Got an e-mail from Kevin Burton of TailRank this weekend saying that he had found some issue with the system’s infrastructure and that he should be back to normal performance.
Looking at this graph, I agree with him.
Technorati Tags: GrabPERF, Web performance, TailRank
I was trying yesterday to debug an issue that was appeared to be affecting the PubSub Agent — yes, I re-started it at the request of their sysadmin.
The issue was that it was showing data that appeared to have no relationship with the data appearing from all of the other measurement locations. I tried blocking it off using IPTables, MySQL restrictions, etc.
This afternoon, I figured out the problem.
Yesterday, I had been using this query to diagnose the problem:
select
*
from
data
where
agent_id = 11
and date between subdate(now(),interval 30 minute) and now()
order by
date DESC
And everytime I looked, there was new data. I couldn’t seem to stop the agent from delivering data. Then I had a flash.
select
count(*)
from
data
where
agent_id = 11
and date > now()
157,000 rows of data. From the future.
Thankfully I know the guy who is responsible for keeping the PubSub servers running, and he is going to adjust the time, etc. But he makes no promises about how long the agent machine will stay running.
I apologize for the bad data.
Technorati Tags: GrabPERF, PubSub, Web Performance, The Future
I took the big leap today and upgraded the base Web server to Apache 2.2.3. This required some finagling with httpd.conf file, and a re-build of PHP, but once that was done, the app bounced up happy as a clam.
As usual, let me know if you see anything unusual — with the server, not with the author.
Technorati Tags: Apache, Apache 2.2.3, PHP
This morning’s bounty of posts brought in two that will make you think.
First was Port80 Software’s comments on using the Cache-Control mechanism embedded in all browsers. This is interesting to read, as I have been trying to get companies to use this mechanism more intelligently for a number of years. I know that the Port80 team gets it, but it is always nice to have some outside validation of a position you have tried to evangelize for a long time.
The second was Tim O’Reilly’s post on Cal Henderson’s new book on Web scalability. While I am likely to purchase the book for a professional interest, I have one problem with Flickr’s current configuration: static.flickr.com does not use HTTP persistence, something I noted last week. This strikes me as weird.
It’s always good to see Web performance rear its head.
Technorati Tags: Tim O’reilly, Cal Henderson, Cache-Control, http, port80 software, persistent connections, Flickr