fix: Avoid too large index on postgres as indexing just the last_edit…

…or column is enough

Signed-off-by: Julius Härtl <[email protected]>

lib/Db/CardMapper.php

@@ -306,8 +306,7 @@ public function findUnexposedDescriptionChances() {
 		$qb = $this->db->getQueryBuilder();
 		$qb->select('id', 'title', 'duedate', 'notified', 'description_prev', 'last_editor', 'description')
 			->from('deck_cards')
-			->where($qb->expr()->isNotNull('last_editor'))
-			->andWhere($qb->expr()->isNotNull('description_prev'));
+			->where($qb->expr()->isNotNull('last_editor'));
 		return $this->findEntities($qb);
 	}
 

lib/Migration/Version1011Date20231106160059.php

@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2023 Your name <[email protected]>
+ *
+ * @author Your name <[email protected]>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\Deck\Migration;
+
+use Closure;
+use OCP\DB\ISchemaWrapper;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+class Version1011Date20231106160059 extends SimpleMigrationStep {
+
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		$schema = $schemaClosure();
+
+		$createIndex = false;
+
+		$table = $schema->getTable('deck_cards');
+
+		if (!$table->hasIndex('idx_last_editor')) {
+			$createIndex = true;
+		}
+
+		if (!$createIndex) {
+			$index = $table->getIndex('idx_last_editor');
+			if (in_array('description_prev', $index->getColumns(), true)) {
+				$table->dropIndex('idx_last_editor');
+				$createIndex = true;
+			}
+		}
+
+		if ($createIndex) {
+			$table->addIndex(['last_editor'], 'idx_last_editor');
+			return $schema;
+		}
+
+		return null;
+	}
+}

lib/Migration/Version10800Date20220422061816.php

@@ -66,7 +66,7 @@ public function changeSchema(IOutput $output, Closure $schemaClosure, array $opt
 		$indexAdded = $this->addIndex($schema,
 			'deck_cards',
 			'idx_last_editor', [
-				'last_editor', 'description_prev'
+				'last_editor' /*, 'description_prev' */
 			], [],
 			// Adding a partial index on the description_prev as it is only used for a NULL check
 			['lengths' => [null, 1]]