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Use fixed preallocation instead of costly GetSerializeSize

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Dbwrapper used GetSerializeSize() to compute the size of the buffer
to preallocate. For some cases (specifically: CCoins) this requires
a costly compression call. Avoid this by just using fixed size
preallocations instead.
This commit is contained in:
Pieter Wuille 2016-10-28 19:12:39 -07:00
parent 25a211aa9e
commit d59a518466
1 changed files with 9 additions and 6 deletions
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15
src/dbwrapper.h
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@ -17,6 +17,9 @@
#include <leveldb/db.h> #include <leveldb/db.h>
#include <leveldb/write_batch.h> #include <leveldb/write_batch.h>
static const size_t DBWRAPPER_PREALLOC_KEY_SIZE = 64;
static const size_t DBWRAPPER_PREALLOC_VALUE_SIZE = 1024;
class dbwrapper_error : public std::runtime_error class dbwrapper_error : public std::runtime_error
{ {
public: public:
@ -60,12 +63,12 @@ public:
void Write(const K& key, const V& value) void Write(const K& key, const V& value)
{ {
CDataStream ssKey(SER_DISK, CLIENT_VERSION); CDataStream ssKey(SER_DISK, CLIENT_VERSION);
ssKey.reserve(GetSerializeSize(ssKey, key)); ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
ssKey << key; ssKey << key;
leveldb::Slice slKey(&ssKey[0], ssKey.size()); leveldb::Slice slKey(&ssKey[0], ssKey.size());
CDataStream ssValue(SER_DISK, CLIENT_VERSION); CDataStream ssValue(SER_DISK, CLIENT_VERSION);
ssValue.reserve(GetSerializeSize(ssValue, value)); ssValue.reserve(DBWRAPPER_PREALLOC_VALUE_SIZE);
ssValue << value; ssValue << value;
ssValue.Xor(dbwrapper_private::GetObfuscateKey(parent)); ssValue.Xor(dbwrapper_private::GetObfuscateKey(parent));
leveldb::Slice slValue(&ssValue[0], ssValue.size()); leveldb::Slice slValue(&ssValue[0], ssValue.size());
@ -77,7 +80,7 @@ public:
void Erase(const K& key) void Erase(const K& key)
{ {
CDataStream ssKey(SER_DISK, CLIENT_VERSION); CDataStream ssKey(SER_DISK, CLIENT_VERSION);
ssKey.reserve(GetSerializeSize(ssKey, key)); ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
ssKey << key; ssKey << key;
leveldb::Slice slKey(&ssKey[0], ssKey.size()); leveldb::Slice slKey(&ssKey[0], ssKey.size());
@ -107,7 +110,7 @@ public:
template<typename K> void Seek(const K& key) { template<typename K> void Seek(const K& key) {
CDataStream ssKey(SER_DISK, CLIENT_VERSION); CDataStream ssKey(SER_DISK, CLIENT_VERSION);
ssKey.reserve(GetSerializeSize(ssKey, key)); ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
ssKey << key; ssKey << key;
leveldb::Slice slKey(&ssKey[0], ssKey.size()); leveldb::Slice slKey(&ssKey[0], ssKey.size());
piter->Seek(slKey); piter->Seek(slKey);
@ -200,7 +203,7 @@ public:
bool Read(const K& key, V& value) const bool Read(const K& key, V& value) const
{ {
CDataStream ssKey(SER_DISK, CLIENT_VERSION); CDataStream ssKey(SER_DISK, CLIENT_VERSION);
ssKey.reserve(GetSerializeSize(ssKey, key)); ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
ssKey << key; ssKey << key;
leveldb::Slice slKey(&ssKey[0], ssKey.size()); leveldb::Slice slKey(&ssKey[0], ssKey.size());
@ -234,7 +237,7 @@ public:
bool Exists(const K& key) const bool Exists(const K& key) const
{ {
CDataStream ssKey(SER_DISK, CLIENT_VERSION); CDataStream ssKey(SER_DISK, CLIENT_VERSION);
ssKey.reserve(GetSerializeSize(ssKey, key)); ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
ssKey << key; ssKey << key;
leveldb::Slice slKey(&ssKey[0], ssKey.size()); leveldb::Slice slKey(&ssKey[0], ssKey.size());