[aur-dev] [PATCH] Cache all front page stats in APC if available

[Dan McGee]

Use the APC cache to store all of the counts and the recently updated
package list in a cache, which cuts down on the number of database queries
needed. If the data isn't perfectly up to date we will survive.

This version of the patch will also cache the relevant counts for individual
logged-in users and is more careful about checking whether the value
actually exists in the cache by using the status reference to apc_fetch().

Signed-off-by: Dan McGee <dan at archlinux.org>
---

Sorry I keep tweaking this patch, but I've extensively tested this version
locally with APC both on and off and it seems to work quite well.

We even cache some user-specific stuff now for what its worth. Since our cache
expires relatively quickly, this isn't going to be a used a lot but when it is
it will save some database load.

-Dan

 web/lib/stats.inc                    |   53 +++++++++++++++++++++++-----------
 web/template/stats/updates_table.php |    5 +--
 2 files changed, 38 insertions(+), 20 deletions(-)

diff --git a/web/lib/stats.inc b/web/lib/stats.inc
index 6fbc033..e2b7f90 100644
--- a/web/lib/stats.inc
+++ b/web/lib/stats.inc
@@ -2,10 +2,39 @@
 
 include_once('aur.inc');
 
+# Check if APC extension is loaded
+if (!defined('EXTENSION_LOADED_APC'))
+	define('EXTENSION_LOADED_APC', extension_loaded('apc'));
+$apc_prefix = 'aur:';
+
+# run a simple db query, retrieving and/or caching the value if APC
+# is available for use
+#
+function db_cache_value($dbq, $dbh, $key)
+{
+	if(!(EXTENSION_LOADED_APC && ($ret = apc_fetch($key)))) {
+		$result = db_query($dbq, $dbh);
+		$row = mysql_fetch_row($result);
+		$ret = $row[0];
+		# set the TTL here in seconds: 300 seconds = 5 minutes
+		apc_store($key, $ret, 300);
+	}
+	return $ret;
+}
+
 function updates_table($dbh)
 {
-	$q = 'SELECT * FROM Packages WHERE DummyPkg != 1 ORDER BY GREATEST(SubmittedTS,ModifiedTS) DESC LIMIT 0 , 10';
-	$newest_packages = db_query($q, $dbh);
+	$key = $apc_prefix . 'recent_updates';
+	if(!(EXTENSION_LOADED_APC && ($newest_packages = apc_fetch($key)))) {
+		$q = 'SELECT * FROM Packages WHERE DummyPkg != 1 ORDER BY GREATEST(SubmittedTS,ModifiedTS) DESC LIMIT 0 , 10';
+		$result = db_query($q, $dbh);
+
+		$newest_packages = new ArrayObject();
+		while ($row = mysql_fetch_assoc($result)) {
+			$newest_packages->append($row);
+		}
+		apc_store($key, $newest_packages, 300);
+	}
 	include('stats/updates_table.php');
 }
 
@@ -42,30 +71,20 @@ function general_stats_table($dbh)
 {
 	# AUR statistics
 	$q = "SELECT count(*) FROM Packages,PackageLocations WHERE Packages.LocationID = PackageLocations.ID AND PackageLocations.Location = 'unsupported'";
-	$result = db_query($q, $dbh);
-	$row = mysql_fetch_row($result);
-	$unsupported_count = $row[0];
+	$unsupported_count = db_cache_value($q, $dbh, $apc_prefix . 'unsupported_count');
 
 	$q = "SELECT count(*) FROM Packages,PackageLocations WHERE Packages.LocationID = PackageLocations.ID AND PackageLocations.Location = 'community'";
-	$result = db_query($q, $dbh);
-	$row = mysql_fetch_row($result);
-	$community_count = $row[0];
+	$community_count = db_cache_value($q, $dbh, $apc_prefix . 'community_count');
 
 	$q = "SELECT count(*) from Users";
-	$result = db_query($q, $dbh);
-	$row = mysql_fetch_row($result);
-	$user_count = $row[0];
+	$user_count = db_cache_value($q, $dbh, $apc_prefix . 'user_count');
 
 	$q = "SELECT count(*) from Users,AccountTypes WHERE Users.AccountTypeID = AccountTypes.ID AND AccountTypes.AccountType = 'Trusted User'";
-	$result = db_query($q, $dbh);
-	$row = mysql_fetch_row($result);
-	$tu_count = $row[0];
+	$tu_count = db_cache_value($q, $dbh, $apc_prefix . 'tu_count');
 
 	$targstamp = intval(strtotime("-7 days"));
 	$q = "SELECT count(*) from Packages WHERE (Packages.SubmittedTS >= $targstamp OR Packages.ModifiedTS >= $targstamp)";
-	$result = db_query($q, $dbh);
-	$row = mysql_fetch_row($result);
-	$update_count = $row[0];
+	$update_count = db_cache_value($q, $dbh, $apc_prefix . 'update_count');
 
 	include('stats/general_stats_table.php');
 }
diff --git a/web/template/stats/updates_table.php b/web/template/stats/updates_table.php
index e1eb888..9d1af01 100644
--- a/web/template/stats/updates_table.php
+++ b/web/template/stats/updates_table.php
@@ -6,8 +6,7 @@
 </th>
 </tr>
 
-<?php while ($row = mysql_fetch_assoc($newest_packages)): ?>
-
+<?php foreach ($newest_packages->getIterator() as $row): ?>
 <tr>
 <td class="boxSoft">
 <span class="f4"><span class="blue">
@@ -34,7 +33,7 @@ endif;
 </td>
 </tr>
 
-<?php endwhile; ?>
+<?php endforeach; ?>
 
 </table>
 
-- 
1.6.1