Fix for mysql subquery problem

diff --git a/Changes b/Changes
index 1869f7f..ab51a54 100644 (file)
--- a/Changes
+++ b/Changes
@@ -8,6 +8,9 @@ Revision history for DBIx::Class
           an exception
         - fixed corner case when populate() erroneously falls back to
           create()
+        - work around braindead mysql when doing subquery counts on
+          resultsets containing identically named columns from several
+          tables
 
 0.08103 2009-05-26 19:50:00 (UTC)
         - Multiple $resultset -> count/update/delete fixes. Now any

diff --git a/lib/DBIx/Class/ResultSet.pm b/lib/DBIx/Class/ResultSet.pm
index 079edc6..e105e79 100644 (file)
--- a/lib/DBIx/Class/ResultSet.pm
+++ b/lib/DBIx/Class/ResultSet.pm
@@ -1329,7 +1329,7 @@ sub _rs_update_delete {
 
     my $subrs = (ref $self)->new($rsrc, $attrs);
 
-    return $self->result_source->storage->subq_update_delete($subrs, $op, $values);
+    return $self->result_source->storage->_subq_update_delete($subrs, $op, $values);
   }
   else {
     return $rsrc->storage->$op(

diff --git a/lib/DBIx/Class/Storage/DBI.pm b/lib/DBIx/Class/Storage/DBI.pm
index 89b9096..e96dece 100644 (file)
--- a/lib/DBIx/Class/Storage/DBI.pm
+++ b/lib/DBIx/Class/Storage/DBI.pm
@@ -1104,7 +1104,7 @@ sub delete {
 # Genarating a single PK column subquery is trivial and supported
 # by all RDBMS. However if we have a multicolumn PK, things get ugly.
 # Look at _multipk_update_delete()
-sub subq_update_delete {
+sub _subq_update_delete {
   my $self = shift;
   my ($rs, $op, $values) = @_;
 
@@ -1269,7 +1269,7 @@ sub count_grouped {
   }
 
   $sub_attrs->{group_by} ||= [ map { "$attrs->{alias}.$_" } ($source->primary_columns) ];
-  $sub_attrs->{select} = $self->_grouped_count_select ($sub_attrs);
+  $sub_attrs->{select} = $self->_grouped_count_select ($source, $sub_attrs);
 
   $attrs->{from} = [{
     count_subq => $source->resultset_class->new ($source, $sub_attrs )->as_query
@@ -1288,8 +1288,8 @@ sub count_grouped {
 # choke in various ways.
 #
 sub _grouped_count_select {
-  my ($self, $attrs) = @_;
-  return $attrs->{group_by};
+  my ($self, $source, $rs_args) = @_;
+  return $rs_args->{group_by};
 }
 
 sub source_bind_attributes {

diff --git a/lib/DBIx/Class/Storage/DBI/mysql.pm b/lib/DBIx/Class/Storage/DBI/mysql.pm
index dcdeafe..77aadff 100644 (file)
--- a/lib/DBIx/Class/Storage/DBI/mysql.pm
+++ b/lib/DBIx/Class/Storage/DBI/mysql.pm
@@ -53,10 +53,23 @@ sub lag_behind_master {
 
 # MySql can not do subquery update/deletes, only way is slow per-row operations.
 # This assumes you have set proper transaction isolation and use innodb.
-sub subq_update_delete {
+sub _subq_update_delete {
   return shift->_per_row_update_delete (@_);
 }
 
+# MySql chokes on things like:
+# COUNT(*) FROM (SELECT tab1.col, tab2.col FROM tab1 JOIN tab2 ... )
+# claiming that col is a duplicate column (it loses the table specifiers by
+# the time it gets to the *). Thus for any subquery count we select only the
+# primary keys of the main table in the inner query. This hopefully still
+# hits the indexes and keeps mysql happy.
+# (mysql does not care if the SELECT and the GROUP BY match)
+sub _grouped_count_select {
+  my ($self, $source, $rs_args) = @_;
+  my @pcols = map { join '.', $rs_args->{alias}, $_ } ($source->primary_columns);
+  return @pcols ? \@pcols : $rs_args->{group_by};
+}
+
 1;
 
 =head1 NAME

diff --git a/t/71mysql.t b/t/71mysql.t
index cf02a61..d8254db 100644 (file)
--- a/t/71mysql.t
+++ b/t/71mysql.t
@@ -14,7 +14,7 @@ my ($dsn, $user, $pass) = @ENV{map { "DBICTEST_MYSQL_${_}" } qw/DSN USER PASS/};
 plan skip_all => 'Set $ENV{DBICTEST_MYSQL_DSN}, _USER and _PASS to run this test'
   unless ($dsn && $user);
 
-plan tests => 23;
+plan tests => 19;
 
 my $schema = DBICTest::Schema->connect($dsn, $user, $pass);
 
@@ -122,41 +122,19 @@ SKIP: {
   );
   my $owners2 = $schema->resultset ('Owners')->search ({ id => { -in => $owners->get_column ('me.id')->as_query }});
   for ($owners, $owners2) {
-    lives_ok { is ($_->all, 2, 'Prefetched grouped search returns correct number of rows') }
-      || skip ('No test due to exception', 1);
-    lives_ok { is ($_->count, 2, 'Prefetched grouped search returns correct count') }
-      || skip ('No test due to exception', 1);
+    is ($_->all, 2, 'Prefetched grouped search returns correct number of rows');
+    is ($_->count, 2, 'Prefetched grouped search returns correct count');
   }
 
-  TODO: {
-    # try a ->prefetch direction (no select collapse)
-    my $books = $schema->resultset ('BooksInLibrary')->search (
-      { 'owner.name' => 'wiggle' },
-      { prefetch => 'owner', distinct => 1 }
-    );
-
-    local $TODO = 'MySQL is crazy - there seems to be no way to make this work';
-    # error thrown is:
-    # Duplicate column name 'id' [for Statement "
-    #   SELECT COUNT( * )
-    #     FROM (
-    #       SELECT me.id, me.source, me.owner, me.title, me.price, owner.id, owner.name
-    #         FROM books me
-    #         JOIN owners owner ON owner.id = me.owner 
-    #       WHERE ( ( owner.name = ? AND source = ? ) ) 
-    #       GROUP BY me.id, me.source, me.owner, me.title, me.price, owner.id, owner.name
-    #     ) count_subq
-    # " with ParamValues: 0='wiggle', 1='Library']
-    #
-    # go fucking figure
-
-    my $books2 = $schema->resultset ('BooksInLibrary')->search ({ id => { -in => $books->get_column ('me.id')->as_query }});
-    for ($books, $books2) {
-      lives_ok { is ($_->all, 1, 'Prefetched grouped search returns correct number of rows') }
-        || skip ('No test due to exception', 1);
-      lives_ok { is ($_->count, 1, 'Prefetched grouped search returns correct count') }
-        || skip ('No test due to exception', 1);
-    }
+  # try a ->prefetch direction (no select collapse)
+  my $books = $schema->resultset ('BooksInLibrary')->search (
+    { 'owner.name' => 'wiggle' },
+    { prefetch => 'owner', distinct => 1 }
+  );
+  my $books2 = $schema->resultset ('BooksInLibrary')->search ({ id => { -in => $books->get_column ('me.id')->as_query }});
+  for ($books, $books2) {
+    is ($_->all, 1, 'Prefetched grouped search returns correct number of rows');
+    is ($_->count, 1, 'Prefetched grouped search returns correct count');
   }
 }