From: Aryeh Gregor <simetrical@users.mediawiki.org>
Date: Thu, 10 Jul 2008 18:05:52 +0000 (+0000)
Subject: Add overly wordy comment explaining why logs can't be filtered by prefix in $wgMiserM... 
X-Git-Tag: 1.31.0-rc.0~46565
X-Git-Url: http://git.cyclocoop.org/data/Fool?a=commitdiff_plain;h=779b716bac729b4ca38abe29f00f8768f02731f5;p=lhc%2Fweb%2Fwiklou.git

Add overly wordy comment explaining why logs can't be filtered by prefix in $wgMiserMode, since I keep on forgetting.
---

diff --git a/includes/LogEventsList.php b/includes/LogEventsList.php
index d9635418c6..d49f636b4c 100644
--- a/includes/LogEventsList.php
+++ b/includes/LogEventsList.php
@@ -504,6 +504,17 @@ class LogPager extends ReverseChronologicalPager {
 
 		$this->title = $title->getPrefixedText();
 		$ns = $title->getNamespace();
+		# Using the (log_namespace, log_title, log_timestamp) index with a
+		# range scan (LIKE) on the first two parts, instead of simple equality,
+		# makes it unusable for sorting.  Sorted retrieval using another index
+		# would be possible, but then we might have to scan arbitrarily many
+		# nodes of that index. Therefore, we need to avoid this if $wgMiserMode
+		# is on.
+		#
+		# This is not a problem with simple title matches, because then we can
+		# use the page_time index.  That should have no more than a few hundred
+		# log entries for even the busiest pages, so it can be safely scanned
+		# in full to satisfy an impossible condition on user or similar.
 		if( $pattern && !$wgMiserMode ) {
 			# use escapeLike to avoid expensive search patterns like 't%st%'
 			$safetitle = $this->mDb->escapeLike( $title->getDBkey() );