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What is a “Bitmap heap scan” in a query plan?
... is different from an index scan, where the index is visited row by row in order -- meaning a disk page may get visited multiple times.
Re: the question in your comment... Yep, that's exactly it.
An index scan will go through rows one by one, opening disk pages again and again, as many times as ...
How do you generate dynamic (parameterized) unit tests in python?
...,
["bar", "a", "b"],
["lee", "b", "b"],
])
def test_sequence(self, name, a, b):
self.assertEqual(a,b)
Which will generate the tests:
test_sequence_0_foo (__main__.TestSequence) ... ok
test_sequence_1_bar (__main__.TestSequence) ... FAIL
test_sequence_2_lee (__main_...
print call stack in C or C++
...ing stack frame). To translate these to something of use, there's backtrace_symbols(3).
Pay attention to the notes section in backtrace(3):
The symbol names may be unavailable
without the use of special linker
options.
For systems using the GNU linker, it is necessary to use the
...
Get name of current class?
...
obj.__class__.__name__ will get you any objects name, so you can do this:
class Clazz():
def getName(self):
return self.__class__.__name__
Usage:
>>> c = Clazz()
>>> c.getName()
'Clazz'
...
How to create module-wide variables in Python? [duplicate]
...st obvious way as appears below, the Python interpreter said the variable __DBNAME__ did not exist.
5 Answers
...
Is arr.__len__() the preferred way to get the length of an array in Python?
...
my_list = [1,2,3,4,5]
len(my_list)
# 5
The same works for tuples:
my_tuple = (1,2,3,4,5)
len(my_tuple)
# 5
And strings, which are really just arrays of characters:
my_string = 'hello world'
len(my_string)
# 11
It was in...
What does extern inline do?
... I'd like to add that for Microsoft's Visual C++, there's a __forceinline keyword that will enforce your function getting inlined. This is obviously a compiler-specific extension only for VC++.
– untitled8468927
Jan 17 '14 at 12:12
...
Redirecting to URL in Flask
...eturn a redirect:
import os
from flask import Flask,redirect
app = Flask(__name__)
@app.route('/')
def hello():
return redirect("http://www.example.com", code=302)
if __name__ == '__main__':
# Bind to PORT if defined, otherwise default to 5000.
port = int(os.environ.get('PORT', 5000)...
What is the difference between single and double quotes in SQL?
...r to that alias.
For example
(select account_id,count(*) "count of" from orders group by 1)sub
Here is a subquery from an orders table having account_id as Foreign key that I am aggregating to know how many orders each account placed. Here I have given one column any random name as "count of" f...
#define macro for debug printing in C?
...
If you use a C99 or later compiler
#define debug_print(fmt, ...) \
do { if (DEBUG) fprintf(stderr, fmt, __VA_ARGS__); } while (0)
It assumes you are using C99 (the variable argument list notation is not supported in earlier versions). The do { ... } while (0...