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postgresql COUNT(DISTINCT …) very slow
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I found this thread on www.postgresql.org which discusses the same thing: link. One of the replies (by Jeff Janes) says that COUNT(DISTINCT()) sorts the table to do its work instead of using hash.
– Ankur
Dec ...
Node.js: Difference between req.query[] and req.params
....get('/hi/:param1', function(req,res){} );
and given this URL
http://www.google.com/hi/there?qs1=you&qs2=tube
You will have:
req.query
{
qs1: 'you',
qs2: 'tube'
}
req.params
{
param1: 'there'
}
Express req.params >>
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Java heap terminology: young, old and permanent generations?
... other?
Image source & oracle technetwork tutorial article: http://www.oracle.com/webfolder/technetwork/tutorials/obe/java/gc01/index.html
"The General Garbage Collection Process" in above article explains the interactions between them with many diagrams.
Have a look at summary diagram:
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How can I use threading in Python?
...2
from multiprocessing.dummy import Pool as ThreadPool
urls = [
'http://www.python.org',
'http://www.python.org/about/',
'http://www.onlamp.com/pub/a/python/2003/04/17/metaclasses.html',
'http://www.python.org/doc/',
'http://www.python.org/download/',
'http://www.python.org/getit/',
'...
Configuring Log4j Loggers Programmatically
...uring log4j2 programmatically in Java, then this link could help: (https://www.studytonight.com/post/log4j2-programmatic-configuration-in-java-class)
Here is the basic code for configuring a Console Appender:
ConfigurationBuilder<BuiltConfiguration> builder = ConfigurationBuilderFactory.newC...
What are the relationships between Any, AnyVal, AnyRef, Object and how do they map when used in Java
...this? The text of the page has some java interoperability remarks.
http://www.scala-lang.org/node/128
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Is div inside list allowed? [duplicate]
...t;
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<ti...
Is there a way to force ASP.NET Web API to return plain text?
...straightforward media type formatter that support text mime types.
http://www.asp.net/web-api/overview/formats-and-model-binding/media-formatters
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How to detect the device orientation using CSS media queries?
...tion:landscape) { … }
The CSS definition of a media query is at http://www.w3.org/TR/css3-mediaqueries/#orientation
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When should I use a table variable vs temporary table in sql server?
...e large then it hurts you bad.
My understanding is mostly based on http://www.developerfusion.com/article/84397/table-variables-v-temporary-tables-in-sql-server/, which has a lot more detail.
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