[wp-trac] [WordPress Trac] #15499: Add an index for get_lastpostmodified query

[WordPress Trac]

#15499: Add an index for get_lastpostmodified query
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 Reporter:  simonwheatley           |       Owner:  SergeyBiryukov
     Type:  enhancement             |      Status:  reviewing
 Priority:  normal                  |   Milestone:  6.2
Component:  Database                |     Version:  3.0.1
 Severity:  normal                  |  Resolution:
 Keywords:  has-patch dev-feedback  |     Focuses:  performance
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Comment (by OllieJones):

 Yes, a `$wp_db_version` bump is needed when adding an index to schema.php.

 Conversations about this in @core-performance have tended in the direction
 of avoiding core changes to indexes specifically for large sites, but
 rather putting such changes in a a "canonical plugin". (The meaning of
 "canonical plugin" is not yet defined as of this writing.)

 Suggestion: add this to @rjasdfiii and my [reindexing
 plugin](https://wordpress.org/plugins/index-wp-mysql-for-speed/) rather
 than core.

 At any rate, I'll take responsibility for this if you like.


 Workaround -- use wp-cli to add the index like this:


 {{{
 wp db query "ALTER TABLE wp_posts ADD KEY type_status_post_date_gmt
 (post_status, post_type, post_modified_gmt, post_date_gmt)
 }}}

 (Maybe it's time to develop an EXPLAIN addon to Query Monitor to show
 query plans.)

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Ticket URL: <https://core.trac.wordpress.org/ticket/15499#comment:55>
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