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What is a “Bitmap heap scan” in a query plan?
... stay in memory, but you get the point).
A bitmap index scan will sequentially open a short-list of disk pages, and grab every applicable row in each one (hence the so-called recheck cond you see in query plans).
Note, as an aside, how clustering/row order affects the associated costs with either ...
Checking if a key exists in a JavaScript object?
... testing whether a key exists. What if the key exists but the value is actually undefined?
var obj = { key: undefined };
obj["key"] !== undefined // false, but the key exists!
You should instead use the in operator:
"key" in obj // true, regardless of the actual value
If you want to check if a...
What is the use of hashCode in Java?
...
Buckets aside, hashcode is a method that the object calls to determine the order to store each object in memory. If objects are equal, then their hashcode must also be equal. (converse of this statement is false)
– NoName
Jun 24 '17 at 6:1...
Why are empty catch blocks a bad idea? [closed]
...-catch , which people (including Jon Skeet) say empty catch blocks are a really bad idea? Why this? Is there no situation where an empty catch is not a wrong design decision?
...
How to “re-run with -deprecation for details” in sbt?
...
> compile
> exit
Due to in ThisBuild, set applies the settings to all sub-projects, as well.
Command Line
You could also run the above as a single command on command line.
sbt '; set scalacOptions in ThisBuild ++= Seq("-unchecked", "-deprecation") ; compile'
The trick is to use ; (sem...
Security of REST authentication schemes
...s answer only mentioned SSL in the context of data transfer and didn't actually cover authentication.
You're really asking about securely authenticating REST API clients. Unless you're using TLS client authentication, SSL alone is NOT a viable authentication mechanism for a REST API. SSL without ...
RSpec controller testing - blank response.body
...with a problem when testing my controllers with RSpec - the response.body call always returns an empty string. In browser everything renders correctly, and cucumber feature tests seem to get it right, but RSpec fails each and every time.
...
Capturing “Delete” Keypress with jQuery
...ntable) characters. keydown is handled at a lower level so it will capture all nonprinting keys like delete and enter.
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JavaScript: How to find out if the user browser is Chrome?
...perties for the 'window object'. When you collapse the object you can view all the properties, including the 'chrome' property.
You can't use strictly equals true anymore to check in IE for window.chrome. IE used to return undefined, now it returns true. But guess what, IE11 now returns undefined ...
Encoding Javascript Object to Json string
...e looking for.
var json = JSON.stringify(new_tweets);
You can also do it all at once:
var new_tweets = {
k: {
tweet_id: 98745521,
user_id: 54875,
data: {
in_reply_to_screen_name: 'other_user',
text: 'tweet_text'
}
}
}
...