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PostgreSQL error: Fatal: role “username” does not exist
I'm setting up my PostgreSQL 9.1. I can't do anything with PostgreSQL: can't createdb , can't createuser ; all operations return the error message
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EC2 instance has no public DNS
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How does doing this effect the instances that already have a Public DNS?
– kraftydevil
Apr 6 '16 at 17:07
5
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How expensive is the lock statement?
...ing with multi threading and parallel processing and I needed a counter to do some basic counting and statistic analysis of the speed of the processing. To avoid problems with concurrent use of my class I've used a lock statement on a private variable in my class:
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Most efficient way to determine if a Lua table is empty (contains no entries)?
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Why do we gain speed by doing local next?
– Moberg
Oct 2 '16 at 20:22
2
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Best way to give a variable a default value (simulate Perl ||, ||= )
I love doing this sort of thing in Perl: $foo = $bar || $baz to assign $baz to $foo if $bar is empty or undefined. You also have $foo ||= $bletch which will only assign $bletch to $foo if $foo is not defined or empty.
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SQL Server - Create a copy of a database table and place it in the same database?
...ate copies of ABC with names ABC_1, ABC_2, ABC_3 in the same DB. How can I do that using either Management Studio (preferably) or SQL queries ?
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Select N random elements from a List in C#
I need a quick algorithm to select 5 random elements from a generic list. For example, I'd like to get 5 random elements from a List<string> .
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Getting output of system() calls in Ruby
If I call a command using Kernel#system in Ruby, how do I get its output?
15 Answers
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Why should you remove unnecessary C# using directives?
...t of extension methods shown)
What removing the unused namespaces won't do:
alter in any way the output of the compiler.
alter in any way the execution of the compiled program (faster loading, or better performance).
The resulting assembly is the same with or without unused using(s) removed....
Handling applicationDidBecomeActive - “How can a view controller respond to the app becoming Active?
...on gets sent to your application.
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(someMethod:)
name:UIApplicationDidBecomeActiveNotification object:nil];
Don't forget to clean up after ...