ClickHouse/dbms/src/Interpreters/AggregationCommon.h
2018-09-28 13:44:59 +03:00

247 lines
7.3 KiB
C++

#pragma once
#include <array>
#include <Common/SipHash.h>
#include <Common/Arena.h>
#include <Common/UInt128.h>
#include <Common/HashTable/Hash.h>
#include <Common/memcpySmall.h>
#include <Core/Defines.h>
#include <common/StringRef.h>
#include <Columns/IColumn.h>
#include <Columns/ColumnsNumber.h>
#include <Columns/ColumnFixedString.h>
#include <Columns/ColumnLowCardinality.h>
template <>
struct DefaultHash<StringRef> : public StringRefHash {};
namespace DB
{
using Sizes = std::vector<size_t>;
/// When packing the values of nullable columns at a given row, we have to
/// store the fact that these values are nullable or not. This is achieved
/// by encoding this information as a bitmap. Let S be the size in bytes of
/// a packed values binary blob and T the number of bytes we may place into
/// this blob, the size that the bitmap shall occupy in the blob is equal to:
/// ceil(T/8). Thus we must have: S = T + ceil(T/8). Below we indicate for
/// each value of S, the corresponding value of T, and the bitmap size:
///
/// 32,28,4
/// 16,14,2
/// 8,7,1
/// 4,3,1
/// 2,1,1
///
namespace
{
template <typename T>
constexpr auto getBitmapSize()
{
return
(sizeof(T) == 32) ?
4 :
(sizeof(T) == 16) ?
2 :
((sizeof(T) == 8) ?
1 :
((sizeof(T) == 4) ?
1 :
((sizeof(T) == 2) ?
1 :
0)));
}
}
template <typename T>
using KeysNullMap = std::array<UInt8, getBitmapSize<T>()>;
/// Pack into a binary blob of type T a set of fixed-size keys. Granted that all the keys fit into the
/// binary blob, they are disposed in it consecutively.
template <typename T, bool has_low_cardinality = false>
static inline T ALWAYS_INLINE packFixed(
size_t i, size_t keys_size, const ColumnRawPtrs & key_columns, const Sizes & key_sizes,
const ColumnRawPtrs * low_cardinality_positions [[maybe_unused]] = nullptr,
const Sizes * low_cardinality_sizes [[maybe_unused]] = nullptr)
{
union
{
T key;
char bytes[sizeof(key)] = {};
};
size_t offset = 0;
for (size_t j = 0; j < keys_size; ++j)
{
size_t index = i;
const IColumn * column = key_columns[j];
if constexpr (has_low_cardinality)
{
if (const IColumn * positions = (*low_cardinality_positions)[j])
{
switch ((*low_cardinality_sizes)[j])
{
case sizeof(UInt8): index = static_cast<const ColumnUInt8 *>(positions)->getElement(i); break;
case sizeof(UInt16): index = static_cast<const ColumnUInt16 *>(positions)->getElement(i); break;
case sizeof(UInt32): index = static_cast<const ColumnUInt32 *>(positions)->getElement(i); break;
case sizeof(UInt64): index = static_cast<const ColumnUInt64 *>(positions)->getElement(i); break;
default: throw Exception("Unexpected size of index type for low cardinality column.", ErrorCodes::LOGICAL_ERROR);
}
}
}
switch (key_sizes[j])
{
case 1:
memcpy(bytes + offset, &static_cast<const ColumnUInt8 *>(column)->getData()[index], 1);
offset += 1;
break;
case 2:
memcpy(bytes + offset, &static_cast<const ColumnUInt16 *>(column)->getData()[index], 2);
offset += 2;
break;
case 4:
memcpy(bytes + offset, &static_cast<const ColumnUInt32 *>(column)->getData()[index], 4);
offset += 4;
break;
case 8:
memcpy(bytes + offset, &static_cast<const ColumnUInt64 *>(column)->getData()[index], 8);
offset += 8;
break;
default:
memcpy(bytes + offset, &static_cast<const ColumnFixedString *>(column)->getChars()[index * key_sizes[j]], key_sizes[j]);
offset += key_sizes[j];
}
}
return key;
}
/// Similar as above but supports nullable values.
template <typename T>
static inline T ALWAYS_INLINE packFixed(
size_t i, size_t keys_size, const ColumnRawPtrs & key_columns, const Sizes & key_sizes,
const KeysNullMap<T> & bitmap)
{
union
{
T key;
char bytes[sizeof(key)] = {};
};
size_t offset = 0;
static constexpr auto bitmap_size = std::tuple_size<KeysNullMap<T>>::value;
static constexpr bool has_bitmap = bitmap_size > 0;
if (has_bitmap)
{
memcpy(bytes + offset, bitmap.data(), bitmap_size * sizeof(UInt8));
offset += bitmap_size;
}
for (size_t j = 0; j < keys_size; ++j)
{
bool is_null;
if (!has_bitmap)
is_null = false;
else
{
size_t bucket = j / 8;
size_t off = j % 8;
is_null = ((bitmap[bucket] >> off) & 1) == 1;
}
if (is_null)
continue;
switch (key_sizes[j])
{
case 1:
memcpy(bytes + offset, &static_cast<const ColumnUInt8 *>(key_columns[j])->getData()[i], 1);
offset += 1;
break;
case 2:
memcpy(bytes + offset, &static_cast<const ColumnUInt16 *>(key_columns[j])->getData()[i], 2);
offset += 2;
break;
case 4:
memcpy(bytes + offset, &static_cast<const ColumnUInt32 *>(key_columns[j])->getData()[i], 4);
offset += 4;
break;
case 8:
memcpy(bytes + offset, &static_cast<const ColumnUInt64 *>(key_columns[j])->getData()[i], 8);
offset += 8;
break;
default:
memcpy(bytes + offset, &static_cast<const ColumnFixedString *>(key_columns[j])->getChars()[i * key_sizes[j]], key_sizes[j]);
offset += key_sizes[j];
}
}
return key;
}
/// Hash a set of keys into a UInt128 value.
static inline UInt128 ALWAYS_INLINE hash128(
size_t i, size_t keys_size, const ColumnRawPtrs & key_columns)
{
UInt128 key;
SipHash hash;
for (size_t j = 0; j < keys_size; ++j)
key_columns[j]->updateHashWithValue(i, hash);
hash.get128(key.low, key.high);
return key;
}
/// Copy keys to the pool. Then put into pool StringRefs to them and return the pointer to the first.
static inline StringRef * ALWAYS_INLINE placeKeysInPool(
size_t keys_size, StringRefs & keys, Arena & pool)
{
for (size_t j = 0; j < keys_size; ++j)
{
char * place = pool.alloc(keys[j].size);
memcpySmallAllowReadWriteOverflow15(place, keys[j].data, keys[j].size);
keys[j].data = place;
}
/// Place the StringRefs on the newly copied keys in the pool.
char * res = pool.alignedAlloc(keys_size * sizeof(StringRef), alignof(StringRef));
memcpySmallAllowReadWriteOverflow15(res, keys.data(), keys_size * sizeof(StringRef));
return reinterpret_cast<StringRef *>(res);
}
/** Serialize keys into a continuous chunk of memory.
*/
static inline StringRef ALWAYS_INLINE serializeKeysToPoolContiguous(
size_t i, size_t keys_size, const ColumnRawPtrs & key_columns, Arena & pool)
{
const char * begin = nullptr;
size_t sum_size = 0;
for (size_t j = 0; j < keys_size; ++j)
sum_size += key_columns[j]->serializeValueIntoArena(i, pool, begin).size;
return {begin, sum_size};
}
}