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How do I find which transaction is causing a “Waiting for table metadata lock” state?
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SHOW ENGINE INNODB STATUS \G
Look for the Section -
TRANSACTIONS
We can use INFORMATION_SCHEMA Tables.
Useful Queries
To check about all the locks transactions are waiting for:
USE INFORMATION_SCHEMA;
SELECT * FROM INNODB_LOCK_WAITS;
A list of blocking transactions:
SELECT *
FROM INNO...
What is The difference between ListBox and ListView
What is the difference between WPF's ListBox and ListView? I can not find any significant difference in their properties. Is there different typical use?
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Iterating Over Dictionary Key Values Corresponding to List in Python
...gue.keys():
runs_scored, runs_allowed = map(float, league[team])
You can also iterate over both the keys and the values at once by iterating over league.items():
for team, runs in league.items():
runs_scored, runs_allowed = map(float, runs)
You can even perform your tuple unpacking whil...
Debugging iframes with Chrome developer tools
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In the Developer Tools in Chrome, there is a bar along the top, called the Execution Context Selector (h/t felipe-sabino), just under the Elements, Network, Sources... tabs, that changes depending on the context of the current tab. When in the Console tab there is a dropdown in that bar ...
displayname attribute vs display attribute
...ey both give you the same results but the key difference I see is that you cannot specify a ResourceType in DisplayName attribute. For an example in MVC 2, you had to subclass the DisplayName attribute to provide resource via localization. Display attribute (new in MVC3 and .NET4) supports ResourceT...
LINQ to Entities does not recognize the method
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As you've figured out, Entity Framework can't actually run your C# code as part of its query. It has to be able to convert the query to an actual SQL statement. In order for that to work, you will have to restructure your query expression into an expression that En...
What does “@” mean in Windows batch scripts
... while the latter prints
H:\Stuff>echo foo
foo
(here, at least). As can be seen the command that is run is visible, too.
echo off will turn this off for the complete batch file. However, the echo off call itself would still be visible. Which is why you see @echo off in the beginning of batch...
How to get the root dir of the Symfony2 application?
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UPDATE 2018-10-21:
As of this week, getRootDir() was deprecated. Please use getProjectDir() instead, as suggested in the comment section by Muzaraf Ali.
—-
Use this:
$this->get('kernel')->getRootDir();
And if you want the web root:
$this->get('kernel')->getRootD...
Execute SQLite script
...ntation! I know we often reach for Google before the docs, but in SQLite's case, the docs really are technical writing at its best. It's clean, clear, and concise.
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Find the max of two or more columns with pandas
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You can get the maximum like this:
>>> import pandas as pd
>>> df = pd.DataFrame({"A": [1,2,3], "B": [-2, 8, 1]})
>>> df
A B
0 1 -2
1 2 8
2 3 1
>>> df[["A", "B"]]
A B
0 1 -2
1 2...