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Unified Diff: content/browser/indexed_db/leveldb/leveldb_database.h

Issue 2760163002: [IndexedDB] Pool and evict leveldb iterators, to save memory (Closed)
Patch Set: comments Created 3 years, 9 months ago
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Index: content/browser/indexed_db/leveldb/leveldb_database.h
diff --git a/content/browser/indexed_db/leveldb/leveldb_database.h b/content/browser/indexed_db/leveldb/leveldb_database.h
index cdcabb54647c83c9d2f56690e2a84ba2fecd87c9..ab3800e4ac3f9fdd7677990a3b9cc6b400e71758 100644
--- a/content/browser/indexed_db/leveldb/leveldb_database.h
+++ b/content/browser/indexed_db/leveldb/leveldb_database.h
@@ -8,6 +8,7 @@
#include <memory>
#include <string>
+#include "base/containers/mru_cache.h"
#include "base/files/file_path.h"
#include "base/macros.h"
#include "base/strings/string16.h"
@@ -21,6 +22,7 @@ namespace leveldb {
class Comparator;
class DB;
class FilterPolicy;
+class Iterator;
class Env;
class Snapshot;
}
@@ -58,6 +60,10 @@ class CONTENT_EXPORT LevelDBLock {
class CONTENT_EXPORT LevelDBDatabase
: public base::trace_event::MemoryDumpProvider {
public:
+ // Necessary because every iterator hangs onto leveldb blocks which can be
+ // large. See https://crbug/696055.
+ static const size_t kDefaultMaxOpenIteratorsPerDatabase = 50;
+
class ComparatorAdapter : public leveldb::Comparator {
public:
explicit ComparatorAdapter(const LevelDBComparator* comparator);
@@ -75,10 +81,13 @@ class CONTENT_EXPORT LevelDBDatabase
const LevelDBComparator* comparator_;
};
+ // |max_open_cursors| cannot be 0.
static leveldb::Status Open(const base::FilePath& file_name,
const LevelDBComparator* comparator,
+ size_t max_open_cursors,
std::unique_ptr<LevelDBDatabase>* db,
bool* is_disk_full = 0);
+
static std::unique_ptr<LevelDBDatabase> OpenInMemory(
const LevelDBComparator* comparator);
static leveldb::Status Destroy(const base::FilePath& file_name);
@@ -103,10 +112,17 @@ class CONTENT_EXPORT LevelDBDatabase
base::trace_event::ProcessMemoryDump* pmd) override;
protected:
- LevelDBDatabase();
+ LevelDBDatabase(size_t max_open_iterators);
private:
friend class LevelDBSnapshot;
+ friend class LevelDBIteratorImpl;
+
+ // Methods for iterator pooling.
+ std::unique_ptr<leveldb::Iterator> CreateLevelDBIterator(
+ const leveldb::Snapshot*);
+ void OnIteratorUsed(LevelDBIterator*);
+ void OnIteratorDestroyed(LevelDBIterator*);
void CloseDatabase();
@@ -115,6 +131,31 @@ class CONTENT_EXPORT LevelDBDatabase
std::unique_ptr<leveldb::DB> db_;
std::unique_ptr<const leveldb::FilterPolicy> filter_policy_;
const LevelDBComparator* comparator_;
+
+ struct DetachIteratorOnDestruct {
+ DetachIteratorOnDestruct() {}
+ explicit DetachIteratorOnDestruct(LevelDBIterator* it) : it_(it) {}
+ DetachIteratorOnDestruct(DetachIteratorOnDestruct&& that) {
+ it_ = that.it_;
+ that.it_ = nullptr;
+ }
+ ~DetachIteratorOnDestruct();
+
+ private:
+ LevelDBIterator* it_ = nullptr;
+
+ DISALLOW_COPY_AND_ASSIGN(DetachIteratorOnDestruct);
+ };
+
+ // Despite the type name, this object uses LRU eviction.
+ size_t lru_max_size_ = 0;
+ base::HashingMRUCache<LevelDBIterator*, DetachIteratorOnDestruct>
+ iterator_lru_;
+
+ // Recorded for UMA reporting.
+ uint32_t num_iterators_ = 0;
+ uint32_t max_iterators_ = 0;
+
std::string file_name_for_tracing;
};

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