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What is JavaScript garbage collection?
...o reference point to it
Mark-and-sweep algorithm: connect each objects to root source. any object doesn't connect to root or other object. this object will be removed.
currently most modern browsers using the second algorithm.
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Fastest way to count exact number of rows in a very large table?
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The fastest way by far on MySQL is:
SHOW TABLE STATUS;
You will instantly get all your tables with the row count (which is the total) along with plenty of extra information if you want.
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Primary key or Unique index?
...hen it tries to insert the value 1 into this column for a second time.
In MySQL a unique constraint allows multiple NULLs.
It is possible to make a unique index on mutiple columns.
Primary key versus unique index
Things that are the same:
A primary key implies a unique index.
Things that are...
What is the “realm” in basic authentication
...nge. The realm value
(case-sensitive), in combination with the canonical root URL of the
server being accessed, defines the protection space. These realms
allow the protected resources on a server to be partitioned into a set
of protection spaces, each with its own authentication scheme and/...
How to generate UML diagrams (especially sequence diagrams) from Java code?
... named MyProject.uml
Move generated MyProject.uml which was generated at root, to UML folder, Eclipse will ask you If you wanted to replace it click yes. What we did in here was that we replaced an empty model with a generated one.
ALT+W -> show view -> papyrus -> model explorer
In that v...
What is the fastest way to compute sin and cos together?
...nd be aware that using this method involves computing a power and a square root, so if performance is important, make sure to verify that this is actually faster than computing the other trig function directly.
– Tyler McHenry
Apr 21 '10 at 14:11
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How to push new branch without history
...rst commit made on this new branch will have no parents and it will be the root of a new history totally disconnected from all the other branches and commits.
The index and the working tree are adjusted as if you had previously run "git checkout <start_point>". This allows you to start a new h...
How to write DataFrame to postgres table?
There is DataFrame.to_sql method, but it works only for mysql, sqlite and oracle databases. I cant pass to this method postgres connection or sqlalchemy engine.
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How to log cron jobs?
... send emails. Most systems will send unhandled cron job output by email to root or the corresponding user.
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What is your preferred php deployment strategy? [closed]
...dotCloud, in addition to PHP (see their PHP quickstart) it can also deploy MySQL, MongoDB and a whole bunch of additional services. It also has nice goodies like zero-downtime deployment, instant rollback, full support for SSL and websocket, etc. And there's a free tier which is always nice :)
Of c...