Lots of us may find that our Eclipse takes a long time to launch, remember how many times you want to close this heavy machine and shout "F**K". Do you know why Eclipse launches slowly? Is it because we have too many plugins installed or we have created too many projects? No, it's not. Sometimes, it's because we don't have the correct configuration. So where to start? Go to eclipse.ini.First, you may want to add below line in your eclipse.ini configuration file:-Xloggc:gc.logThis is to show what Eclipse has done while launching.Next we can start to do some optimization. Here we take one exampl...

1. Use DocumentFragment or innerHTML to replace complex elements insertionDOM operation on browser is expensive. Although browser performance is improved much, multiple DOM elements insertion is still expensive and will affect the page load speed.Assume we have an ul element on our page, we now want to retrieve a JSON list using AJAX and then update the ul using JavaScript. Usually we may write it as :var list = document.querySelector('ul'); ajaxResult.items.forEach(function(item) { // Create element var li = document.createElement('li'); li.innerHTML = item.text; // Manipulate ...

"The well-designed functions are often relatively small, large function design is often a mess or there is a lot of room for optimization."Maybe you think there is no need to discuss the size of functions, because the nature of the function design is cohesive, its size is only its manifestations. But it is necessary to discuss about the size of function because the statement above .First let's understand the concept of minimum code processing unit : a basic operation (assignment, comparison, etc.) or a function call is seen as a minimum processing unit. The reasonable number of minimum process...

In some situations, MySQL will just use an index to fulfill the requirement of an ORDER BY or GROUP BY statement without extra sorting.Although ORDER BY will not have the exact match with index, index can still be used as long as the portion that is not included in the index is included in the where clause.The following queries will all use index to process the ORDER BY or GROUP BY part:SELECT * FROM t1 ORDER BY key_part1,key_part2,... ;SELECT * FROM t1 WHERE key_part1=constant ORDER BY key_part2;SELECT * FROM t1 WHERE key_part1=constant GROUP BY key_part2;SELECT * FROM t1 ORDER BY key_part1 D...

There is a question on Quora : Why doesn't Quora show interesting questions/answers on their landing page? Why is it this?not this?Quora's product manage gives his answer to this question, it's agreed by many users in this community. Here is his answer:The logged out homepage is pretty sparse now mostly because it hasn't been given much treatment since the initial product launch. But we have plans on redesigning it and testing different variations (some with less info on the page, some with more). The goal of the homepage though is to drive the highest volume of signups. Typically what I'...

For a big data system, one problem is the data access efficiency, one more problem is that the data insertion is very slow. We had a service system, the data loading process would take 4-5 hours. This time consuming operation is risky since if the program is interrupted during the loading process, it might be rerun, this will be troublesome. So it's necessary to improve the insertion efficiency for big data systems.Here we provide two optimization suggestions.1. Combine multiple insert statementCommon insert statement use is:INSERT INTO `insert_table` (`datetime`, `uid`,&nb...

In one of my current javascript projects, I have to deal with 3D voxel coordinates. And, sometimes, I have floating points coordinates which must be converted to integers in order to convert them into proper array index.Javascript is a wonderful language, really. However, implementations are sometimes weird, and the way to do something can sometimes have very huge impacts on the performances. Worse, sometimes the classical way is more expensive than the tricky one.So, some people have made performance comparisons on jsperf to check which is the fastest way to do. Most of these tests sa...

Looking at things through a microscopesometimes leads to surprising discoveriesObviously this is an utterly preposterous statement: it’s hard to think of a more ridiculous and esoteric coding requirement. I can just imagine all sorts of amusing conversations with designers and business sponsors: “No… the size of this <input> field should be 23… 24 is just too long!” Or: “We need to explain to users that their subject lines should be less than 23 letters…” Or: “Twitter got it all wrong… the 140 limit should have been 23!â€...