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How to speed up insertion performance in PostgreSQL
...rypto module) is (a lot) faster than uuid_generate_v4()
=# explain analyze select uuid_generate_v4(),* from generate_series(1,10000);
QUERY PLAN
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“On-line” (iterator) algorithms for estimating statistical median, mode, skewness, kurtosis?
...oints you have, in theory you only have to partially sort, e.g. by using a selection algorithm. However, that doesn't help too much with billions of values. I would suggest using frequency counts, see the next section.
Median and Mode with Frequency Counts
If it is integers, I would count
frequenc...
On localhost, how do I pick a free port number?
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Bind the socket to port 0. A random free port from 1024 to 65535 will be selected. You may retrieve the selected port with getsockname() right after bind().
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How to calculate time in hours between two dates in iOS
...developer.apple.com/library/mac/navigation/
or if you are using Xcode just select help/documentation from the menu.
See: how-to-convert-an-nstimeinterval-seconds-into-minutes
--edit: See ÐąrέÐέvil's answer below for correctly handling daylight savings/leap seconds
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Write bytes to file
...gth)
.Where(x => x % 2 == 0)
.Select(x => Convert.ToByte(hex.Substring(x, 2), 16))
.ToArray();
}
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How can I tell if my server is serving GZipped content?
...erested). You can tell using Developer Tools (F12). Go to the Network tab, select the file you want to examine and then look at the Headers tab on the right. If you are gzipped, then you will see that in the Content-Encoding.
In this example, slider.jpg is indeed being gzipped.
Compare that to t...
What is the difference between SqlCommand.CommandTimeout and SqlConnection.ConnectionTimeout?
...ndTimeout = timeout limit for your SQL query. Means, how much time a (eg: SELECT, UPDATE) query can take for its execution. If it exceeds SqlCommand.CommandTimeout, then it stops execution. A command timeout error will occur.
SqlConnection.ConnectionTimeout = timeout limit for your connection. Mea...
How to unset a JavaScript variable?
...all browsers. Running in real documents, your code examples are correct. I selected your answer as correct, but I'd appreciate it if you can edit it to include explaining window.a = 1; delete window.a; and possibly the mechanism. I can do so as well if you don't mind.
– Guss
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Separate Back Stack for each tab in Android using Fragments
...t(tabId).size() == 0){
/*
* First time this tab is selected. So add first fragment of that tab.
* Dont need animation, so that argument is false.
* We are adding a new fragment which is not present in stack. So add to stack is true.
*/
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How do I specify “close existing connections” in sql script
...RE @isStatAsyncOn bit
DECLARE @jobId int
DECLARE @sqlString nvarchar(500)
SELECT @dbId = database_id,
@isStatAsyncOn = is_auto_update_stats_async_on
FROM sys.databases
WHERE name = 'db_name'
IF @isStatAsyncOn = 1
BEGIN
ALTER DATABASE [db_name] SET AUTO_UPDATE_STATISTICS_ASYNC OFF
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