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Why does PostgreSQL perform sequential scan on indexed column?
...ster than an index scan.
This is because an index scan requires several IO operations for each row (look up the row in the index, then retrieve the row from the heap). Whereas a sequential scan only requires a single IO for each row - or even less because a block (page) on the disk contains more...
Why are Docker container images so large?
...ependencies your installed software has.
I was able to make your installation significantly smaller by adding yum -y clean all to each line:
FROM fedora:latest
RUN yum -y install nano && yum -y clean all
RUN yum -y install git && yum -y clean all
It is important to do that for ea...
How to read a large file - line by line?
...with statement handles opening and closing the file, including if an exception is raised in the inner block. The for line in f treats the file object f as an iterable, which automatically uses buffered I/O and memory management so you don't have to worry about large files.
There should be one --...
Redefining NULL
...L pointer will remain undetected and at the same time cause dangerous behaviour.
7 Answers
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Xcode 4 and Core Data: How to enable SQL Debugging
I'm working on a universal iOS app and I'd like to see the raw SQL in the logs when I'm debugging. There is some info in this blog post about how to enable raw SQL logging for iOS Core Data development. The given example is for Xcode 3 and it's just not clear to me how to enable this in Xcode 4.
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C# using streams
Streams are kind of mysterious to me. I don't know when to use which stream and how to use them. Can someone explain to me how streams are used?
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Create a shortcut on Desktop
...
With additional options such as hotkey, description etc.
At first, Project > Add Reference > COM > Windows Script Host Object Model.
using IWshRuntimeLibrary;
private void CreateShortcut()
{
object shDesktop = (object)"De...
Why aren't variables declared in “try” in scope in “catch” or “finally”?
...
Two things:
Generally, Java has just 2 levels of scope: global and function. But, try/catch is an exception (no pun intended). When an exception is thrown and the exception object gets a variable assigned to it, that object variable is only available within the "catch" section and is destroyed ...
Clear android application user data
Using adb shell to clear application data
7 Answers
7
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Idiomatic way to convert an InputStream to a String in Scala
I have a handy function that I've used in Java for converting an InputStream to a String. Here is a direct translation to Scala:
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