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Why does PostgreSQL perform sequential scan on indexed column?
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If the SELECT returns more than approximately 5-10% of all rows in the table, a sequential scan is much faster 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...
How do I update zsh to the latest version?
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answered Jul 15 '13 at 8:30
Mike LiMike Li
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How do I test for an empty string in a Bash case statement?
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answered Jul 10 '13 at 16:10
ricirici
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How to copy in bash all directory and files recursive?
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edited Jun 27 '17 at 1:08
zviad
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answered Jun 18 '14 at 5:45
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How can I get nth element from a list?
...re, the operator used is !!.
I.e. [1,2,3]!!1 gives you 2, since lists are 0-indexed.
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What is the difference between “def” and “val” to define a function
... time (new instance of Function1).
def even: Int => Boolean = _ % 2 == 0
even eq even
//Boolean = false
val even: Int => Boolean = _ % 2 == 0
even eq even
//Boolean = true
With def you can get new function on every call:
val test: () => Int = {
val r = util.Random.nextInt
() => ...
How to redirect output with subprocess in Python?
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UPDATE: os.system is discouraged, albeit still available in Python 3.
Use os.system:
os.syst...
Ansible: Set variable to file content
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Note that lookup runs locally, while the cat command in @TesterJeff's example is running on the remote machine.
– Alex...
Should the .gradle folder be added to version control?
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ShornShorn
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How to remove debugging from an Express app?
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Adaptabi
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answered Jul 24 '11 at 15:44
AlfredAlfred
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