[dw-free] negative "load tags" result is not cached, results in large amount of queries

[fu]

[commit: http://hg.dwscoalition.org/dw-free/rev/454004989469]

http://bugs.dwscoalition.org/show_bug.cgi?id=3661

Cache results when journal has no tags.

Patch by exor674.

Files modified:

• cgi-bin/LJ/Tags.pm

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diff -r bafea8052e02 -r 454004989469 cgi-bin/LJ/Tags.pm
--- a/cgi-bin/LJ/Tags.pm	Thu May 12 18:02:17 2011 +0800
+++ b/cgi-bin/LJ/Tags.pm	Thu May 12 18:11:15 2011 +0800
@@ -171,19 +171,18 @@
         my $dbcr = ($dbcrs{$cid} ||= LJ::get_cluster_def_reader($cid))
             or next;
 
+        my @all_jids = map { $_ + 0 } keys %{$need{$cid}};
+
         # get the tags from the database
-        my $in = join(',', map { $_ + 0 } keys %{$need{$cid}});
+        my $in = join(',', @all_jids);
         my $tagrows = $dbcr->selectall_arrayref("SELECT journalid, kwid, parentkwid, display FROM usertags WHERE journalid IN ($in)");
-        next if $dbcr->err || ! $tagrows;
+        next if $dbcr->err;
 
         # break down into data structures
         my %tags; # ( jid => { kwid => display } )
         $tags{$_->[0]}->{$_->[1]} = $_->[3]
             foreach @$tagrows;
 
-        # if they have no tags...
-        next unless %tags;
-
         # now turn this into a tentative results hash: { userid => { tagid => { name => tagname, ... }, ... } }
         # this is done by combining the information we got from the tags lookup along with
         # the stuff from the keyword lookup.  we need the relevant rows from both sources
@@ -209,11 +208,14 @@
         # get security counts
         my @resjids = keys %$res;
         my $ids = join(',', map { $_+0 } @resjids);
-        next unless $ids;
+
+        my $counts = [];
 
         # populate security counts
-        my $counts = $dbcr->selectall_arrayref("SELECT journalid, kwid, security, entryct FROM logkwsum WHERE journalid IN ($ids)");
-        next if $dbcr->err || ! $counts;
+        if ( @resjids ) {
+            $counts = $dbcr->selectall_arrayref("SELECT journalid, kwid, security, entryct FROM logkwsum WHERE journalid IN ($ids)");
+            next if $dbcr->err;
+        }
 
         # setup some helper values
         my $public_mask = 1 << 63;
@@ -253,7 +255,8 @@
         }
 
         # default securities to private and store to memcache
-        foreach my $jid (@resjids) {
+        foreach my $jid (@all_jids) {
+            $res->{$jid} ||= {};
             $res->{$jid}->{$_}->{security_level} ||= 'private'
                 foreach keys %{$res->{$jid}};
 
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