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When and why are database joins expensive?
...s back to mitigating the size of the working set. Joins involving properly selected keys with correctly set up indexes are cheap, not expensive, because they allow significant pruning of the result before the rows are materialised.
Materialising the result involves bulk disk reads which are the mo...
Why use armeabi-v7a code over armeabi code?
...project I make use of multiple .so files. These are located at the armeabi and armeabi-v7a folder. Unfortunately one of the .so files is a 6MB and I need to reduce file size. Instead of having a fat APK file, I would like to use just the armeabi files and remove the armeabi-v7a folder.
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How to import Google Web Font in CSS file?
...e (+) icon next to it. In bottom-left corner, a container titled "1 Family Selected" will appear. Click it, and it will expand. Use the "Customize" tab to select options, and then switch back to "Embed" and click "@import" under "Embed Font". Copy the CSS between the <style> tags into your sty...
How do I see the current encoding of a file in Sublime Text?
...or re-open the file in a different encoding.
– Immo Landwerth
Dec 22 '13 at 23:45
4
I don't have ...
What is an SSTable?
In BigTable/GFS and Cassandra terminology, what is the definition of a SSTable?
4 Answers
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Insert auto increment primary key to existing table
...etrieve it by id immediately, MySQL offers LAST_INSERT_ID() for that value SELECT * FROM table_name WHERE id = LAST_INSERT_ID() and most programming language APIs offer some function/method to return that value in the application code.
– Michael Berkowski
Jan 2...
If table exists drop table then create it, if it does not exist just create it
...up the old table,
obviously.
Wrapping all statements with something like SELECT GET_LOCK('__upgrade', -1); ... DO RELEASE_LOCK('__upgrade'); allows to just invoke all statements sequentially without error checking, but I don't think it's a good idea: complexity increases and locking functions in M...
SQL-Server: Error - Exclusive access could not be obtained because the database is in use
...WITH REPLACE) in optoins tab at left hand side.
Uncheck all other options.
Select source and destination database.
Click ok.
That's it.
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How to detect if my shell script is running through a pipe?
How do I detect from within a shell script if its standard output is being sent to a terminal or if it's piped to another process?
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Can existing virtualenv be upgraded gracefully?
I have a virtualenv created for Python 2.5 and want to "upgrade" it to Python 2.6.
5 Answers
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