Skip to main content

Pagespeed and cache flush

Ran into an issue where customers would complain that random logins are slow and then subsequent request are fast. Took a long time to debug because it was totally random.

Finally found that because we give each customer a unique subdomain like XXX.yyy.com page speed was caching the aggregated bundles per subdomain.  When we configure pagespeed we never configured the cache size so by default it was taking 100M.  Before we did Tomcat HA domains were pinned to a node so we never ran into the issue but after HA any customer can be served from any node so we were running into an issue where every hour the cache was flushed and domains would see this random login. 

Took almost 2-3 hours to debug the issue and the only reason I was able to figure out the issue because I was thinking like if I had to write pagespeed how would I write it. Also I  ran a du on the cache and it was 267M and luckily I saw the apache error logs that the cache clean had ran and ran du again and it was 97M.  I feel like accomplishing something today :).

Comments

Post a Comment

Popular posts from this blog

RabbitMQ java clients for beginners

Here is a sample of a consumer and producer example for RabbitMQ. The steps are Download Erlang Download Rabbit MQ Server Download Rabbit MQ Java client jars Compile and run the below two class and you are done. This sample create a Durable Exchange, Queue and a Message. You will have to start the consumer first before you start the for the first time. For more information on AMQP, Exchanges, Queues, read this excellent tutorial http://blogs.digitar.com/jjww/2009/01/rabbits-and-warrens/ +++++++++++++++++RabbitMQProducer.java+++++++++++++++++++++++++++ import com.rabbitmq.client.Connection; import com.rabbitmq.client.Channel; import com.rabbitmq.client.*; public class RabbitMQProducer { public static void main(String []args) throws Exception { ConnectionFactory factory = new ConnectionFactory(); factory.setUsername("guest"); factory.setPassword("guest"); factory.setVirtualHost("/"); factory.setHost("127.0.0.1"); factory.se...
23 comments
Read more

Jersey streaming binary data

In the previous post I showed how you can post binary data to a jersey REST api. You can also use Jersey to serve files, although its better done by apache or nginx but sometimes you might want to serve thumbnails stored in a database out of a service and put varnish in front of the REST api to cache the thumbnails. This is just a demonstration of using jersey to serve binary data in streaming fashion. @Path("/download-service") public class DownaloadService extends SecureRestService { private static final AppLogger logger = AppLogger.getLogger(DownaloadService.class); @POST @Produces(MediaType.APPLICATION_OCTET_STREAM) public StreamingOutput getThumbnail( @FormParam("securityKey") final String securityKey, @FormParam("guid") final String guid) throws JSONException { return new StreamingOutput() { @Override public void write(OutputStream out) throws IOException { try { if (!isAuthorized(securityKey)) { response.sendErro...
12 comments
Read more

Spring 3.2 quartz 2.1 Jobs added with no trigger must be durable.

I am trying to enable HA on nodes and in that process I found that in a two test node setup a job that has a frequency of 10 sec was running into deadlock. So I tried upgrading from Quartz 1.8 to 2.1 by following the migration guide but I ran into an exception that says "Jobs added with no trigger must be durable.". After looking into spring and Quartz code I figured out that now Quartz is more strict and earlier the scheduler.addJob had a replace parameter which if passed to true would skip the durable check, in latest quartz this is fixed but spring hasnt caught up to this. So what do you do, well I jsut inherited the factory and set durability to true and use that public class DurableJobDetailFactoryBean extends JobDetailFactoryBean {     public DurableJobDetailFactoryBean() {         setDurability(true);     } } and used this instead of JobDetailFactoryBean in the spring bean definition     <bean i...
7 comments
Read more