add better index for finding unindexed paths

for the following query 'SELECT "path" FROM "oc_filecache" WHERE ("storage" = $storage) AND ("size" < 0) ORDER BY "fileid" DESC LIMIT 1;'

currently the database will in some cases decide to priorize the sort by fileid over the filter when picking what index to use, resulting in a much slower query.

by creating an index that allows first sorting by fileid and also filter by storage and size this case will be greatly sped up

Signed-off-by: Robin Appelman <robin@icewind.nl>

core/Application.php

@@ -114,6 +114,10 @@ function (GenericEvent $event) use ($container) {
 					if (!$table->hasIndex('fs_size')) {
 						$subject->addHintForMissingSubject($table->getName(), 'fs_size');
 					}
+
+					if (!$table->hasIndex('fs_id_storage_size')) {
+						$subject->addHintForMissingSubject($table->getName(), 'fs_id_storage_size');
+					}
 				}
 
 				if ($schema->hasTable('twofactor_providers')) {

core/Command/Db/AddMissingIndices.php

@@ -144,6 +144,13 @@ private function addCoreIndexes(OutputInterface $output) {
 				$updated = true;
 				$output->writeln('<info>Filecache table updated successfully.</info>');
 			}
+			if (!$table->hasIndex('fs_id_storage_size')) {
+				$output->writeln('<info>Adding additional size index to the filecache table, this can take some time...</info>');
+				$table->addIndex(['fileid', 'storage', 'size'], 'fs_id_storage_size');
+				$this->connection->migrateToSchema($schema->getWrappedSchema());
+				$updated = true;
+				$output->writeln('<info>Filecache table updated successfully.</info>');
+			}
 		}
 
 		$output->writeln('<info>Check indices of the twofactor_providers table.</info>');

core/Migrations/Version13000Date20170718121200.php

@@ -261,6 +261,7 @@ public function changeSchema(IOutput $output, \Closure $schemaClosure, array $op
 			$table->addIndex(['storage', 'mimetype'], 'fs_storage_mimetype');
 			$table->addIndex(['storage', 'mimepart'], 'fs_storage_mimepart');
 			$table->addIndex(['storage', 'size', 'fileid'], 'fs_storage_size');
+			$table->addIndex(['fileid', 'storage', 'size'], 'fs_id_storage_size');
 			$table->addIndex(['mtime'], 'fs_mtime');
 			$table->addIndex(['size'], 'fs_size');
 		}