[wp-trac] [WordPress Trac] #34870: dbDelta Not Specifying Key Length Duplicate Indexes

[WordPress Trac]

#34870: dbDelta Not Specifying Key Length Duplicate Indexes
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 Reporter:  charlestonsw  |       Owner:  pento
     Type:  defect (bug)  |      Status:  closed
 Priority:  normal        |   Milestone:  4.8
Component:  Database      |     Version:  2.8.1
 Severity:  normal        |  Resolution:  fixed
 Keywords:  has-patch     |     Focuses:  performance
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Comment (by johnjamesjacoby):

 > dropping/creating is a slow process which we don't want to trigger
 automatically.

 This sounds ripe for optimization.

 On installations like WordPress.com and WordPress.org, automatically re-
 indexing will result in database lock lasting minutes to hours (been
 there, done that, sorry Barry.) But for the majority of WordPress
 installations (if the 80/20 rule approximately applies) this process
 likely will not be very slow at all.

 We could try to calculate the number of affected rows aside of `dbDelta()`
 and set a reasonable default threshold where these kinds of alter's are
 allowed to run automatically.

 Something like:

 {{{
 define( 'DB_MAX_ALTERED_ROWS', 25000 );
 }}}

 If a database has more rows than the maximum number that can be alter'ed,
 then throw a database error?

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Ticket URL: <https://core.trac.wordpress.org/ticket/34870#comment:22>
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