Merge #10195: Switch chainstate db and cache to per-txout model

589827975 scripted-diff: various renames for per-utxo consistency (Pieter Wuille)
a5e02bc7f Increase travis unit test timeout (Pieter Wuille)
73de2c1ff Rename CCoinsCacheEntry::coins to coin (Pieter Wuille)
119e552f7 Merge CCoinsViewCache's GetOutputFor and AccessCoin (Pieter Wuille)
580b02309 [MOVEONLY] Move old CCoins class to txdb.cpp (Pieter Wuille)
8b25d2c0c Upgrade from per-tx database to per-txout (Pieter Wuille)
b2af357f3 Reduce reserved memory space for flushing (Pieter Wuille)
41aa5b79a Pack Coin more tightly (Pieter Wuille)
97072d668 Remove unused CCoins methods (Pieter Wuille)
ce23efaa5 Extend coins_tests (Pieter Wuille)
508307968 Switch CCoinsView and chainstate db from per-txid to per-txout (Pieter Wuille)
4ec0d9e79 Refactor GetUTXOStats in preparation for per-COutPoint iteration (Pieter Wuille)
13870b56f Replace CCoins-based CTxMemPool::pruneSpent with isSpent (Pieter Wuille)
05293f3cb Remove ModifyCoins/ModifyNewCoins (Pieter Wuille)
961e48397 Switch tests from ModifyCoins to AddCoin/SpendCoin (Pieter Wuille)
8b3868c1b Switch CScriptCheck to use Coin instead of CCoins (Pieter Wuille)
c87b957a3 Only pass things committed to by tx's witness hash to CScriptCheck (Matt Corallo)
f68cdfe92 Switch from per-tx to per-txout CCoinsViewCache methods in some places (Pieter Wuille)
000391132 Introduce new per-txout CCoinsViewCache functions (Pieter Wuille)
bd83111a0 Optimization: Coin&& to ApplyTxInUndo (Pieter Wuille)
cb2c7fdac Replace CTxInUndo with Coin (Pieter Wuille)
422634e2f Introduce Coin, a single unspent output (Pieter Wuille)
7d991b55d Store/allow tx metadata in all undo records (Pieter Wuille)
c3aa0c119 Report on-disk size in gettxoutsetinfo (Pieter Wuille)
d34242430 Remove/ignore tx version in utxo and undo (Pieter Wuille)
7e0032290 Add specialization of SipHash for 256 + 32 bit data (Pieter Wuille)
e484652fc Introduce CHashVerifier to hash read data (Pieter Wuille)
f54580e7e error() in disconnect for disk corruption, not inconsistency (Pieter Wuille)
e66dbde6d Add SizeEstimate to CDBBatch (Pieter Wuille)

Tree-SHA512: ce1fb1e40c77d38915cd02189fab7a8b125c7f44d425c85579d872c3bede3a437760997907c99d7b3017ced1c2de54b2ac7223d99d83a6658fe5ef61edef1de3

1 files changed, 41 insertions, 2 deletions

diff --git a/src/dbwrapper.h b/src/dbwrapper.h
index b13e98b7a4..24ef71bfbf 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
@@ -281,7 +305,22 @@ public:
      * Return true if the database managed by this class contains no entries.
      */
     bool IsEmpty();
+
+    template<typename K>
+    size_t EstimateSize(const K& key_begin, const K& key_end) const
+    {
+        CDataStream ssKey1(SER_DISK, CLIENT_VERSION), ssKey2(SER_DISK, CLIENT_VERSION);
+        ssKey1.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
+        ssKey2.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
+        ssKey1 << key_begin;
+        ssKey2 << key_end;
+        leveldb::Slice slKey1(ssKey1.data(), ssKey1.size());
+        leveldb::Slice slKey2(ssKey2.data(), ssKey2.size());
+        uint64_t size = 0;
+        leveldb::Range range(slKey1, slKey2);
+        pdb->GetApproximateSizes(&range, 1, &size);
+        return size;
+    }
 };
 
 #endif // BITCOIN_DBWRAPPER_H
-