Improve performance of midgard_storage methods

[flack]

When I run this code

$re = new ReflectionExtension('midgard2');
$classes = $re->getClasses();
$counter = 0;
$start = microtime(true);
foreach ($classes as $refclass)
{
    if (!$refclass->isSubclassOf('midgard_object'))
    {
        continue;
    }
    $type = $refclass->getName();
    if (midgard_storage::class_storage_exists($type))
    {
        $counter++;
    }
}
echo "found " . $counter . " schema types in " . round(microtime(true) - $start, 2) . "s";

I get the following output:

found 85 schema types in 154,82s

This is on a quad-core Xeon machine with 5GB of RAM, so I don't think it's a hardware thing. Either midgard_storage or the reflection calls must be really slow. It would be nice if this could be improved, for developing, this gets quite tiresome.

[piotras]

Known problem :( Libgda is bottleneck here. It uses own database to provide tables metadata IIRC.

[flack]

But still, two seconds to check if a table exists is really a lot of time, it almost sounds as if it creates the metadata database on the fly for each method call. I wonder if some of the work it does couldn't be avoided somehow. BTW: If I call midgard_storage::class_storage_exists() twice per type in the loop, the runtime practically doubles (151s vs. 295s)