From 3c028a80d421d65c4080f7a1d362795ed2fb3b99 Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@gmail.com>
Date: Wed, 23 Sep 2015 18:16:26 +0000
Subject: [PATCH] Allow `comment_exists()` to match based on GMT date.

The `comment_date_gmt` field of the `wp_comments` table is indexed, which makes
`WHERE` matches against the field much faster than against the unindexed
`comment_date`. For bulk operations like data import, the speed difference can
be meaningful.

We continue to default to 'blog' for `$timezone`, to preserve compatibility
with existing uses.

Props apokalyptik.
Fixes #33871.
Built from https://develop.svn.wordpress.org/trunk@34460


git-svn-id: http://core.svn.wordpress.org/trunk@34424 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-admin/includes/comment.php | 19 +++++++++++++++----
 wp-includes/version.php       |  2 +-
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/wp-admin/includes/comment.php b/wp-admin/includes/comment.php
index dfb39220ab..32cb56b5fb 100644
--- a/wp-admin/includes/comment.php
+++ b/wp-admin/includes/comment.php
@@ -9,19 +9,30 @@
 /**
  * Determine if a comment exists based on author and date.
  *
+ * For best performance, use `$timezone = 'gmt'`, which queries a field that is properly indexed. The default value
+ * for `$timezone` is 'blog' for legacy reasons.
+ *
  * @since 2.0.0
+ * @since 4.4.0 Added the `$timezone` parameter.
  *
  * @global wpdb $wpdb WordPress database abstraction object.
  *
- * @param string $comment_author Author of the comment
- * @param string $comment_date Date of the comment
+ * @param string $comment_author Author of the comment.
+ * @param string $comment_date   Date of the comment.
+ * @param string $timezone       Timezone. Accepts 'blog' or 'gmt'. Default 'blog'.
+ *
  * @return mixed Comment post ID on success.
  */
-function comment_exists($comment_author, $comment_date) {
+function comment_exists( $comment_author, $comment_date, $timezone = 'blog' ) {
 	global $wpdb;
 
+	$date_field = 'comment_date';
+	if ( 'gmt' === $timezone ) {
+		$date_field = 'comment_date_gmt';
+	}
+
 	return $wpdb->get_var( $wpdb->prepare("SELECT comment_post_ID FROM $wpdb->comments
-			WHERE comment_author = %s AND comment_date = %s",
+			WHERE comment_author = %s AND $date_field = %s",
 			stripslashes( $comment_author ),
 			stripslashes( $comment_date )
 	) );
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 1387e19a9a..24af754281 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.4-alpha-34459';
+$wp_version = '4.4-alpha-34460';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.