[wp-trac] [WordPress Trac] #20213: Pagination fails silently when mysql.trace_mode is on

[WordPress Trac]

#20213: Pagination fails silently when mysql.trace_mode is on
------------------------------+-----------------------------
 Reporter:  ManuelRazzari     |      Owner:
     Type:  enhancement       |     Status:  new
 Priority:  normal            |  Milestone:  Awaiting Review
Component:  Warnings/Notices  |    Version:  3.4
 Severity:  normal            |   Keywords:
------------------------------+-----------------------------
 A sysadmin left enabled '''mysql.trace_mode''' on php.ini without me
 knowing about it, and I spent hours trying to find out why the
 '''next_posts_link''' wasn't showing up.

 This is very hard to debug, because
 * it fails silently, with no error to look for
 * it's hard to repro on a dev server, which may not have the same php.ini
 settings as in staging/prod (ideally should, but rare for 99% of devs)

 Other people had this same issue:
 * "[http://wordpress.org/support/topic/page-navi-not-working-with-
 mysql-5134-amp-php-529 No error, it's just not working]"
 * "[http://wordpress.org/support/topic/archives-not-showing-nextprev-
 windows-only-crazy Am I going crazy]"?
 * Trace_mode defaulted to "on" in
 [http://stackoverflow.com/a/869957/128329 this guy's] install (!).

 I've read through #18536, #10469 and related issues, hoping that usage of
 SQL_CALC_FOUND_ROWS would be removed, but it seems to be still there, in
 trunk.

 So I guess a "fix" for this would be to check for trace_mode and, if
 enabled, notify admin users on the wp-admin dashboard.

 Meanwhile, I've added a note about this on the
 [http://codex.wordpress.org/Function_Reference/next_posts_link
 next_posts_link] page.

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Ticket URL: <http://core.trac.wordpress.org/ticket/20213>
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