added an index on the groupings table for the userId column

docs/changelog/7.x.x.txt

@@ -13,6 +13,8 @@
    LIMIT clauses.
  - add: SyndicatedContent wobject now has more ways of representing the long
    description from the RSS feed.
+ - Added an index on the userId column of the groupings table to speed up
+   queries for groupIds by userId (instead of the usual userIds by groupId)
 
 
 

docs/upgrades/upgrade_7.3.19-7.4.0.pl

@@ -21,6 +21,7 @@ my $quiet; # this line required
 my $session = start(); # this line required
 
 # upgrade functions go here
+addGroupingsIndexOnUserId($session);
 fixProfileDataWithoutFields($session);
 buildNewUserProfileTable($session);
 addAttachmentsToEvents($session);
@@ -37,6 +38,32 @@ finish($session); # this line required
 
 #----------------------------------------------------------------------------
 
+sub addGroupingsIndexOnUserId {
+    my $session     = shift;
+    my $db          = $session->db;
+    print qq{\tAdding index on `userId` column in `groupings` table for performance... } unless $quiet;
+
+    # See if we even NEED to add this index, if we don't it just takes up
+    # disk/memory space.
+    my %createTable 
+        = $db->quickHash(
+            "SHOW CREATE TABLE `groupings`"
+        );
+
+    if ($createTable{'Create Table'} =~ /KEY\s+`[^`]+`\s+[(]`userId`[)]/) {
+        print   " Skipped!\n",
+                "\t\tAn index already exists on the `userId` column in the `groupings` table\n"
+                    unless $quiet;
+    }
+    else {
+        print   "\n\t\tThis may take a while... " unless $quiet;
+        $db->write("ALTER TABLE `groupings` ADD INDEX `userId` (`userId`)");
+        print   "DONE!\n" unless $quiet;
+    }
+}
+
+#----------------------------------------------------------------------------
+
 sub fixProfileDataWithoutFields {
     my $session     = shift;
     my $db          = $session->db;