diff --git a/lib/Db/BoardMapper.php b/lib/Db/BoardMapper.php
index 25a671f1c..c340aa151 100644
--- a/lib/Db/BoardMapper.php
+++ b/lib/Db/BoardMapper.php
@@ -107,6 +107,47 @@ class BoardMapper extends QBMapper implements IPermissionMapper {
 		return $this->boardCache[$id];
 	}
 
+	public function findBoardIds(string $userId): array {
+		$qb = $this->db->getQueryBuilder();
+		$qb->selectDistinct('b.id')
+			->from($this->getTableName(), 'b')
+			->leftJoin('b', 'deck_board_acl', 'acl', $qb->expr()->eq('b.id', 'acl.board_id'));
+
+		// Owned by the user
+		$qb->where($qb->expr()->andX(
+			$qb->expr()->eq('owner', $qb->createNamedParameter($userId, IQueryBuilder::PARAM_STR)),
+		));
+
+		// Shared to the user
+		$qb->orWhere($qb->expr()->andX(
+			$qb->expr()->eq('acl.participant', $qb->createNamedParameter($userId, IQueryBuilder::PARAM_STR)),
+			$qb->expr()->eq('acl.type', $qb->createNamedParameter(Acl::PERMISSION_TYPE_USER, IQueryBuilder::PARAM_INT)),
+		));
+
+		// Shared to user groups of the user
+		$groupIds = $this->groupManager->getUserGroupIds($this->userManager->get($userId));
+		if (count($groupIds) !== 0) {
+			$qb->orWhere($qb->expr()->andX(
+					$qb->expr()->in('acl.participant', $qb->createNamedParameter($groupIds, IQueryBuilder::PARAM_STR_ARRAY)),
+					$qb->expr()->eq('acl.type', $qb->createNamedParameter(Acl::PERMISSION_TYPE_GROUP, IQueryBuilder::PARAM_INT)),
+				));
+		}
+
+		// Shared to circles of the user
+		$circles = $this->circlesService->getUserCircles($userId);
+		if (count($circles) !== 0) {
+			$qb->orWhere($qb->expr()->andX(
+				$qb->expr()->in('acl.participant', $qb->createNamedParameter($circles, IQueryBuilder::PARAM_STR_ARRAY)),
+				$qb->expr()->eq('acl.type', $qb->createNamedParameter(Acl::PERMISSION_TYPE_CIRCLE, IQueryBuilder::PARAM_INT)),
+			));
+		}
+
+		$result = $qb->executeQuery();
+		return array_map(function (string $id) {
+			return (int)$id;
+		}, $result->fetchAll(\PDO::FETCH_COLUMN));
+	}
+
 	public function findAllForUser(string $userId, ?int $since = null, bool $includeArchived = true, ?int $before = null,
 								   ?string $term = null): array {
 		$useCache = ($since === -1 && $includeArchived === true && $before === null && $term === null);
diff --git a/lib/Sharing/DeckShareProvider.php b/lib/Sharing/DeckShareProvider.php
index 6e4bec244..483e68557 100644
--- a/lib/Sharing/DeckShareProvider.php
+++ b/lib/Sharing/DeckShareProvider.php
@@ -634,8 +634,8 @@ class DeckShareProvider implements \OCP\Share\IShareProvider {
 		$start = 0;
 		while (true) {
 			/** @var IShare[] $shareSlice */
-			$shareSlice = array_slice($shares, $start, 100);
-			$start += 100;
+			$shareSlice = array_slice($shares, $start, 1000);
+			$start += 1000;
 
 			if ($shareSlice === []) {
 				break;
@@ -714,15 +714,15 @@ class DeckShareProvider implements \OCP\Share\IShareProvider {
 	 * @return IShare[]
 	 */
 	public function getSharedWith($userId, $shareType, $node, $limit, $offset): array {
-		$allBoards = $this->boardMapper->findAllForUser($userId);
+		$allBoards = $this->boardMapper->findBoardIds($userId);
 
 		/** @var IShare[] $shares */
 		$shares = [];
 
 		$start = 0;
 		while (true) {
-			$boards = array_slice($allBoards, $start, 100);
-			$start += 100;
+			$boards = array_slice($allBoards, $start, 1000);
+			$start += 1000;
 
 			if ($boards === []) {
 				break;
@@ -752,10 +752,6 @@ class DeckShareProvider implements \OCP\Share\IShareProvider {
 				$qb->andWhere($qb->expr()->eq('s.file_source', $qb->createNamedParameter($node->getId())));
 			}
 
-			$boards = array_map(function (Board $board) {
-				return $board->getId();
-			}, $boards);
-
 			$qb->andWhere($qb->expr()->eq('s.share_type', $qb->createNamedParameter(IShare::TYPE_DECK)))
 				->andWhere($qb->expr()->in('db.id', $qb->createNamedParameter(
 					$boards,