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ad5325a736
rocksdb/util/hash_test.cc
Peter Dillinger ad5325a736 Experimental support for SST unique IDs (#8990) 
Summary:
* New public header unique_id.h and function GetUniqueIdFromTableProperties
which computes a universally unique identifier based on table properties
of table files from recent RocksDB versions.
* Generation of DB session IDs is refactored so that they are
guaranteed unique in the lifetime of a process running RocksDB.
(SemiStructuredUniqueIdGen, new test included.) Along with file numbers,
this enables SST unique IDs to be guaranteed unique among SSTs generated
in a single process, and "better than random" between processes.
See https://github.com/pdillinger/unique_id
* In addition to public API producing 'external' unique IDs, there is a function
for producing 'internal' unique IDs, with functions for converting between the
two. In short, the external ID is "safe" for things people might do with it, and
the internal ID enables more "power user" features for the future. Specifically,
the external ID goes through a hashing layer so that any subset of bits in the
external ID can be used as a hash of the full ID, while also preserving
uniqueness guarantees in the first 128 bits (bijective both on first 128 bits
and on full 192 bits).

Intended follow-up:
* Use the internal unique IDs in cache keys. (Avoid conflicts with https://github.com/facebook/rocksdb/issues/8912) (The file offset can be XORed into
the third 64-bit value of the unique ID.)
* Publish the external unique IDs in FileStorageInfo (https://github.com/facebook/rocksdb/issues/8968)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8990

Test Plan:
Unit tests added, and checking of unique ids in stress test.
NOTE in stress test we do not generate nearly enough files to thoroughly
stress uniqueness, but the test trims off pieces of the ID to check for
uniqueness so that we can infer (with some assumptions) stronger
properties in the aggregate.

Reviewed By: zhichao-cao, mrambacher

Differential Revision: D31582865

Pulled By: pdillinger

fbshipit-source-id: 1f620c4c86af9abe2a8d177b9ccf2ad2b9f48243
2021-10-18 23:32:01 -07:00

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2012 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "util/hash.h"
#include <cstring>
#include <vector>
#include "test_util/testharness.h"
#include "util/coding.h"
#include "util/coding_lean.h"
#include "util/hash128.h"
#include "util/math128.h"
using ROCKSDB_NAMESPACE::BijectiveHash2x64;
using ROCKSDB_NAMESPACE::BijectiveUnhash2x64;
using ROCKSDB_NAMESPACE::DecodeFixed64;
using ROCKSDB_NAMESPACE::EncodeFixed32;
using ROCKSDB_NAMESPACE::GetSliceHash64;
using ROCKSDB_NAMESPACE::Hash;
using ROCKSDB_NAMESPACE::Hash128;
using ROCKSDB_NAMESPACE::Hash2x64;
using ROCKSDB_NAMESPACE::Hash64;
using ROCKSDB_NAMESPACE::Lower32of64;
using ROCKSDB_NAMESPACE::Lower64of128;
using ROCKSDB_NAMESPACE::Slice;
using ROCKSDB_NAMESPACE::Unsigned128;
using ROCKSDB_NAMESPACE::Upper32of64;
using ROCKSDB_NAMESPACE::Upper64of128;
// The hash algorithm is part of the file format, for example for the Bloom
// filters. Test that the hash values are stable for a set of random strings of
// varying lengths.
TEST(HashTest, Values) {
constexpr uint32_t kSeed = 0xbc9f1d34; // Same as BloomHash.
EXPECT_EQ(Hash("", 0, kSeed), 3164544308u);
EXPECT_EQ(Hash("\x08", 1, kSeed), 422599524u);
EXPECT_EQ(Hash("\x17", 1, kSeed), 3168152998u);
EXPECT_EQ(Hash("\x9a", 1, kSeed), 3195034349u);
EXPECT_EQ(Hash("\x1c", 1, kSeed), 2651681383u);
EXPECT_EQ(Hash("\x4d\x76", 2, kSeed), 2447836956u);
EXPECT_EQ(Hash("\x52\xd5", 2, kSeed), 3854228105u);
EXPECT_EQ(Hash("\x91\xf7", 2, kSeed), 31066776u);
EXPECT_EQ(Hash("\xd6\x27", 2, kSeed), 1806091603u);
EXPECT_EQ(Hash("\x30\x46\x0b", 3, kSeed), 3808221797u);
EXPECT_EQ(Hash("\x56\xdc\xd6", 3, kSeed), 2157698265u);
EXPECT_EQ(Hash("\xd4\x52\x33", 3, kSeed), 1721992661u);
EXPECT_EQ(Hash("\x6a\xb5\xf4", 3, kSeed), 2469105222u);
EXPECT_EQ(Hash("\x67\x53\x81\x1c", 4, kSeed), 118283265u);
EXPECT_EQ(Hash("\x69\xb8\xc0\x88", 4, kSeed), 3416318611u);
EXPECT_EQ(Hash("\x1e\x84\xaf\x2d", 4, kSeed), 3315003572u);
EXPECT_EQ(Hash("\x46\xdc\x54\xbe", 4, kSeed), 447346355u);
EXPECT_EQ(Hash("\xd0\x7a\x6e\xea\x56", 5, kSeed), 4255445370u);
EXPECT_EQ(Hash("\x86\x83\xd5\xa4\xd8", 5, kSeed), 2390603402u);
EXPECT_EQ(Hash("\xb7\x46\xbb\x77\xce", 5, kSeed), 2048907743u);
EXPECT_EQ(Hash("\x6c\xa8\xbc\xe5\x99", 5, kSeed), 2177978500u);
EXPECT_EQ(Hash("\x5c\x5e\xe1\xa0\x73\x81", 6, kSeed), 1036846008u);
EXPECT_EQ(Hash("\x08\x5d\x73\x1c\xe5\x2e", 6, kSeed), 229980482u);
EXPECT_EQ(Hash("\x42\xfb\xf2\x52\xb4\x10", 6, kSeed), 3655585422u);
EXPECT_EQ(Hash("\x73\xe1\xff\x56\x9c\xce", 6, kSeed), 3502708029u);
EXPECT_EQ(Hash("\x5c\xbe\x97\x75\x54\x9a\x52", 7, kSeed), 815120748u);
EXPECT_EQ(Hash("\x16\x82\x39\x49\x88\x2b\x36", 7, kSeed), 3056033698u);
EXPECT_EQ(Hash("\x59\x77\xf0\xa7\x24\xf4\x78", 7, kSeed), 587205227u);
EXPECT_EQ(Hash("\xd3\xa5\x7c\x0e\xc0\x02\x07", 7, kSeed), 2030937252u);
EXPECT_EQ(Hash("\x31\x1b\x98\x75\x96\x22\xd3\x9a", 8, kSeed), 469635402u);
EXPECT_EQ(Hash("\x38\xd6\xf7\x28\x20\xb4\x8a\xe9", 8, kSeed), 3530274698u);
EXPECT_EQ(Hash("\xbb\x18\x5d\xf4\x12\x03\xf7\x99", 8, kSeed), 1974545809u);
EXPECT_EQ(Hash("\x80\xd4\x3b\x3b\xae\x22\xa2\x78", 8, kSeed), 3563570120u);
EXPECT_EQ(Hash("\x1a\xb5\xd0\xfe\xab\xc3\x61\xb2\x99", 9, kSeed),
2706087434u);
EXPECT_EQ(Hash("\x8e\x4a\xc3\x18\x20\x2f\x06\xe6\x3c", 9, kSeed),
1534654151u);
EXPECT_EQ(Hash("\xb6\xc0\xdd\x05\x3f\xc4\x86\x4c\xef", 9, kSeed),
2355554696u);
EXPECT_EQ(Hash("\x9a\x5f\x78\x0d\xaf\x50\xe1\x1f\x55", 9, kSeed),
1400800912u);
EXPECT_EQ(Hash("\x22\x6f\x39\x1f\xf8\xdd\x4f\x52\x17\x94", 10, kSeed),
3420325137u);
EXPECT_EQ(Hash("\x32\x89\x2a\x75\x48\x3a\x4a\x02\x69\xdd", 10, kSeed),
3427803584u);
EXPECT_EQ(Hash("\x06\x92\x5c\xf4\x88\x0e\x7e\x68\x38\x3e", 10, kSeed),
1152407945u);
EXPECT_EQ(Hash("\xbd\x2c\x63\x38\xbf\xe9\x78\xb7\xbf\x15", 10, kSeed),
3382479516u);
}
// The hash algorithm is part of the file format, for example for the Bloom
// filters.
TEST(HashTest, Hash64Misc) {
constexpr uint32_t kSeed = 0; // Same as GetSliceHash64
for (char fill : {'\0', 'a', '1', '\xff'}) {
const size_t max_size = 1000;
const std::string str(max_size, fill);
for (size_t size = 0; size <= max_size; ++size) {
uint64_t here = Hash64(str.data(), size, kSeed);
// Must be same as unseeded Hash64 and GetSliceHash64
EXPECT_EQ(here, Hash64(str.data(), size));
EXPECT_EQ(here, GetSliceHash64(Slice(str.data(), size)));
// Upper and Lower must reconstruct hash
EXPECT_EQ(here, (uint64_t{Upper32of64(here)} << 32) | Lower32of64(here));
EXPECT_EQ(here, (uint64_t{Upper32of64(here)} << 32) + Lower32of64(here));
EXPECT_EQ(here, (uint64_t{Upper32of64(here)} << 32) ^ Lower32of64(here));
// Seed changes hash value (with high probability)
for (uint64_t var_seed = 1; var_seed != 0; var_seed <<= 1) {
EXPECT_NE(here, Hash64(str.data(), size, var_seed));
}
// Size changes hash value (with high probability)
size_t max_smaller_by = std::min(size_t{30}, size);
for (size_t smaller_by = 1; smaller_by <= max_smaller_by; ++smaller_by) {
EXPECT_NE(here, Hash64(str.data(), size - smaller_by, kSeed));
}
}
}
}
// Test that hash values are "non-trivial" for "trivial" inputs
TEST(HashTest, Hash64Trivial) {
// Thorough test too slow for regression testing
constexpr bool thorough = false;
// For various seeds, make sure hash of empty string is not zero.
constexpr uint64_t max_seed = thorough ? 0x1000000 : 0x10000;
for (uint64_t seed = 0; seed < max_seed; ++seed) {
uint64_t here = Hash64("", 0, seed);
EXPECT_NE(Lower32of64(here), 0u);
EXPECT_NE(Upper32of64(here), 0u);
}
// For standard seed, make sure hash of small strings are not zero
constexpr uint32_t kSeed = 0; // Same as GetSliceHash64
char input[4];
constexpr int max_len = thorough ? 3 : 2;
for (int len = 1; len <= max_len; ++len) {
for (uint32_t i = 0; (i >> (len * 8)) == 0; ++i) {
EncodeFixed32(input, i);
uint64_t here = Hash64(input, len, kSeed);
EXPECT_NE(Lower32of64(here), 0u);
EXPECT_NE(Upper32of64(here), 0u);
}
}
}
// Test that the hash values are stable for a set of random strings of
// varying small lengths.
TEST(HashTest, Hash64SmallValueSchema) {
constexpr uint32_t kSeed = 0; // Same as GetSliceHash64
EXPECT_EQ(Hash64("", 0, kSeed), uint64_t{5999572062939766020u});
EXPECT_EQ(Hash64("\x08", 1, kSeed), uint64_t{583283813901344696u});
EXPECT_EQ(Hash64("\x17", 1, kSeed), uint64_t{16175549975585474943u});
EXPECT_EQ(Hash64("\x9a", 1, kSeed), uint64_t{16322991629225003903u});
EXPECT_EQ(Hash64("\x1c", 1, kSeed), uint64_t{13269285487706833447u});
EXPECT_EQ(Hash64("\x4d\x76", 2, kSeed), uint64_t{6859542833406258115u});
EXPECT_EQ(Hash64("\x52\xd5", 2, kSeed), uint64_t{4919611532550636959u});
EXPECT_EQ(Hash64("\x91\xf7", 2, kSeed), uint64_t{14199427467559720719u});
EXPECT_EQ(Hash64("\xd6\x27", 2, kSeed), uint64_t{12292689282614532691u});
EXPECT_EQ(Hash64("\x30\x46\x0b", 3, kSeed), uint64_t{11404699285340020889u});
EXPECT_EQ(Hash64("\x56\xdc\xd6", 3, kSeed), uint64_t{12404347133785524237u});
EXPECT_EQ(Hash64("\xd4\x52\x33", 3, kSeed), uint64_t{15853805298481534034u});
EXPECT_EQ(Hash64("\x6a\xb5\xf4", 3, kSeed), uint64_t{16863488758399383382u});
EXPECT_EQ(Hash64("\x67\x53\x81\x1c", 4, kSeed),
uint64_t{9010661983527562386u});
EXPECT_EQ(Hash64("\x69\xb8\xc0\x88", 4, kSeed),
uint64_t{6611781377647041447u});
EXPECT_EQ(Hash64("\x1e\x84\xaf\x2d", 4, kSeed),
uint64_t{15290969111616346501u});
EXPECT_EQ(Hash64("\x46\xdc\x54\xbe", 4, kSeed),
uint64_t{7063754590279313623u});
EXPECT_EQ(Hash64("\xd0\x7a\x6e\xea\x56", 5, kSeed),
uint64_t{6384167718754869899u});
EXPECT_EQ(Hash64("\x86\x83\xd5\xa4\xd8", 5, kSeed),
uint64_t{16874407254108011067u});
EXPECT_EQ(Hash64("\xb7\x46\xbb\x77\xce", 5, kSeed),
uint64_t{16809880630149135206u});
EXPECT_EQ(Hash64("\x6c\xa8\xbc\xe5\x99", 5, kSeed),
uint64_t{1249038833153141148u});
EXPECT_EQ(Hash64("\x5c\x5e\xe1\xa0\x73\x81", 6, kSeed),
uint64_t{17358142495308219330u});
EXPECT_EQ(Hash64("\x08\x5d\x73\x1c\xe5\x2e", 6, kSeed),
uint64_t{4237646583134806322u});
EXPECT_EQ(Hash64("\x42\xfb\xf2\x52\xb4\x10", 6, kSeed),
uint64_t{4373664924115234051u});
EXPECT_EQ(Hash64("\x73\xe1\xff\x56\x9c\xce", 6, kSeed),
uint64_t{12012981210634596029u});
EXPECT_EQ(Hash64("\x5c\xbe\x97\x75\x54\x9a\x52", 7, kSeed),
uint64_t{5716522398211028826u});
EXPECT_EQ(Hash64("\x16\x82\x39\x49\x88\x2b\x36", 7, kSeed),
uint64_t{15604531309862565013u});
EXPECT_EQ(Hash64("\x59\x77\xf0\xa7\x24\xf4\x78", 7, kSeed),
uint64_t{8601330687345614172u});
EXPECT_EQ(Hash64("\xd3\xa5\x7c\x0e\xc0\x02\x07", 7, kSeed),
uint64_t{8088079329364056942u});
EXPECT_EQ(Hash64("\x31\x1b\x98\x75\x96\x22\xd3\x9a", 8, kSeed),
uint64_t{9844314944338447628u});
EXPECT_EQ(Hash64("\x38\xd6\xf7\x28\x20\xb4\x8a\xe9", 8, kSeed),
uint64_t{10973293517982163143u});
EXPECT_EQ(Hash64("\xbb\x18\x5d\xf4\x12\x03\xf7\x99", 8, kSeed),
uint64_t{9986007080564743219u});
EXPECT_EQ(Hash64("\x80\xd4\x3b\x3b\xae\x22\xa2\x78", 8, kSeed),
uint64_t{1729303145008254458u});
EXPECT_EQ(Hash64("\x1a\xb5\xd0\xfe\xab\xc3\x61\xb2\x99", 9, kSeed),
uint64_t{13253403748084181481u});
EXPECT_EQ(Hash64("\x8e\x4a\xc3\x18\x20\x2f\x06\xe6\x3c", 9, kSeed),
uint64_t{7768754303876232188u});
EXPECT_EQ(Hash64("\xb6\xc0\xdd\x05\x3f\xc4\x86\x4c\xef", 9, kSeed),
uint64_t{12439346786701492u});
EXPECT_EQ(Hash64("\x9a\x5f\x78\x0d\xaf\x50\xe1\x1f\x55", 9, kSeed),
uint64_t{10841838338450144690u});
EXPECT_EQ(Hash64("\x22\x6f\x39\x1f\xf8\xdd\x4f\x52\x17\x94", 10, kSeed),
uint64_t{12883919702069153152u});
EXPECT_EQ(Hash64("\x32\x89\x2a\x75\x48\x3a\x4a\x02\x69\xdd", 10, kSeed),
uint64_t{12692903507676842188u});
EXPECT_EQ(Hash64("\x06\x92\x5c\xf4\x88\x0e\x7e\x68\x38\x3e", 10, kSeed),
uint64_t{6540985900674032620u});
EXPECT_EQ(Hash64("\xbd\x2c\x63\x38\xbf\xe9\x78\xb7\xbf\x15", 10, kSeed),
uint64_t{10551812464348219044u});
}
std::string Hash64TestDescriptor(const char *repeat, size_t limit) {
const char *mod61_encode =
"abcdefghijklmnopqrstuvwxyz123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
std::string input;
while (input.size() < limit) {
input.append(repeat);
}
std::string rv;
for (size_t i = 0; i < limit; ++i) {
uint64_t h = GetSliceHash64(Slice(input.data(), i));
rv.append(1, mod61_encode[static_cast<size_t>(h % 61)]);
}
return rv;
}
// XXPH3 changes its algorithm for various sizes up through 250 bytes, so
// we need to check the stability of larger sizes also.
TEST(HashTest, Hash64LargeValueSchema) {
// Each of these derives a "descriptor" from the hash values for all
// lengths up to 430.
// Note that "c" is common for the zero-length string.
EXPECT_EQ(
Hash64TestDescriptor("foo", 430),
"cRhyWsY67B6klRA1udmOuiYuX7IthyGBKqbeosz2hzVglWCmQx8nEdnpkvPfYX56Up2OWOTV"
"lTzfAoYwvtqKzjD8E9xttR2unelbXbIV67NUe6bOO23BxaSFRcA3njGu5cUWfgwOqNoTsszp"
"uPvKRP6qaUR5VdoBkJUCFIefd7edlNK5mv6JYWaGdwxehg65hTkTmjZoPKxTZo4PLyzbL9U4"
"xt12ITSfeP2MfBHuLI2z2pDlBb44UQKVMx27LEoAHsdLp3WfWfgH3sdRBRCHm33UxCM4QmE2"
"xJ7gqSvNwTeH7v9GlC8zWbGroyD3UVNeShMLx29O7tH1biemLULwAHyIw8zdtLMDpEJ8m2ic"
"l6Lb4fDuuFNAs1GCVUthjK8CV8SWI8Rsz5THSwn5CGhpqUwSZcFknjwWIl5rNCvDxXJqYr");
// Note that "1EeRk" is common for "Rocks"
EXPECT_EQ(
Hash64TestDescriptor("Rocks", 430),
"c1EeRkrzgOYWLA8PuhJrwTePJewoB44WdXYDfhbk3ZxTqqg25WlPExDl7IKIQLJvnA6gJxxn"
"9TCSLkFGfJeXehaSS1GBqWSzfhEH4VXiXIUCuxJXxtKXcSC6FrNIQGTZbYDiUOLD6Y5inzrF"
"9etwQhXUBanw55xAUdNMFQAm2GjJ6UDWp2mISLiMMkLjANWMKLaZMqaFLX37qB4MRO1ooVRv"
"zSvaNRSCLxlggQCasQq8icWjzf3HjBlZtU6pd4rkaUxSzHqmo9oM5MghbU5Rtxg8wEfO7lVN"
"5wdMONYecslQTwjZUpO1K3LDf3K3XK6sUXM6ShQQ3RHmMn2acB4YtTZ3QQcHYJSOHn2DuWpa"
"Q8RqzX5lab92YmOLaCdOHq1BPsM7SIBzMdLgePNsJ1vvMALxAaoDUHPxoFLO2wx18IXnyX");
EXPECT_EQ(
Hash64TestDescriptor("RocksDB", 430),
"c1EeRkukbkb28wLTahwD2sfUhZzaBEnF8SVrxnPVB6A7b8CaAl3UKsDZISF92GSq2wDCukOq"
"Jgrsp7A3KZhDiLW8dFXp8UPqPxMCRlMdZeVeJ2dJxrmA6cyt99zkQFj7ELbut6jAeVqARFnw"
"fnWVXOsaLrq7bDCbMcns2DKvTaaqTCLMYxI7nhtLpFN1jR755FRQFcOzrrDbh7QhypjdvlYw"
"cdAMSZgp9JMHxbM23wPSuH6BOFgxejz35PScZfhDPvTOxIy1jc3MZsWrMC3P324zNolO7JdW"
"CX2I5UDKjjaEJfxbgVgJIXxtQGlmj2xkO5sPpjULQV4X2HlY7FQleJ4QRaJIB4buhCA4vUTF"
"eMFlxCIYUpTCsal2qsmnGOWa8WCcefrohMjDj1fjzSvSaQwlpyR1GZHF2uPOoQagiCpHpm");
}
TEST(HashTest, Hash128Misc) {
constexpr uint32_t kSeed = 0; // Same as GetSliceHash128
for (char fill : {'\0', 'a', '1', '\xff', 'e'}) {
const size_t max_size = 1000;
std::string str(max_size, fill);
if (fill == 'e') {
// Use different characters to check endianness handling
for (size_t i = 0; i < str.size(); ++i) {
str[i] += static_cast<char>(i);
}
}
for (size_t size = 0; size <= max_size; ++size) {
Unsigned128 here = Hash128(str.data(), size, kSeed);
// Must be same as unseeded Hash128 and GetSliceHash128
EXPECT_EQ(here, Hash128(str.data(), size));
EXPECT_EQ(here, GetSliceHash128(Slice(str.data(), size)));
{
uint64_t hi, lo;
Hash2x64(str.data(), size, &hi, &lo);
EXPECT_EQ(Lower64of128(here), lo);
EXPECT_EQ(Upper64of128(here), hi);
}
if (size == 16) {
const uint64_t in_hi = DecodeFixed64(str.data() + 8);
const uint64_t in_lo = DecodeFixed64(str.data());
uint64_t hi, lo;
BijectiveHash2x64(in_hi, in_lo, &hi, &lo);
EXPECT_EQ(Lower64of128(here), lo);
EXPECT_EQ(Upper64of128(here), hi);
uint64_t un_hi, un_lo;
BijectiveUnhash2x64(hi, lo, &un_hi, &un_lo);
EXPECT_EQ(in_lo, un_lo);
EXPECT_EQ(in_hi, un_hi);
}
// Upper and Lower must reconstruct hash
EXPECT_EQ(here,
(Unsigned128{Upper64of128(here)} << 64) | Lower64of128(here));
EXPECT_EQ(here,
(Unsigned128{Upper64of128(here)} << 64) ^ Lower64of128(here));
// Seed changes hash value (with high probability)
for (uint64_t var_seed = 1; var_seed != 0; var_seed <<= 1) {
Unsigned128 seeded = Hash128(str.data(), size, var_seed);
EXPECT_NE(here, seeded);
// Must match seeded Hash2x64
{
uint64_t hi, lo;
Hash2x64(str.data(), size, var_seed, &hi, &lo);
EXPECT_EQ(Lower64of128(seeded), lo);
EXPECT_EQ(Upper64of128(seeded), hi);
}
if (size == 16) {
const uint64_t in_hi = DecodeFixed64(str.data() + 8);
const uint64_t in_lo = DecodeFixed64(str.data());
uint64_t hi, lo;
BijectiveHash2x64(in_hi, in_lo, var_seed, &hi, &lo);
EXPECT_EQ(Lower64of128(seeded), lo);
EXPECT_EQ(Upper64of128(seeded), hi);
uint64_t un_hi, un_lo;
BijectiveUnhash2x64(hi, lo, var_seed, &un_hi, &un_lo);
EXPECT_EQ(in_lo, un_lo);
EXPECT_EQ(in_hi, un_hi);
}
}
// Size changes hash value (with high probability)
size_t max_smaller_by = std::min(size_t{30}, size);
for (size_t smaller_by = 1; smaller_by <= max_smaller_by; ++smaller_by) {
EXPECT_NE(here, Hash128(str.data(), size - smaller_by, kSeed));
}
}
}
}
// Test that hash values are "non-trivial" for "trivial" inputs
TEST(HashTest, Hash128Trivial) {
// Thorough test too slow for regression testing
constexpr bool thorough = false;
// For various seeds, make sure hash of empty string is not zero.
constexpr uint64_t max_seed = thorough ? 0x1000000 : 0x10000;
for (uint64_t seed = 0; seed < max_seed; ++seed) {
Unsigned128 here = Hash128("", 0, seed);
EXPECT_NE(Lower64of128(here), 0u);
EXPECT_NE(Upper64of128(here), 0u);
}
// For standard seed, make sure hash of small strings are not zero
constexpr uint32_t kSeed = 0; // Same as GetSliceHash128
char input[4];
constexpr int max_len = thorough ? 3 : 2;
for (int len = 1; len <= max_len; ++len) {
for (uint32_t i = 0; (i >> (len * 8)) == 0; ++i) {
EncodeFixed32(input, i);
Unsigned128 here = Hash128(input, len, kSeed);
EXPECT_NE(Lower64of128(here), 0u);
EXPECT_NE(Upper64of128(here), 0u);
}
}
}
std::string Hash128TestDescriptor(const char *repeat, size_t limit) {
const char *mod61_encode =
"abcdefghijklmnopqrstuvwxyz123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
std::string input;
while (input.size() < limit) {
input.append(repeat);
}
std::string rv;
for (size_t i = 0; i < limit; ++i) {
auto h = GetSliceHash128(Slice(input.data(), i));
uint64_t h2 = Upper64of128(h) + Lower64of128(h);
rv.append(1, mod61_encode[static_cast<size_t>(h2 % 61)]);
}
return rv;
}
// XXH3 changes its algorithm for various sizes up through 250 bytes, so
// we need to check the stability of larger sizes also.
TEST(HashTest, Hash128ValueSchema) {
// Each of these derives a "descriptor" from the hash values for all
// lengths up to 430.
// Note that "b" is common for the zero-length string.
EXPECT_EQ(
Hash128TestDescriptor("foo", 430),
"bUMA3As8n9I4vNGhThXlEevxZlyMcbb6TYAlIKJ2f5ponsv99q962rYclQ7u3gfnRdCDQ5JI"
"2LrGUaCycbXrvLFe4SjgRb9RQwCfrnmNQ7VSEwSKMnkGCK3bDbXSrnIh5qLXdtvIZklbJpGH"
"Dqr93BlqF9ubTnOSYkSdx89XvQqflMIW8bjfQp9BPjQejWOeEQspnN1D3sfgVdFhpaQdHYA5"
"pI2XcPlCMFPxvrFuRr7joaDvjNe9IUZaunLPMewuXmC3EL95h52Ju3D7y9RNKhgYxMTrA84B"
"yJrMvyjdm3vlBxet4EN7v2GEyjbGuaZW9UL6lrX6PghJDg7ACfLGdxNbH3qXM4zaiG2RKnL5"
"S3WXKR78RBB5fRFQ8KDIEQjHFvSNsc3GrAEi6W8P2lv8JMTzjBODO2uN4wadVQFT9wpGfV");
// Note that "35D2v" is common for "Rocks"
EXPECT_EQ(
Hash128TestDescriptor("Rocks", 430),
"b35D2vzvklFVDqJmyLRXyApwGGO3EAT3swhe8XJAN3mY2UVPglzdmydxcba6JI2tSvwO6zSu"
"ANpjSM7tc9G5iMhsa7R8GfyCXRO1TnLg7HvdWNdgGGBirxZR68BgT7TQsYJt6zyEyISeXI1n"
"MXA48Xo7dWfJeYN6Z4KWlqZY7TgFXGbks9AX4ehZNSGtIhdO5i58qlgVX1bEejeOVaCcjC79"
"67DrMfOKds7rUQzjBa77sMPcoPW1vu6ljGJPZH3XkRyDMZ1twxXKkNxN3tE8nR7JHwyqBAxE"
"fTcjbOWrLZ1irWxRSombD8sGDEmclgF11IxqEhe3Rt7gyofO3nExGckKkS9KfRqsCHbiUyva"
"JGkJwUHRXaZnh58b4i1Ei9aQKZjXlvIVDixoZrjcNaH5XJIJlRZce9Z9t82wYapTpckYSg");
EXPECT_EQ(
Hash128TestDescriptor("RocksDB", 430),
"b35D2vFUst3XDZCRlSrhmYYakmqImV97LbBsV6EZlOEQpUPH1d1sD3xMKAPlA5UErHehg5O7"
"n966fZqhAf3hRc24kGCLfNAWjyUa7vSNOx3IcPoTyVRFZeFlcCtfl7t1QJumHOCpS33EBmBF"
"hvK13QjBbDWYWeHQhJhgV9Mqbx17TIcvUkEnYZxb8IzWNmjVsJG44Z7v52DjGj1ZzS62S2Vv"
"qWcDO7apvH5VHg68E9Wl6nXP21vlmUqEH9GeWRehfWVvY7mUpsAg5drHHQyDSdiMceiUuUxJ"
"XJqHFcDdzbbPk7xDvbLgWCKvH8k3MpQNWOmbSSRDdAP6nGlDjoTToYkcqVREHJzztSWAAq5h"
"GHSUNJ6OxsMHhf8EhXfHtKyUzRmPtjYyeckQcGmrQfFFLidc6cjMDKCdBG6c6HVBrS7H2R");
}
TEST(FastRange32Test, Values) {
using ROCKSDB_NAMESPACE::FastRange32;
// Zero range
EXPECT_EQ(FastRange32(0, 0), 0U);
EXPECT_EQ(FastRange32(123, 0), 0U);
EXPECT_EQ(FastRange32(0xffffffff, 0), 0U);
// One range
EXPECT_EQ(FastRange32(0, 1), 0U);
EXPECT_EQ(FastRange32(123, 1), 0U);
EXPECT_EQ(FastRange32(0xffffffff, 1), 0U);
// Two range
EXPECT_EQ(FastRange32(0, 2), 0U);
EXPECT_EQ(FastRange32(123, 2), 0U);
EXPECT_EQ(FastRange32(0x7fffffff, 2), 0U);
EXPECT_EQ(FastRange32(0x80000000, 2), 1U);
EXPECT_EQ(FastRange32(0xffffffff, 2), 1U);
// Seven range
EXPECT_EQ(FastRange32(0, 7), 0U);
EXPECT_EQ(FastRange32(123, 7), 0U);
EXPECT_EQ(FastRange32(613566756, 7), 0U);
EXPECT_EQ(FastRange32(613566757, 7), 1U);
EXPECT_EQ(FastRange32(1227133513, 7), 1U);
EXPECT_EQ(FastRange32(1227133514, 7), 2U);
// etc.
EXPECT_EQ(FastRange32(0xffffffff, 7), 6U);
// Big
EXPECT_EQ(FastRange32(1, 0x80000000), 0U);
EXPECT_EQ(FastRange32(2, 0x80000000), 1U);
EXPECT_EQ(FastRange32(4, 0x7fffffff), 1U);
EXPECT_EQ(FastRange32(4, 0x80000000), 2U);
EXPECT_EQ(FastRange32(0xffffffff, 0x7fffffff), 0x7ffffffeU);
EXPECT_EQ(FastRange32(0xffffffff, 0x80000000), 0x7fffffffU);
}
TEST(FastRange64Test, Values) {
using ROCKSDB_NAMESPACE::FastRange64;
// Zero range
EXPECT_EQ(FastRange64(0, 0), 0U);
EXPECT_EQ(FastRange64(123, 0), 0U);
EXPECT_EQ(FastRange64(0xffffFFFF, 0), 0U);
EXPECT_EQ(FastRange64(0xffffFFFFffffFFFF, 0), 0U);
// One range
EXPECT_EQ(FastRange64(0, 1), 0U);
EXPECT_EQ(FastRange64(123, 1), 0U);
EXPECT_EQ(FastRange64(0xffffFFFF, 1), 0U);
EXPECT_EQ(FastRange64(0xffffFFFFffffFFFF, 1), 0U);
// Two range
EXPECT_EQ(FastRange64(0, 2), 0U);
EXPECT_EQ(FastRange64(123, 2), 0U);
EXPECT_EQ(FastRange64(0xffffFFFF, 2), 0U);
EXPECT_EQ(FastRange64(0x7fffFFFFffffFFFF, 2), 0U);
EXPECT_EQ(FastRange64(0x8000000000000000, 2), 1U);
EXPECT_EQ(FastRange64(0xffffFFFFffffFFFF, 2), 1U);
// Seven range
EXPECT_EQ(FastRange64(0, 7), 0U);
EXPECT_EQ(FastRange64(123, 7), 0U);
EXPECT_EQ(FastRange64(0xffffFFFF, 7), 0U);
EXPECT_EQ(FastRange64(2635249153387078802, 7), 0U);
EXPECT_EQ(FastRange64(2635249153387078803, 7), 1U);
EXPECT_EQ(FastRange64(5270498306774157604, 7), 1U);
EXPECT_EQ(FastRange64(5270498306774157605, 7), 2U);
EXPECT_EQ(FastRange64(0x7fffFFFFffffFFFF, 7), 3U);
EXPECT_EQ(FastRange64(0x8000000000000000, 7), 3U);
EXPECT_EQ(FastRange64(0xffffFFFFffffFFFF, 7), 6U);
// Big but 32-bit range
EXPECT_EQ(FastRange64(0x100000000, 0x80000000), 0U);
EXPECT_EQ(FastRange64(0x200000000, 0x80000000), 1U);
EXPECT_EQ(FastRange64(0x400000000, 0x7fffFFFF), 1U);
EXPECT_EQ(FastRange64(0x400000000, 0x80000000), 2U);
EXPECT_EQ(FastRange64(0xffffFFFFffffFFFF, 0x7fffFFFF), 0x7fffFFFEU);
EXPECT_EQ(FastRange64(0xffffFFFFffffFFFF, 0x80000000), 0x7fffFFFFU);
// Big, > 32-bit range
#if SIZE_MAX == UINT64_MAX
EXPECT_EQ(FastRange64(0x7fffFFFFffffFFFF, 0x4200000002), 0x2100000000U);
EXPECT_EQ(FastRange64(0x8000000000000000, 0x4200000002), 0x2100000001U);
EXPECT_EQ(FastRange64(0x0000000000000000, 420000000002), 0U);
EXPECT_EQ(FastRange64(0x7fffFFFFffffFFFF, 420000000002), 210000000000U);
EXPECT_EQ(FastRange64(0x8000000000000000, 420000000002), 210000000001U);
EXPECT_EQ(FastRange64(0xffffFFFFffffFFFF, 420000000002), 420000000001U);
EXPECT_EQ(FastRange64(0xffffFFFFffffFFFF, 0xffffFFFFffffFFFF),
0xffffFFFFffffFFFEU);
#endif
}
TEST(FastRangeGenericTest, Values) {
using ROCKSDB_NAMESPACE::FastRangeGeneric;
// Generic (including big and small)
// Note that FastRangeGeneric is also tested indirectly above via
// FastRange32 and FastRange64.
EXPECT_EQ(
FastRangeGeneric(uint64_t{0x8000000000000000}, uint64_t{420000000002}),
uint64_t{210000000001});
EXPECT_EQ(FastRangeGeneric(uint64_t{0x8000000000000000}, uint16_t{12468}),
uint16_t{6234});
EXPECT_EQ(FastRangeGeneric(uint32_t{0x80000000}, uint16_t{12468}),
uint16_t{6234});
// Not recommended for typical use because for example this could fail on
// some platforms and pass on others:
//EXPECT_EQ(FastRangeGeneric(static_cast<unsigned long>(0x80000000),
// uint16_t{12468}),
// uint16_t{6234});
}
// for inspection of disassembly
uint32_t FastRange32(uint32_t hash, uint32_t range) {
return ROCKSDB_NAMESPACE::FastRange32(hash, range);
}
// for inspection of disassembly
size_t FastRange64(uint64_t hash, size_t range) {
return ROCKSDB_NAMESPACE::FastRange64(hash, range);
}
// Tests for math.h / math128.h (not worth a separate test binary)
using ROCKSDB_NAMESPACE::BitParity;
using ROCKSDB_NAMESPACE::BitsSetToOne;
using ROCKSDB_NAMESPACE::CountTrailingZeroBits;
using ROCKSDB_NAMESPACE::DecodeFixed128;
using ROCKSDB_NAMESPACE::DecodeFixedGeneric;
using ROCKSDB_NAMESPACE::EncodeFixed128;
using ROCKSDB_NAMESPACE::EncodeFixedGeneric;
using ROCKSDB_NAMESPACE::FloorLog2;
using ROCKSDB_NAMESPACE::Lower64of128;
using ROCKSDB_NAMESPACE::Multiply64to128;
using ROCKSDB_NAMESPACE::Unsigned128;
using ROCKSDB_NAMESPACE::Upper64of128;
template <typename T>
static void test_BitOps() {
// This complex code is to generalize to 128-bit values. Otherwise
// we could just use = static_cast<T>(0x5555555555555555ULL);
T everyOtherBit = 0;
for (unsigned i = 0; i < sizeof(T); ++i) {
everyOtherBit = (everyOtherBit << 8) | T{0x55};
}
// This one built using bit operations, as our 128-bit layer
// might not implement arithmetic such as subtraction.
T vm1 = 0; // "v minus one"
for (int i = 0; i < int{8 * sizeof(T)}; ++i) {
T v = T{1} << i;
// If we could directly use arithmetic:
// T vm1 = static_cast<T>(v - 1);
// FloorLog2
if (v > 0) {
EXPECT_EQ(FloorLog2(v), i);
}
if (vm1 > 0) {
EXPECT_EQ(FloorLog2(vm1), i - 1);
EXPECT_EQ(FloorLog2(everyOtherBit & vm1), (i - 1) & ~1);
}
// CountTrailingZeroBits
if (v != 0) {
EXPECT_EQ(CountTrailingZeroBits(v), i);
}
if (vm1 != 0) {
EXPECT_EQ(CountTrailingZeroBits(vm1), 0);
}
if (i < int{8 * sizeof(T)} - 1) {
EXPECT_EQ(CountTrailingZeroBits(~vm1 & everyOtherBit), (i + 1) & ~1);
}
// BitsSetToOne
EXPECT_EQ(BitsSetToOne(v), 1);
EXPECT_EQ(BitsSetToOne(vm1), i);
EXPECT_EQ(BitsSetToOne(vm1 & everyOtherBit), (i + 1) / 2);
// BitParity
EXPECT_EQ(BitParity(v), 1);
EXPECT_EQ(BitParity(vm1), i & 1);
EXPECT_EQ(BitParity(vm1 & everyOtherBit), ((i + 1) / 2) & 1);
vm1 = (vm1 << 1) | 1;
}
}
TEST(MathTest, BitOps) {
test_BitOps<uint32_t>();
test_BitOps<uint64_t>();
test_BitOps<uint16_t>();
test_BitOps<uint8_t>();
test_BitOps<unsigned char>();
test_BitOps<unsigned short>();
test_BitOps<unsigned int>();
test_BitOps<unsigned long>();
test_BitOps<unsigned long long>();
test_BitOps<char>();
test_BitOps<size_t>();
test_BitOps<int32_t>();
test_BitOps<int64_t>();
test_BitOps<int16_t>();
test_BitOps<int8_t>();
test_BitOps<signed char>();
test_BitOps<short>();
test_BitOps<int>();
test_BitOps<long>();
test_BitOps<long long>();
test_BitOps<ptrdiff_t>();
}
TEST(MathTest, BitOps128) { test_BitOps<Unsigned128>(); }
TEST(MathTest, Math128) {
const Unsigned128 sixteenHexOnes = 0x1111111111111111U;
const Unsigned128 thirtyHexOnes = (sixteenHexOnes << 56) | sixteenHexOnes;
const Unsigned128 sixteenHexTwos = 0x2222222222222222U;
const Unsigned128 thirtyHexTwos = (sixteenHexTwos << 56) | sixteenHexTwos;
// v will slide from all hex ones to all hex twos
Unsigned128 v = thirtyHexOnes;
for (int i = 0; i <= 30; ++i) {
// Test bitwise operations
EXPECT_EQ(BitsSetToOne(v), 30);
EXPECT_EQ(BitsSetToOne(~v), 128 - 30);
EXPECT_EQ(BitsSetToOne(v & thirtyHexOnes), 30 - i);
EXPECT_EQ(BitsSetToOne(v | thirtyHexOnes), 30 + i);
EXPECT_EQ(BitsSetToOne(v ^ thirtyHexOnes), 2 * i);
EXPECT_EQ(BitsSetToOne(v & thirtyHexTwos), i);
EXPECT_EQ(BitsSetToOne(v | thirtyHexTwos), 60 - i);
EXPECT_EQ(BitsSetToOne(v ^ thirtyHexTwos), 60 - 2 * i);
// Test comparisons
EXPECT_EQ(v == thirtyHexOnes, i == 0);
EXPECT_EQ(v == thirtyHexTwos, i == 30);
EXPECT_EQ(v > thirtyHexOnes, i > 0);
EXPECT_EQ(v > thirtyHexTwos, false);
EXPECT_EQ(v >= thirtyHexOnes, true);
EXPECT_EQ(v >= thirtyHexTwos, i == 30);
EXPECT_EQ(v < thirtyHexOnes, false);
EXPECT_EQ(v < thirtyHexTwos, i < 30);
EXPECT_EQ(v <= thirtyHexOnes, i == 0);
EXPECT_EQ(v <= thirtyHexTwos, true);
// Update v, clearing upper-most byte
v = ((v << 12) >> 8) | 0x2;
}
for (int i = 0; i < 128; ++i) {
// Test shifts
Unsigned128 sl = thirtyHexOnes << i;
Unsigned128 sr = thirtyHexOnes >> i;
EXPECT_EQ(BitsSetToOne(sl), std::min(30, 32 - i / 4));
EXPECT_EQ(BitsSetToOne(sr), std::max(0, 30 - (i + 3) / 4));
EXPECT_EQ(BitsSetToOne(sl & sr), i % 2 ? 0 : std::max(0, 30 - i / 2));
}
// Test 64x64->128 multiply
Unsigned128 product =
Multiply64to128(0x1111111111111111U, 0x2222222222222222U);
EXPECT_EQ(Lower64of128(product), 2295594818061633090U);
EXPECT_EQ(Upper64of128(product), 163971058432973792U);
}
TEST(MathTest, Coding128) {
const char *in = "_1234567890123456";
// Note: in + 1 is likely unaligned
Unsigned128 decoded = DecodeFixed128(in + 1);
EXPECT_EQ(Lower64of128(decoded), 0x3837363534333231U);
EXPECT_EQ(Upper64of128(decoded), 0x3635343332313039U);
char out[18];
out[0] = '_';
EncodeFixed128(out + 1, decoded);
out[17] = '\0';
EXPECT_EQ(std::string(in), std::string(out));
}
TEST(MathTest, CodingGeneric) {
const char *in = "_1234567890123456";
// Decode
// Note: in + 1 is likely unaligned
Unsigned128 decoded128 = DecodeFixedGeneric<Unsigned128>(in + 1);
EXPECT_EQ(Lower64of128(decoded128), 0x3837363534333231U);
EXPECT_EQ(Upper64of128(decoded128), 0x3635343332313039U);
uint64_t decoded64 = DecodeFixedGeneric<uint64_t>(in + 1);
EXPECT_EQ(decoded64, 0x3837363534333231U);
uint32_t decoded32 = DecodeFixedGeneric<uint32_t>(in + 1);
EXPECT_EQ(decoded32, 0x34333231U);
uint16_t decoded16 = DecodeFixedGeneric<uint16_t>(in + 1);
EXPECT_EQ(decoded16, 0x3231U);
// Encode
char out[18];
out[0] = '_';
memset(out + 1, '\0', 17);
EncodeFixedGeneric(out + 1, decoded128);
EXPECT_EQ(std::string(in), std::string(out));
memset(out + 1, '\0', 9);
EncodeFixedGeneric(out + 1, decoded64);
EXPECT_EQ(std::string("_12345678"), std::string(out));
memset(out + 1, '\0', 5);
EncodeFixedGeneric(out + 1, decoded32);
EXPECT_EQ(std::string("_1234"), std::string(out));
memset(out + 1, '\0', 3);
EncodeFixedGeneric(out + 1, decoded16);
EXPECT_EQ(std::string("_12"), std::string(out));
}
int main(int argc, char** argv) {
fprintf(stderr, "NPHash64 id: %x\n",
static_cast<int>(ROCKSDB_NAMESPACE::GetSliceNPHash64("RocksDB")));
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
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