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Merged
CarlSchwan merged 6 commits into from
Jul 28, 2026
Merged

perf(preview): Optimize retriving all previews from oc_filecache #62601

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c192331
perf(preview): Optimize retriving all previews from oc_filecache
CarlSchwan Jul 28, 2026
0525899
perf: Batch deletion of old file entries
CarlSchwan Jul 28, 2026
831d4a6
perf: Don't list items twice in the preview folder
CarlSchwan Jul 28, 2026
1ebd8e3
chore(preview): Add more tests for the preview migration job
CarlSchwan Jul 28, 2026
7e79fc0
refactor(Preview): Refactor tests to reduce code duplication
CarlSchwan Jul 28, 2026
64cdaba
fix(Preview): Fix sharding of the PreviewMigrationService
CarlSchwan Jul 28, 2026
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105 changes: 43 additions & 62 deletions core/BackgroundJobs/PreviewMigrationJob.php
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Original file line number Diff line number Diff line change
Expand Up @@ -12,11 +12,10 @@
use OC\Preview\PreviewMigrationService;
use OCP\AppFramework\Utility\ITimeFactory;
use OCP\BackgroundJob\TimedJob;
use OCP\DB\IResult;
use OCP\Files\FileInfo;
use OCP\Files\IRootFolder;
use OCP\IAppConfig;
use OCP\IConfig;
use OCP\IDBConnection;
use Override;
use Psr\Log\LoggerInterface;

Expand All @@ -27,7 +26,6 @@ public function __construct(
ITimeFactory $time,
private readonly IAppConfig $appConfig,
private readonly IConfig $config,
private readonly IDBConnection $connection,
private readonly IRootFolder $rootFolder,
private readonly PreviewMigrationService $migrationService,
private readonly LoggerInterface $logger,
Expand All @@ -45,79 +43,62 @@ protected function run(mixed $argument): void {
return;
}

$startTime = time();
while (true) {
$qb = $this->connection->getQueryBuilder();
$qb->select('path')
->from('filecache')
->where($qb->expr()->orX(
// Hierarchical preview folder structure
$qb->expr()->like('path', $qb->createNamedParameter($this->previewRootPath . '%/%/%/%/%/%/%/%/%')),
// Legacy flat preview folder structure
$qb->expr()->like('path', $qb->createNamedParameter($this->previewRootPath . '%/%.%'))
))->andWhere(
$qb->expr()->eq('storage', $qb->createNamedParameter($this->rootFolder->getMountPoint()->getNumericStorageId()))
)
->hintShardKey('storage', $this->rootFolder->getMountPoint()->getNumericStorageId())
->setMaxResults(100);

$result = $qb->executeQuery();
$foundPreviews = $this->processQueryResult($result);

if (!$foundPreviews) {
break;
}
$storage = $this->rootFolder->getMountPoint()->getStorage();
if ($storage === null) {
$this->appConfig->setValueBool('core', 'previewMovedDone', true);
return;
}

// Stop if execution time is more than one hour.
if (time() - $startTime > 3600) {
return;
}
$cache = $storage->getCache();
$previewRootId = $cache->getId(rtrim($this->previewRootPath, '/'));
if ($previewRootId === -1) {
// No previews have ever been generated on this instance.
$this->appConfig->setValueBool('core', 'previewMovedDone', true);
return;
}

$this->appConfig->setValueBool('core', 'previewMovedDone', true);
}
$startTime = time();

private function processQueryResult(IResult $result): bool {
$foundPreview = false;
$fileIds = [];
$flatFileIds = [];
while ($row = $result->fetch()) {
$pathSplit = explode('/', $row['path']);
assert(count($pathSplit) >= 2);
$fileId = (int)$pathSplit[count($pathSplit) - 2];
if (count($pathSplit) === 11) {
// Hierarchical structure
if (!in_array($fileId, $fileIds)) {
$fileIds[] = $fileId;
}
} else {
// Flat structure
if (!in_array($fileId, $flatFileIds)) {
$flatFileIds[] = $fileId;
// Walk the preview folder tree via the `parent` column, which is indexed on
// every supported database platform.
//
// Depth from the preview root tells us which structure a leaf folder holds:
// - depth 1: legacy flat structure, e.g. preview/<fileid>/<size>.png
// - depth 8: hierarchical structure, e.g. preview/a/b/c/d/e/f/g/<fileid>/<size>.png
$foldersToVisit = [[$previewRootId, '', 0]];

while ($foldersToVisit !== []) {
[$folderId, $folderName, $depth] = array_pop($foldersToVisit);

// Collect the actual preview files here so migrateFileId() doesn't need to
// list this folder's contents a second time.
$previewEntries = [];
foreach ($cache->getFolderContentsById($folderId) as $entry) {
if ($entry->getMimeType() === FileInfo::MIMETYPE_FOLDER) {
$foldersToVisit[] = [$entry->getId(), $entry->getName(), $depth + 1];
} else {
$previewEntries[] = $entry;
}
}
$foundPreview = true;
}

foreach ($fileIds as $fileId) {
try {
$this->migrationService->migrateFileId($fileId, flatPath: false);
} catch (\Exception $e) {
$this->logger->error('Failed to migrate preview with fileId: ' . $fileId . ' (hierarchical file structure)', [
'exception' => $e,
]);
if ($previewEntries === [] || !ctype_digit($folderName)) {
continue;
}
}

foreach ($flatFileIds as $fileId) {
try {
$this->migrationService->migrateFileId($fileId, flatPath: true);
$this->migrationService->migrateFileId((int)$folderName, flatPath: $depth === 1, entries: $previewEntries);
} catch (\Exception $e) {
$this->logger->error('Failed to migrate preview with fileId: ' . $fileId . ' (legacy file structure)', [
$this->logger->error('Failed to migrate preview with fileId: ' . $folderName, [
'exception' => $e,
]);
}

// Stop if execution time is more than one hour.
if (time() - $startTime > 3600) {
return;
}
}
return $foundPreview;

$this->appConfig->setValueBool('core', 'previewMovedDone', true);
}
}
165 changes: 101 additions & 64 deletions lib/private/Preview/PreviewMigrationService.php
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,9 @@
use OC\Preview\Db\PreviewMapper;
use OC\Preview\Storage\StorageFactory;
use OCP\DB\Exception;
use OCP\DB\QueryBuilder\IQueryBuilder;
use OCP\Files\AppData\IAppDataFactory;
use OCP\Files\Cache\ICacheEntry;
use OCP\Files\IAppData;
use OCP\Files\IMimeTypeDetector;
use OCP\Files\IMimeTypeLoader;
Expand Down Expand Up @@ -44,44 +46,43 @@ public function __construct(
}

/**
* @param array<string|int, string[]> $previewFolders
* @param list<ICacheEntry|SimpleFile>|null $entries Preview file entries already fetched by the caller.
* @return Preview[]
*/
public function migrateFileId(int $fileId, bool $flatPath): array {
public function migrateFileId(int $fileId, bool $flatPath, ?array $entries = null): array {
$previews = [];
$internalPath = $this->getInternalFolder((string)$fileId, $flatPath);
try {
$folder = $this->appData->getFolder($internalPath);
} catch (NotFoundException) {
return [];

if ($entries === null) {
try {
$entries = $this->appData->getFolder($internalPath)->getDirectoryListing();
} catch (NotFoundException) {
return [];
}
}

/**
* @var list<array{file: SimpleFile, preview: Preview}> $previewFiles
* @var list<Preview> $previewsToInsert
*/
$previewFiles = [];
$previewsToInsert = [];

foreach ($folder->getDirectoryListing() as $previewFile) {
$path = $fileId . '/' . $previewFile->getName();
/** @var SimpleFile $previewFile */
foreach ($entries as $entry) {
$path = $fileId . '/' . $entry->getName();
$preview = Preview::fromPath($path, $this->mimeTypeDetector);
if ($preview === false) {
$this->logger->error('Unable to import old preview at path.');
continue;
}
$preview->generateId();
$preview->setSize($previewFile->getSize());
$preview->setMtime($previewFile->getMtime());
$preview->setOldFileId($previewFile->getId());
$preview->setSize($entry->getSize());
$preview->setMtime($entry->getMTime());
$preview->setOldFileId($entry->getId());
$preview->setEncrypted(false);

$previewFiles[] = [
'file' => $previewFile,
'preview' => $preview,
];
$previewsToInsert[] = $preview;
}

if (empty($previewFiles)) {
if (empty($previewsToInsert)) {
$this->deleteFolder($internalPath);

return $previews;
Expand All @@ -98,56 +99,51 @@ public function migrateFileId(int $fileId, bool $flatPath): array {
$cursor->closeCursor();

if ($result !== false) {
foreach ($previewFiles as $previewFile) {
/** @var Preview $preview */
$preview = $previewFile['preview'];
/** @var SimpleFile $file */
$file = $previewFile['file'];
$preview->setStorageId($result['storage']);
$preview->setEtag($result['etag']);
$preview->setSourceMimeType($this->mimeTypeLoader->getMimetypeById((int)$result['mimetype']));
$preview->generateId();
try {
$preview = $this->previewMapper->insert($preview);
} catch (Exception $e) {
if ($e->getReason() !== Exception::REASON_UNIQUE_CONSTRAINT_VIOLATION) {
throw $e;
$oldFileIdsToDelete = [];
try {
foreach ($previewsToInsert as $preview) {
$preview->setStorageId($result['storage']);
$preview->setEtag($result['etag']);
$preview->setSourceMimeType($this->mimeTypeLoader->getMimetypeById((int)$result['mimetype']));
$preview->generateId();
try {
$preview = $this->previewMapper->insert($preview);
} catch (Exception $e) {
if ($e->getReason() !== Exception::REASON_UNIQUE_CONSTRAINT_VIOLATION) {
throw $e;
}

// We already have this preview in the preview table, skip
$oldFileIdsToDelete[] = $preview->getOldFileId();
continue;
}

$delete = $this->connection->getQueryBuilder();
// We already have this preview in the preview table, skip
$delete->delete('filecache')
->where($delete->expr()->eq('fileid', $delete->createNamedParameter($file->getId())))
->hintShardKey('storage', $this->rootFolder->getMountPoint()->getNumericStorageId())
->executeStatement();
continue;
}
try {
$this->storageFactory->migratePreview($preview);
// Do not delete the old file via a Node here, as that would also
// delete it from the file system; only its filecache row is stale.
} catch (\Exception $e) {
$this->previewMapper->delete($preview);
throw $e;
}

try {
$this->storageFactory->migratePreview($preview, $file);
$qb = $this->connection->getQueryBuilder();
$qb->delete('filecache')
->where($qb->expr()->eq('fileid', $qb->createNamedParameter($file->getId())))
->hintShardKey('storage', $this->rootFolder->getMountPoint()->getNumericStorageId())
->executeStatement();
// Do not call $file->delete() as this will also delete the file from the file system
} catch (\Exception $e) {
$this->previewMapper->delete($preview);
throw $e;
$oldFileIdsToDelete[] = $preview->getOldFileId();
$previews[] = $preview;
}

$previews[] = $preview;
} finally {
$this->deleteOldFileCacheEntries($oldFileIdsToDelete);
}
} else {
// No matching fileId, delete preview
// No matching fileId, delete the orphaned preview files themselves.
try {
$folder = $this->appData->getFolder($internalPath);
$this->connection->beginTransaction();
foreach ($previewFiles as $previewFile) {
/** @var SimpleFile $file */
$file = $previewFile['file'];
foreach ($folder->getDirectoryListing() as $file) {
$file->delete();
}
$this->connection->commit();
} catch (NotFoundException) {
// Folder already gone, nothing to clean up.
} catch (Exception) {
$this->connection->rollback();
}
Expand All @@ -165,6 +161,23 @@ private static function getInternalFolder(string $name, bool $flatPath): string
return implode('/', str_split(substr(md5($name), 0, 7))) . '/' . $name;
}

/**
* @param list<int> $fileIds
*/
private function deleteOldFileCacheEntries(array $fileIds): void {
if ($fileIds === []) {
return;
}

foreach (array_chunk($fileIds, 1000) as $chunk) {
$qb = $this->connection->getQueryBuilder();
$qb->delete('filecache')
->where($qb->expr()->in('fileid', $qb->createNamedParameter($chunk, IQueryBuilder::PARAM_INT_ARRAY)))
->hintShardKey('storage', $this->rootFolder->getMountPoint()->getNumericStorageId())
->executeStatement();
}
}

private function deleteFolder(string $path): void {
$current = $path;

Expand All @@ -185,14 +198,38 @@ private function deleteFolder(string $path): void {
break;
}

try {
$folder = $this->appData->getFolder($current);
} catch (NotFoundException) {
break;
}
if (count($folder->getDirectoryListing()) !== 0) {
if ($this->folderHasChildren($rootFolderId, $this->previewRootPath . $current)) {
break;
}
}
}

private function folderHasChildren(int $storageId, string $path): bool {
$qb = $this->connection->getQueryBuilder();
$qb->select('fileid')
->from('filecache')
->where($qb->expr()->eq('path_hash', $qb->createNamedParameter(md5($path))))
->andWhere($qb->expr()->eq('storage', $qb->createNamedParameter($storageId)))
->setMaxResults(1);
$cursor = $qb->executeQuery();
$folderId = $cursor->fetchOne();
$cursor->closeCursor();

if ($folderId === false) {
// The folder itself is already gone, nothing to check.
return false;
}

$qb = $this->connection->getQueryBuilder();
$qb->select('fileid')
->from('filecache')
->where($qb->expr()->eq('parent', $qb->createNamedParameter((int)$folderId)))
->andWhere($qb->expr()->eq('storage', $qb->createNamedParameter($storageId)))
->setMaxResults(1);
$cursor = $qb->executeQuery();
$hasChild = $cursor->fetchOne() !== false;
$cursor->closeCursor();

return $hasChild;
}
}
3 changes: 1 addition & 2 deletions lib/private/Preview/Storage/IPreviewStorage.php
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,6 @@
namespace OC\Preview\Storage;

use Exception;
use OC\Files\SimpleFS\SimpleFile;
use OC\Preview\Db\Preview;
use OCP\Files\NotFoundException;
use OCP\Files\NotPermittedException;
Expand Down Expand Up @@ -42,7 +41,7 @@ public function deletePreview(Preview $preview): void;
* To remove at some point
* @throws Exception
*/
public function migratePreview(Preview $preview, SimpleFile $file): void;
public function migratePreview(Preview $preview): void;

/**
* @throws NotPermittedException
Expand Down
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