setName('db:index-usage')
->setDescription('Report unused database indexes (indexes that slow writes but are never read)')
->addOption('json', null, InputOption::VALUE_NONE, 'Output in JSON format')
->addOption('all', null, InputOption::VALUE_NONE, 'Show all indexes, not just unused ones');
}
#[\Override]
protected function execute(InputInterface $input, OutputInterface $output): int {
$platform = $this->connection->getDatabasePlatform();
$asJson = $input->getOption('json');
$showAll = $input->getOption('all');
if ($platform instanceof MySQLPlatform) {
// Requires performance_schema to be enabled (default in MySQL 5.6+/MariaDB 10.0+)
$unused_filter = $showAll ? '' : "WHERE s.count_read = 0 AND s.index_name IS NOT NULL AND s.index_name != 'PRIMARY'";
$sql = "SELECT s.object_name AS `table`,
s.index_name AS `index`,
s.count_read AS reads,
s.count_write AS writes
FROM performance_schema.table_io_waits_summary_by_index_usage s
{$unused_filter}
ORDER BY s.object_name, s.index_name";
} elseif ($platform instanceof PostgreSQLPlatform) {
$unused_filter = $showAll ? '' : 'AND idx_scan = 0';
$sql = "SELECT relname AS table,
indexrelname AS index,
idx_scan AS reads,
idx_tup_read AS tuples_read,
idx_tup_fetch AS tuples_fetched
FROM pg_stat_user_indexes
JOIN pg_index USING (indexrelid)
WHERE indisunique IS FALSE
{$unused_filter}
ORDER BY relname, indexrelname";
} else {
$output->writeln('db:index-usage is not supported for SQLite and Oracle.');
return Command::SUCCESS;
}
try {
$rows = $this->connection->executeQuery($sql)->fetchAllAssociative();
} catch (\Doctrine\DBAL\Exception $e) {
$output->writeln('Failed to query index usage statistics. The required performance tables may not be available on this database version.');
$output->writeln('Details: ' . $e->getMessage() . '');
return Command::FAILURE;
}
if (empty($rows)) {
$output->writeln('No unused indexes found. Great!');
return Command::SUCCESS;
}
if ($asJson) {
$output->writeln(json_encode($rows, JSON_PRETTY_PRINT));
return Command::SUCCESS;
}
$table = new Table($output);
if ($platform instanceof MySQLPlatform) {
$table->setHeaders(['Table', 'Index', 'Reads', 'Writes']);
foreach ($rows as $row) {
$table->addRow([$row['table'], $row['index'], $row['reads'], $row['writes']]);
}
} else {
$table->setHeaders(['Table', 'Index', 'Scans', 'Tuples Read', 'Tuples Fetched']);
foreach ($rows as $row) {
$table->addRow([$row['table'], $row['index'], $row['reads'], $row['tuples_read'], $row['tuples_fetched']]);
}
}
$table->render();
if (!$showAll) {
$output->writeln(sprintf(
'Found %d unused index(es). If those were not created by Nextcloud, consider removing them to improve write performance.',
count($rows)
));
}
return Command::SUCCESS;
}
}