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How does database indexing work? [closed]
...arising from the file systems size limits, careful thought must be used to select the correct fields to index.
Since indices are only used to speed up the searching for a matching field within the records, it stands to reason that indexing fields used only for output would be simply a waste of disk...
How to kill/stop a long SQL query immediately?
...uted and is suspended, and found that there are many instances of the same SELECT SQL having the same SPID. When I try to execute the command KILL 114 - here 114 is the SPID value of my suspended query. I get the error shon below: Please guide. Msg 102, Level 15, State 1, Line 2 Incorrect syntax...
nginx server_name wildcard or catch-all
...ich serves several websites. The first is a status message on the server's IP address. The second is an admin console on admin.domain.com . These work great. Now I'd like all other domain requests to go to a single index.php - I have loads of domains and subdomains and it's impractical to list th...
Difference between @import and link in CSS
...
The <link> directive can allow for multiple css be loaded and interpreted asyncronously.
the @import directive forces the browser* to wait until the imported script is loaded inline to the parent script before it can be correctly processed by it's engine, since t...
How can I delete the current line in Emacs?
...lest way to delete (kill) a full line, from any point
on the line, without selecting anything, is:
C-w ; kill-region
It is versatile in deleting whatever is selected, or a line by default
if nothing is selected.
Given the question, you're probably also interested in replicating
Vim's "yank", yy...
TCP loopback connection vs Unix Domain Socket performance
... the overhead of TCP (congestion control, flow control, stream management (IP packet ordering, retransmission, etc) ). Unix domain sockets do not do any of the above because it was designed from the ground up to be ran locally, meaning no congestion issues, no speed differences between server/client...
Command line for looking at specific port
...080"
In bash:
netstat -na | grep "8080"
In PowerShell:
netstat -na | Select-String "8080"
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How to move the cursor word by word in the OS X Terminal
...e sequences for you:
Open Terminal preferences (cmd+,);
At Settings tab, select Keyboard and double-click ⌥ ← if it's there, or add it if it's not.
Set the modifier as desired, and type the shortcut key in the box: esc+B, generating the text \033b (you can't type this text manually).
Repeat fo...
SQL Server indexes - ascending or descending, what difference does it make?
...TE INDEX ix_index ON mytable (col1, col2 DESC);
can be used for either:
SELECT *
FROM mytable
ORDER BY
col1, col2 DESC
or:
SELECT *
FROM mytable
ORDER BY
col1 DESC, col2
, but not for:
SELECT *
FROM mytable
ORDER BY
col1, col2
An index on a single colum...
How to convert std::string to lower case?
...y unrelated) definition of tolower which would end up being preferentially selected without the ::.
– Charles Ofria
Jul 30 '16 at 16:43
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