Twitter engineer Dustin Diaz says NewTwitter has some major slowness due to jQuery

This is not the first time people have problem caused by switching to newest version of jQuery. Dustin Diaz, engineer at Twitter tweeted, “Turns out #NewTwitter has some major slowness due to upgrading from jQuery 1.4.2 to 1.4.4 – We will be downgrading.” Dustin Diaz’s further comments might prove useful to others working with JQuery.

• The scrolling was the worst issue and we’ll be moving away from a scroll event to a simple timed dispatcher.
• “@Stormchild yep. one of our engineers noted that it had a major regression in Sizzle (the selector engine) performance”
• @JoshStodola we always test. it passed all our selenium and unit tests without failure, but we are currently formulating new speed metrics
• @timhaines yes. it was a major factor. we are however taking even further steps into making the app faster.
• @adski there was a major regression in Sizzle, and we calculate the height of the document on scroll – an expensive operation gone wrong