From b4e5e47a0fd75bd5f70e16d40eb696453b962f73 Mon Sep 17 00:00:00 2001
From: Farhan Karmali <farhan6318@gmail.com>
Date: Wed, 21 Sep 2022 14:08:56 +0530
Subject: [PATCH] MDL-75667 admin: Avoid DB calls within loops on
 admin/blocks.php

---
 admin/blocks.php   | 17 +++++++++++------
 lib/db/install.xml |  3 ++-
 lib/db/upgrade.php | 13 +++++++++++++
 version.php        |  2 +-
 4 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/admin/blocks.php b/admin/blocks.php
index 19f5829a704..536a9e930f4 100644
--- a/admin/blocks.php
+++ b/admin/blocks.php
@@ -74,9 +74,15 @@
 
 /// Get and sort the existing blocks
 
-    if (!$blocks = $DB->get_records('block', array(), 'name ASC')) {
-        throw new \moodle_exception('noblocks', 'error');  // Should never happen.
-    }
+$sql = "SELECT b.* , COUNT(DISTINCT binst.id) as totalcount, COUNT(DISTINCT bcinst.id) as courseviewcount
+          FROM {block} b
+     LEFT JOIN {block_instances} binst ON binst.blockname = b.name
+     LEFT JOIN {block_instances} bcinst ON bcinst.blockname = b.name AND bcinst.pagetypepattern = 'course-view-*'
+      GROUP BY b.id, binst.blockname, bcinst.blockname
+      ORDER BY b.name ASC";
+if (!$blocks = $DB->get_records_sql($sql)) {
+    throw new \moodle_exception('noblocks', 'error');  // Should never happen.
+}
 
     $incompatible = array();
 
@@ -154,9 +160,8 @@
         // MDL-11167, blocks can be placed on mymoodle, or the blogs page
         // and it should not show up on course search page
 
-        $totalcount = $DB->count_records('block_instances', array('blockname'=>$blockname));
-        $count = $DB->count_records('block_instances', array('blockname'=>$blockname, 'pagetypepattern'=>'course-view-*'));
-
+        $totalcount = $blocks[$blockid]->totalcount;
+        $count = $blocks[$blockid]->courseviewcount;
         if ($count>0) {
             $blocklist = "<a href=\"{$CFG->wwwroot}/course/search.php?blocklist=$blockid&amp;sesskey=".sesskey()."\" ";
             $blocklist .= "title=\"$strshowblockcourse\" >$totalcount</a>";
diff --git a/lib/db/install.xml b/lib/db/install.xml
index 518e510b245..baa18195b80 100644
--- a/lib/db/install.xml
+++ b/lib/db/install.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<XMLDB PATH="lib/db" VERSION="20221017" COMMENT="XMLDB file for core Moodle tables"
+<XMLDB PATH="lib/db" VERSION="20221216" COMMENT="XMLDB file for core Moodle tables"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:noNamespaceSchemaLocation="../../lib/xmldb/xmldb.xsd"
 >
@@ -2747,6 +2747,7 @@
       <INDEXES>
         <INDEX NAME="parentcontextid-showinsubcontexts-pagetypepattern-subpagepattern" UNIQUE="false" FIELDS="parentcontextid, showinsubcontexts, pagetypepattern, subpagepattern"/>
         <INDEX NAME="timemodified" UNIQUE="false" FIELDS="timemodified"/>
+        <INDEX NAME="blocknameindex" UNIQUE="false" FIELDS="blockname"/>
       </INDEXES>
     </TABLE>
     <TABLE NAME="block_positions" COMMENT="Stores the position of a sticky block_instance on a another page than the one where it was added.">
diff --git a/lib/db/upgrade.php b/lib/db/upgrade.php
index 8a6f5ac745a..7de36e44385 100644
--- a/lib/db/upgrade.php
+++ b/lib/db/upgrade.php
@@ -3051,5 +3051,18 @@ privatefiles,moodle|/user/files.php';
         upgrade_main_savepoint(true, 2022120900.01);
     }
 
+    if ($oldversion < 2022121600.01) {
+        // Define index blocknameindex (not unique) to be added to block_instances.
+        $table = new xmldb_table('block_instances');
+        $index = new xmldb_index('blocknameindex', XMLDB_INDEX_NOTUNIQUE, ['blockname']);
+
+        // Conditionally launch add index blocknameindex.
+        if (!$dbman->index_exists($table, $index)) {
+            $dbman->add_index($table, $index);
+        }
+        // Main savepoint reached.
+        upgrade_main_savepoint(true, 2022121600.01);
+    }
+
     return true;
 }
diff --git a/version.php b/version.php
index 377236398a3..cd7501ef38f 100644
--- a/version.php
+++ b/version.php
@@ -29,7 +29,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$version  = 2022121600.00;              // YYYYMMDD      = weekly release date of this DEV branch.
+$version  = 2022121600.01;              // YYYYMMDD      = weekly release date of this DEV branch.
                                         //         RR    = release increments - 00 in DEV branches.
                                         //           .XX = incremental changes.
 $release  = '4.2dev (Build: 20221216)'; // Human-friendly version name