You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@quickstep.apache.org by na...@apache.org on 2016/07/11 23:34:32 UTC
[2/3] incubator-quickstep git commit: Use multiplicative hash instead
of hash_ap
Use multiplicative hash instead of hash_ap
Project: http://git-wip-us.apache.org/repos/asf/incubator-quickstep/repo
Commit: http://git-wip-us.apache.org/repos/asf/incubator-quickstep/commit/499b6613
Tree: http://git-wip-us.apache.org/repos/asf/incubator-quickstep/tree/499b6613
Diff: http://git-wip-us.apache.org/repos/asf/incubator-quickstep/diff/499b6613
Branch: refs/heads/expt_bloom_filter_hash_fn
Commit: 499b6613db75fdac1e96a622bc365549722eee47
Parents: 3e52dbd
Author: Navneet Potti <na...@gmail.com>
Authored: Mon Jul 11 12:45:26 2016 -0500
Committer: Navneet Potti <na...@gmail.com>
Committed: Mon Jul 11 12:45:26 2016 -0500
----------------------------------------------------------------------
utility/BloomFilter.hpp | 104 ++++++++-----------------------------------
1 file changed, 18 insertions(+), 86 deletions(-)
----------------------------------------------------------------------
http://git-wip-us.apache.org/repos/asf/incubator-quickstep/blob/499b6613/utility/BloomFilter.hpp
----------------------------------------------------------------------
diff --git a/utility/BloomFilter.hpp b/utility/BloomFilter.hpp
index b93df84..4125292 100644
--- a/utility/BloomFilter.hpp
+++ b/utility/BloomFilter.hpp
@@ -71,7 +71,6 @@ class BloomFilter {
bit_array_(new std::uint8_t[array_size_in_bytes_]),
is_bit_array_owner_(true) {
reset();
- generate_unique_hash_fn();
}
/**
@@ -100,7 +99,6 @@ class BloomFilter {
if (!is_initialized) {
reset();
}
- generate_unique_hash_fn();
}
/**
@@ -119,7 +117,6 @@ class BloomFilter {
bit_array_(new std::uint8_t[array_size_in_bytes_]),
is_bit_array_owner_(true) {
reset();
- generate_unique_hash_fn();
}
/**
@@ -198,7 +195,7 @@ class BloomFilter {
// Determine all the bit positions that are required to be set.
for (std::size_t i = 0; i < hash_fn_count_; ++i) {
- compute_indices(hash_ap(key_begin, length, hash_fn_[i]), &bit_index, &bit);
+ compute_indices(hash_multiplicative(key_begin, length, hash_fn_[i]), &bit_index, &bit);
modified_bit_positions.push_back(std::make_pair(bit_index, bit));
}
@@ -243,7 +240,7 @@ class BloomFilter {
std::size_t bit = 0;
for (std::size_t i = 0; i < hash_fn_count_; ++i) {
- compute_indices(hash_ap(key_begin, length, hash_fn_[i]), &bit_index, &bit);
+ compute_indices(hash_multiplicative(key_begin, length, hash_fn_[i]), &bit_index, &bit);
(bit_array_.get())[bit_index / kNumBitsPerByte] |= (1 << bit);
}
@@ -265,7 +262,7 @@ class BloomFilter {
std::size_t bit_index = 0;
std::size_t bit = 0;
for (std::size_t i = 0; i < hash_fn_count_; ++i) {
- compute_indices(hash_ap(key_begin, length, hash_fn_[i]), &bit_index, &bit);
+ compute_indices(hash_multiplicative(key_begin, length, hash_fn_[i]), &bit_index, &bit);
if (((bit_array_.get())[bit_index / kNumBitsPerByte] & (1 << bit)) != (1 << bit)) {
return false;
}
@@ -301,88 +298,23 @@ class BloomFilter {
*bit = *bit_index % kNumBitsPerByte;
}
- void generate_unique_hash_fn() {
- hash_fn_.reserve(hash_fn_count_);
- const std::uint32_t predef_hash_fn_count = 128;
- static const std::uint32_t predef_hash_fn[predef_hash_fn_count] = {
- 0xAAAAAAAA, 0x55555555, 0x33333333, 0xCCCCCCCC,
- 0x66666666, 0x99999999, 0xB5B5B5B5, 0x4B4B4B4B,
- 0xAA55AA55, 0x55335533, 0x33CC33CC, 0xCC66CC66,
- 0x66996699, 0x99B599B5, 0xB54BB54B, 0x4BAA4BAA,
- 0xAA33AA33, 0x55CC55CC, 0x33663366, 0xCC99CC99,
- 0x66B566B5, 0x994B994B, 0xB5AAB5AA, 0xAAAAAA33,
- 0x555555CC, 0x33333366, 0xCCCCCC99, 0x666666B5,
- 0x9999994B, 0xB5B5B5AA, 0xFFFFFFFF, 0xFFFF0000,
- 0xB823D5EB, 0xC1191CDF, 0xF623AEB3, 0xDB58499F,
- 0xC8D42E70, 0xB173F616, 0xA91A5967, 0xDA427D63,
- 0xB1E8A2EA, 0xF6C0D155, 0x4909FEA3, 0xA68CC6A7,
- 0xC395E782, 0xA26057EB, 0x0CD5DA28, 0x467C5492,
- 0xF15E6982, 0x61C6FAD3, 0x9615E352, 0x6E9E355A,
- 0x689B563E, 0x0C9831A8, 0x6753C18B, 0xA622689B,
- 0x8CA63C47, 0x42CC2884, 0x8E89919B, 0x6EDBD7D3,
- 0x15B6796C, 0x1D6FDFE4, 0x63FF9092, 0xE7401432,
- 0xEFFE9412, 0xAEAEDF79, 0x9F245A31, 0x83C136FC,
- 0xC3DA4A8C, 0xA5112C8C, 0x5271F491, 0x9A948DAB,
- 0xCEE59A8D, 0xB5F525AB, 0x59D13217, 0x24E7C331,
- 0x697C2103, 0x84B0A460, 0x86156DA9, 0xAEF2AC68,
- 0x23243DA5, 0x3F649643, 0x5FA495A8, 0x67710DF8,
- 0x9A6C499E, 0xDCFB0227, 0x46A43433, 0x1832B07A,
- 0xC46AFF3C, 0xB9C8FFF0, 0xC9500467, 0x34431BDF,
- 0xB652432B, 0xE367F12B, 0x427F4C1B, 0x224C006E,
- 0x2E7E5A89, 0x96F99AA5, 0x0BEB452A, 0x2FD87C39,
- 0x74B2E1FB, 0x222EFD24, 0xF357F60C, 0x440FCB1E,
- 0x8BBE030F, 0x6704DC29, 0x1144D12F, 0x948B1355,
- 0x6D8FD7E9, 0x1C11A014, 0xADD1592F, 0xFB3C712E,
- 0xFC77642F, 0xF9C4CE8C, 0x31312FB9, 0x08B0DD79,
- 0x318FA6E7, 0xC040D23D, 0xC0589AA7, 0x0CA5C075,
- 0xF874B172, 0x0CF914D5, 0x784D3280, 0x4E8CFEBC,
- 0xC569F575, 0xCDB2A091, 0x2CC016B4, 0x5C5F4421
- };
- if (hash_fn_count_ <= predef_hash_fn_count) {
- std::copy(predef_hash_fn, predef_hash_fn + hash_fn_count_, hash_fn_.begin());
- for (std::uint32_t i = 0; i < hash_fn_.size(); ++i) {
- hash_fn_[i] = hash_fn_[i] * hash_fn_[(i + 3) % hash_fn_count_] + static_cast<std::uint32_t>(random_seed_);
+ inline std::uint32_t hash_multiplicative(
+ const std::uint8_t *begin,
+ std::size_t remaining_length,
+ const std::size_t multiplier) const {
+ std::uint32_t hash = 0;
+ std::size_t bytes_hashed = 0;
+ if (remaining_length >= 4) {
+ while (bytes_hashed < remaining_length) {
+ auto val = *reinterpret_cast<const std::uint32_t *>(begin + bytes_hashed);
+ hash = multiplier * hash + val;
+ bytes_hashed += 4;
}
- } else {
- LOG(FATAL) << "Requested number of hash functions is too large.";
- }
- }
-
- inline std::uint32_t hash_ap(const std::uint8_t *begin, std::size_t remaining_length, std::uint32_t hash) const {
- const std::uint8_t *itr = begin;
- std::uint32_t loop = 0;
- while (remaining_length >= 8) {
- const std::uint32_t &i1 = *(reinterpret_cast<const std::uint32_t*>(itr)); itr += sizeof(std::uint32_t);
- const std::uint32_t &i2 = *(reinterpret_cast<const std::uint32_t*>(itr)); itr += sizeof(std::uint32_t);
- hash ^= (hash << 7) ^ i1 * (hash >> 3) ^ (~((hash << 11) + (i2 ^ (hash >> 5))));
- remaining_length -= 8;
}
- if (remaining_length) {
- if (remaining_length >= 4) {
- const std::uint32_t &i = *(reinterpret_cast<const std::uint32_t*>(itr));
- if (loop & 0x01) {
- hash ^= (hash << 7) ^ i * (hash >> 3);
- } else {
- hash ^= (~((hash << 11) + (i ^ (hash >> 5))));
- }
- ++loop;
- remaining_length -= 4;
- itr += sizeof(std::uint32_t);
- }
- if (remaining_length >= 2) {
- const std::uint16_t &i = *(reinterpret_cast<const std::uint16_t*>(itr));
- if (loop & 0x01) {
- hash ^= (hash << 7) ^ i * (hash >> 3);
- } else {
- hash ^= (~((hash << 11) + (i ^ (hash >> 5))));
- }
- ++loop;
- remaining_length -= 2;
- itr += sizeof(std::uint16_t);
- }
- if (remaining_length) {
- hash += ((*itr) ^ (hash * 0xA5A5A5A5)) + loop;
- }
+ while (bytes_hashed < remaining_length) {
+ std::uint8_t val = *(begin + bytes_hashed);
+ hash = multiplier * hash + val;
+ bytes_hashed++;
}
return hash;
}