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postgresql COUNT(DISTINCT …) very slow
... amount of work_mem (where hashing will produce relatevely large amount of batches). Since that, it's not always bad to use COUNT (DISTINCT()_, isn't?
– St.Antario
Oct 12 '15 at 10:39
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sql server #region
...ain Transact-SQL statements should not be grouped together within the same batch (statement block). Could anyone tell me why they should not be grouped?
– Jacob Phan
May 4 '16 at 4:26
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What's the difference between libev and libevent?
...e designed for async i/o scheduling, and both engages epoll on linux, and kqueue on FreeBSD, etc.
2 Answers
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Get a list of URLs from a site [closed]
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But there is a limit of 5000 links!..:( I'm looking for any free php sitemap generator script.
– Jenson M John
Aug 3 '13 at 10:25
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How to restart Jenkins manually?
...Restart - Allows all running jobs to complete. New jobs will remain in the queue to run after the restart is complete.
(jenkins_url)/restart - Forces a restart without waiting for builds to complete.
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How to check if activity is in foreground or in visible background?
...xtends TimerTask
{
private static final long FOREGROUND_CHECK_PERIOD = 5000;
private static final long FIRST_DELAY = 3000;
private Activity m_activity;
private Timer m_timer;
public ActivityForegroundChecker (Activity p_activity)
{
m_activity = p_acti...
How to force garbage collector to run?
...etter performance": it simply blocks until all objects in the finalisation queue have been finalised (objects which might have been put there by your previous call to Collect). If you want a chance for those objects to be collected then you need another call to Collect after calling WaitForPendingFi...
How to detect a Christmas Tree? [closed]
...ightthr=0.95, satthr=0.7,
valthr=0.7, monothr=220, maxpoints=5000, proxthresh=0.04):
# Convert rgb image to monochrome for
gryimg = np.asarray(Image.fromarray(rgbimg).convert('L'))
# Convert rgb image (uint, 0-255) to hsv (float, 0.0-1.0)
hsvimg = colors.rgb_to_hsv(rgb...
Print new output on same line [duplicate]
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This answer turned up in the low quality review queue, presumably because you don't provide any explanation of the code. If this code answers the question, consider adding adding some text explaining the code in your answer. This way, you are far more likely to get more up...
How do I get list of all tables in a database using TSQL?
...eplication filter stored procedure
S: System table
SN: Synonym
SQ: Service queue
TA: Assembly (CLR) DML trigger
TF: Table function
TR: SQL DML Trigger
TT: Table type
U: User table
UQ: UNIQUE constraint (type is K)
V: View
X: Extended stored procedure
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