Internet Draft for HTTP\/1.1 at w3.org<\/a>:<\/p>\n

The Connection<\/code> header field with a keep-alive keyword must be sent on all requests and responses that wish to continue the persistence.<\/p><\/blockquote>\n

Perhaps the nice people at Apache might consider some less baffling behaviour for when amateur webserver programmers attempt to pick up their tools!<\/p>\n","protected":false},"excerpt":{"rendered":"

This problem was making me go blind! I’m testing Spinneret with ab at the moment, trying to make sure there’s no disastrous behaviour under load. I found that ab just stopped after the first request if I used the -k switch. I’m not sure the problem is my fault, exactly, but I have ‘solved’ it. […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[14,20,50,3,45],"tags":[24,107,109,41,19,9,18,105,57],"class_list":["post-611","post","type-post","status-publish","format-standard","hentry","category-broken","category-fixed","category-foss","category-software","category-spinneret","tag-apache","tag-broken","tag-fixed","tag-http","tag-malaysia","tag-open-source","tag-server","tag-software","tag-web"],"_links":{"self":[{"href":"https:\/\/blog.lolyco.com\/sean\/wp-json\/wp\/v2\/posts\/611","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.lolyco.com\/sean\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.lolyco.com\/sean\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.lolyco.com\/sean\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.lolyco.com\/sean\/wp-json\/wp\/v2\/comments?post=611"}],"version-history":[{"count":6,"href":"https:\/\/blog.lolyco.com\/sean\/wp-json\/wp\/v2\/posts\/611\/revisions"}],"predecessor-version":[{"id":615,"href":"https:\/\/blog.lolyco.com\/sean\/wp-json\/wp\/v2\/posts\/611\/revisions\/615"}],"wp:attachment":[{"href":"https:\/\/blog.lolyco.com\/sean\/wp-json\/wp\/v2\/media?parent=611"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.lolyco.com\/sean\/wp-json\/wp\/v2\/categories?post=611"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.lolyco.com\/sean\/wp-json\/wp\/v2\/tags?post=611"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}