diff options
| -rw-r--r-- | src/dbwrapper.h | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/src/dbwrapper.h b/src/dbwrapper.h index b13e98b7a4..442f37b420 100644 --- a/src/dbwrapper.h +++ b/src/dbwrapper.h @@ -55,11 +55,19 @@ private: CDataStream ssKey; CDataStream ssValue; + size_t size_estimate; + public: /** * @param[in] _parent CDBWrapper that this batch is to be submitted to */ - CDBBatch(const CDBWrapper &_parent) : parent(_parent), ssKey(SER_DISK, CLIENT_VERSION), ssValue(SER_DISK, CLIENT_VERSION) { }; + CDBBatch(const CDBWrapper &_parent) : parent(_parent), ssKey(SER_DISK, CLIENT_VERSION), ssValue(SER_DISK, CLIENT_VERSION), size_estimate(0) { }; + + void Clear() + { + batch.Clear(); + size_estimate = 0; + } template <typename K, typename V> void Write(const K& key, const V& value) @@ -74,6 +82,14 @@ public: leveldb::Slice slValue(ssValue.data(), ssValue.size()); batch.Put(slKey, slValue); + // LevelDB serializes writes as: + // - byte: header + // - varint: key length (1 byte up to 127B, 2 bytes up to 16383B, ...) + // - byte[]: key + // - varint: value length + // - byte[]: value + // The formula below assumes the key and value are both less than 16k. + size_estimate += 3 + (slKey.size() > 127) + slKey.size() + (slValue.size() > 127) + slValue.size(); ssKey.clear(); ssValue.clear(); } @@ -86,8 +102,16 @@ public: leveldb::Slice slKey(ssKey.data(), ssKey.size()); batch.Delete(slKey); + // LevelDB serializes erases as: + // - byte: header + // - varint: key length + // - byte[]: key + // The formula below assumes the key is less than 16kB. + size_estimate += 2 + (slKey.size() > 127) + slKey.size(); ssKey.clear(); } + + size_t SizeEstimate() const { return size_estimate; } }; class CDBIterator |