Skip to main content

IE browsing slowness and mod_ssl

We were observing that our pages were loading very slow in IE compared to FF and we thought that IE is inherently slow parsing the page, that was a wrong assumption. Using fiddler with IE shows that the server somehow was making too many SSL handshakes with server compared to when we plugged in Fiddler with FF or Safari. This was traced down to an Apache configuration.

Apache comes with a default mod_ssl conf

SetEnvIf User-Agent ".*MSIE.*" \
nokeepalive ssl-unclean-shutdown \
downgrade-1.0 force-response-1.0


What this tells is that for  all IE browsers dont use Keep-alive and downgrade HTTP response to 1.0. Apache was consuming significant time doing this when compared to  same request in FF. Well all this was required for really old browsers.


Changing the conf as shown below solved the issue and now we get good initial load performance in IE browsers


SetEnvIf User-Agent ".*MSIE [1-4].*" \
nokeepalive ssl-unclean-shutdown \
downgrade-1.0 force-response-1.0

SetEnvIf User-Agent ".*MSIE [5-9].*" \
ssl-unclean-shutdown
Labels:

Comments

  1. AnonymousApril 15, 2011 at 1:25 PM

    ".*MSIE [1-4].*" should be ".*MSIE [1-4]\..*" now that IE 10 is coming up...

    ReplyDelete

Post a Comment

Popular posts from this blog

Killing a particular Tomcat thread

Update: This JSP does not work on a thread that is inside some native code.  On many occasions I had a thread stuck in JNI code and it wont work. Also in some cases thread.stop can cause jvm to hang. According to javadocs " This method is inherently unsafe. Stopping a thread with Thread.stop causes it to unlock all of the monitors that it has locked". I have used it only in some rare occasions where I wanted to avoid a system shutdown and in some cases we ended up doing system shutdown as jvm was hung so I had a 70-80% success with it.   -------------------------------------------------------------------------------------------------------------------------- We had an interesting requirement. A tomcat thread that was spawned from an ExecutorService ThreadPool had gone Rogue and was causing lots of disk churning issues. We cant bring down the production server as that would involve downtime. Killing this thread was harmless but how to kill it, t
6 comments
Read more

Adding Jitter to cache layer

Thundering herd is an issue common to webapp that rely on heavy caching where if lots of items expire at the same time due to a server restart or temporal event, then suddenly lots of calls will go to database at same time. This can even bring down the database in extreme cases. I wont go into much detail but the app need to do two things solve this issue. 1) Add consistent hashing to cache layer : This way when a memcache server is added/removed from the pool, entire cache is not invalidated.  We use memcahe from both python and Java layer and I still have to find a consistent caching solution that is portable across both languages. hash_ring and spymemcached both use different points for server so need to read/test more. 2) Add a jitter to cache or randomise the expiry time: We expire long term cache  records every 8 hours after that key was added and short term cache expiry is 2 hours. As our customers usually comes to work in morning and access the cloud file server it can happe
Post a Comment
Read more

Preparing for an interview after being employed 11 years at a startup

I would say I didn't prepared a hell lot but  I did 2 hours in night every day and every weekend around 8 hours for 2-3 months. I did 20-30 leetcode medium problems from this list https://leetcode.com/explore/interview/card/top-interview-questions-medium/.  I watched the first 12 videos of Lecture Videos | Introduction to Algorithms | Electrical Engineering and Computer Science | MIT OpenCourseWare I did this course https://www.educative.io/courses/grokking-the-system-design-interview I researched on topics from https://www.educative.io/courses/java-multithreading-for-senior-engineering-interviews and leetcode had around 10 multithreading questions so I did those I watched some 10-20 videos from this channel https://www.youtube.com/channel/UCn1XnDWhsLS5URXTi5wtFTA 
Post a Comment
Read more