From ec3b1ccd91ed7b29818b79863638a1f5b7302e8a Mon Sep 17 00:00:00 2001
From: Sijmen Schoon <me@sijmenschoon.nl>
Date: Sun, 17 Oct 2021 19:08:27 +0200
Subject: [PATCH 1/2] Limit parameter count per query in Cache.removeChildren

Signed-off-by: Sijmen Schoon <me@sijmenschoon.nl>
---
 lib/private/Files/Cache/Cache.php | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/lib/private/Files/Cache/Cache.php b/lib/private/Files/Cache/Cache.php
index 1c30a5953c6f0..4572217325a0f 100644
--- a/lib/private/Files/Cache/Cache.php
+++ b/lib/private/Files/Cache/Cache.php
@@ -587,10 +587,13 @@ private function removeChildren(ICacheEntry $entry) {
 				return $cacheEntry->getId();
 			}, $children);
 
-			$query = $this->getQueryBuilder();
-			$query->delete('filecache_extended')
-				->where($query->expr()->in('fileid', $query->createNamedParameter($childIds, IQueryBuilder::PARAM_INT_ARRAY)));
-			$query->execute();
+			$childIdChunks = array_chunk($childIds, 2048);
+			foreach ($childIdChunks as $childIdChunk) {
+				$query = $this->getQueryBuilder();
+				$query->delete('filecache_extended')
+					->where($query->expr()->in('fileid', $query->createNamedParameter($childIdChunk, IQueryBuilder::PARAM_INT_ARRAY)));
+				$query->execute();
+			}
 
 			/** @var ICacheEntry[] $childFolders */
 			$childFolders = array_filter($children, function ($child) {
@@ -602,10 +605,13 @@ private function removeChildren(ICacheEntry $entry) {
 			}
 		}
 
-		$query = $this->getQueryBuilder();
-		$query->delete('filecache')
-			->whereParentIn($parentIds);
-		$query->execute();
+		$parentIdChunks = array_chunk($parentIds, 2048);
+		foreach ($parentIdChunks as $parentIdChunk) {
+			$query = $this->getQueryBuilder();
+			$query->delete('filecache')
+				->whereParentIn($parentIdChunk);
+			$query->execute();
+		}
 	}
 
 	/**

From 071eda7baafbb57c8fb79bc3c639b508c1cb93b5 Mon Sep 17 00:00:00 2001
From: Sijmen Schoon <me@sijmenschoon.nl>
Date: Sun, 17 Oct 2021 20:52:38 +0200
Subject: [PATCH 2/2] Move query outside the loop and reduce chunk size to 1000

This involved changing CacheQueryBuilder\whereParentIn to take a
parameter name, renaming the function accordingly.

Signed-off-by: Sijmen Schoon <me@sijmenschoon.nl>
---
 lib/private/Files/Cache/Cache.php             | 22 ++++++++++---------
 lib/private/Files/Cache/CacheQueryBuilder.php |  4 ++--
 2 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/lib/private/Files/Cache/Cache.php b/lib/private/Files/Cache/Cache.php
index 4572217325a0f..5420fb73d7f9c 100644
--- a/lib/private/Files/Cache/Cache.php
+++ b/lib/private/Files/Cache/Cache.php
@@ -587,11 +587,12 @@ private function removeChildren(ICacheEntry $entry) {
 				return $cacheEntry->getId();
 			}, $children);
 
-			$childIdChunks = array_chunk($childIds, 2048);
-			foreach ($childIdChunks as $childIdChunk) {
-				$query = $this->getQueryBuilder();
-				$query->delete('filecache_extended')
-					->where($query->expr()->in('fileid', $query->createNamedParameter($childIdChunk, IQueryBuilder::PARAM_INT_ARRAY)));
+			$query = $this->getQueryBuilder();
+			$query->delete('filecache_extended')
+				->where($query->expr()->in('fileid', $query->createParameter('childIds')));
+			
+			foreach (array_chunk($childIds, 1000) as $childIdChunk) {
+				$query->setParameter('childIds', $childIdChunk, IQueryBuilder::PARAM_INT_ARRAY);
 				$query->execute();
 			}
 
@@ -605,11 +606,12 @@ private function removeChildren(ICacheEntry $entry) {
 			}
 		}
 
-		$parentIdChunks = array_chunk($parentIds, 2048);
-		foreach ($parentIdChunks as $parentIdChunk) {
-			$query = $this->getQueryBuilder();
-			$query->delete('filecache')
-				->whereParentIn($parentIdChunk);
+		$query = $this->getQueryBuilder();
+		$query->delete('filecache')
+			->whereParentInParameter('parentIds');
+
+		foreach (array_chunk($parentIds, 1000) as $parentIdChunk) {
+			$query->setParameter('parentIds', $parentIdChunk, IQueryBuilder::PARAM_INT_ARRAY);
 			$query->execute();
 		}
 	}
diff --git a/lib/private/Files/Cache/CacheQueryBuilder.php b/lib/private/Files/Cache/CacheQueryBuilder.php
index 774691ebc3189..87a1f940f2075 100644
--- a/lib/private/Files/Cache/CacheQueryBuilder.php
+++ b/lib/private/Files/Cache/CacheQueryBuilder.php
@@ -91,7 +91,7 @@ public function whereParent(int $parent) {
 		return $this;
 	}
 
-	public function whereParentIn(array $parents) {
+	public function whereParentInParameter(string $parameter) {
 		$alias = $this->alias;
 		if ($alias) {
 			$alias .= '.';
@@ -99,7 +99,7 @@ public function whereParentIn(array $parents) {
 			$alias = '';
 		}
 
-		$this->andWhere($this->expr()->in("{$alias}parent", $this->createNamedParameter($parents, IQueryBuilder::PARAM_INT_ARRAY)));
+		$this->andWhere($this->expr()->in("{$alias}parent", $this->createParameter($parameter)));
 
 		return $this;
 	}