However,
phpMyAdmin developers have noticed??”and this was confirmed by other
developers at the 2007 MySQL Users Conference??”that some SELECT operations
involving a WHERE clause on information_schema are really slow (many minutes of
wait time) when the server hosts hundreds of databases or tables. Therefore, in the
current state of MySQL, caution must be exercised about using this feature in our
programming projects.
The $cfg['Servers'][$i]['hide_db'] parameter can be used to hide this
"database" to users that might be confused by the sudden apparition of a database
they know nothing about. It probably depends on their level of expertise in MySQL;
on a multi-user installation of phpMyAdmin, we cannot please everyone about this
parameter's value.
Profiling
We have previously seen the Profiling checkbox appear in query results:
Chapter 18
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When this box is checked, phpMyAdmin goes in a mode where every query
(including the current one) is being analyzed and a report about each MySQL
internal operation's execution time is displayed.
Although the profiling system can report additional information about operations
(like the CPU time and even the internal server's function names involved),
phpMyAdmin currently displays only the name of the operation and its duration.
At time of press, MySQL version 5.1.
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