erigon-pulse/recsplit/index.go
ledgerwatch df49481ddc
[erigon 2.2] Make keys always uncompressed, values compressed only for code (#492)
* Reduce allocations in domain and aggregator

* Make keys always uncompressed, values compressed only for code

* Functions to remake index

* Fix index recreation

* Test for reindex, fix

* Use uncompress vals in history

Co-authored-by: Alexey Sharp <alexeysharp@Alexeys-iMac.local>
2022-06-17 12:39:49 +01:00

306 lines
9.2 KiB
Go

/*
Copyright 2022 Erigon contributors
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package recsplit
import (
"bufio"
"encoding/binary"
"fmt"
"math"
"math/bits"
"os"
"unsafe"
"github.com/ledgerwatch/erigon-lib/mmap"
"github.com/ledgerwatch/erigon-lib/recsplit/eliasfano16"
"github.com/ledgerwatch/erigon-lib/recsplit/eliasfano32"
)
// Index implements index lookup from the file created by the RecSplit
type Index struct {
indexFile string
f *os.File
mmapHandle1 []byte // mmap handle for unix (this is used to close mmap)
mmapHandle2 *[mmap.MaxMapSize]byte // mmap handle for windows (this is used to close mmap)
data []byte // slice of correct size for the index to work with
keyCount uint64
bytesPerRec int
recMask uint64
grData []uint64
ef eliasfano16.DoubleEliasFano
enums bool
offsetEf *eliasfano32.EliasFano
baseDataID uint64
bucketCount uint64 // Number of buckets
bucketSize int
leafSize uint16 // Leaf size for recursive split algorithms
primaryAggrBound uint16 // The lower bound for primary key aggregation (computed from leafSize)
secondaryAggrBound uint16 // The lower bound for secondary key aggregation (computed from leadSize)
salt uint32
startSeed []uint64
golombRice []uint32
size int64
}
func MustOpen(indexFile string) *Index {
idx, err := OpenIndex(indexFile)
if err != nil {
panic(err)
}
return idx
}
func OpenIndex(indexFile string) (*Index, error) {
idx := &Index{
indexFile: indexFile,
}
var err error
idx.f, err = os.Open(indexFile)
if err != nil {
return nil, err
}
var stat os.FileInfo
if stat, err = idx.f.Stat(); err != nil {
return nil, err
}
idx.size = stat.Size()
if idx.mmapHandle1, idx.mmapHandle2, err = mmap.Mmap(idx.f, int(idx.size)); err != nil {
return nil, err
}
idx.data = idx.mmapHandle1[:idx.size]
// Read number of keys and bytes per record
idx.baseDataID = binary.BigEndian.Uint64(idx.data[:8])
idx.keyCount = binary.BigEndian.Uint64(idx.data[8:16])
idx.bytesPerRec = int(idx.data[16])
idx.recMask = (uint64(1) << (8 * idx.bytesPerRec)) - 1
offset := 16 + 1 + int(idx.keyCount)*idx.bytesPerRec
// Bucket count, bucketSize, leafSize
idx.bucketCount = binary.BigEndian.Uint64(idx.data[offset:])
offset += 8
idx.bucketSize = int(binary.BigEndian.Uint16(idx.data[offset:]))
offset += 2
idx.leafSize = binary.BigEndian.Uint16(idx.data[offset:])
offset += 2
idx.primaryAggrBound = idx.leafSize * uint16(math.Max(2, math.Ceil(0.35*float64(idx.leafSize)+1./2.)))
if idx.leafSize < 7 {
idx.secondaryAggrBound = idx.primaryAggrBound * 2
} else {
idx.secondaryAggrBound = idx.primaryAggrBound * uint16(math.Ceil(0.21*float64(idx.leafSize)+9./10.))
}
// Salt
idx.salt = binary.BigEndian.Uint32(idx.data[offset:])
offset += 4
// Start seed
startSeedLen := int(idx.data[offset])
offset++
idx.startSeed = make([]uint64, startSeedLen)
for i := 0; i < startSeedLen; i++ {
idx.startSeed[i] = binary.BigEndian.Uint64(idx.data[offset:])
offset += 8
}
idx.enums = idx.data[offset] != 0
offset++
if idx.enums {
var size int
idx.offsetEf, size = eliasfano32.ReadEliasFano(idx.data[offset:])
offset += size
}
// Size of golomb rice params
golombParamSize := binary.BigEndian.Uint16(idx.data[offset:])
offset += 4
idx.golombRice = make([]uint32, golombParamSize)
for i := uint16(0); i < golombParamSize; i++ {
if i == 0 {
idx.golombRice[i] = (bijMemo[i] << 27) | bijMemo[i]
} else if i <= idx.leafSize {
idx.golombRice[i] = (bijMemo[i] << 27) | (uint32(1) << 16) | bijMemo[i]
} else {
computeGolombRice(i, idx.golombRice, idx.leafSize, idx.primaryAggrBound, idx.secondaryAggrBound)
}
}
l := binary.BigEndian.Uint64(idx.data[offset:])
offset += 8
p := (*[maxDataSize / 8]uint64)(unsafe.Pointer(&idx.data[offset]))
idx.grData = p[:l]
offset += 8 * int(l)
idx.ef.Read(idx.data[offset:])
return idx, nil
}
func (idx *Index) Size() int64 {
return idx.size
}
func (idx *Index) BaseDataID() uint64 { return idx.baseDataID }
func (idx *Index) Close() error {
if err := mmap.Munmap(idx.mmapHandle1, idx.mmapHandle2); err != nil {
return err
}
if err := idx.f.Close(); err != nil {
return err
}
return nil
}
func (idx *Index) skipBits(m uint16) int {
return int(idx.golombRice[m] & 0xffff)
}
func (idx *Index) skipNodes(m uint16) int {
return int(idx.golombRice[m]>>16) & 0x7FF
}
// golombParam returns the optimal Golomb parameter to use for encoding
// salt for the part of the hash function separating m elements. It is based on
// calculations with assumptions that we draw hash functions at random
func (idx *Index) golombParam(m uint16) int {
return int(idx.golombRice[m] >> 27)
}
func (idx *Index) Empty() bool {
return idx.keyCount == 0
}
func (idx *Index) KeyCount() uint64 {
return idx.keyCount
}
// Lookup is not thread-safe because it used id.hasher
func (idx *Index) Lookup(bucketHash, fingerprint uint64) uint64 {
if idx.keyCount == 0 {
panic("no Lookup should be done when keyCount==0, please use Empty function to guard")
}
if idx.keyCount == 1 {
return 0
}
var gr GolombRiceReader
gr.data = idx.grData
bucket := remap(bucketHash, idx.bucketCount)
cumKeys, cumKeysNext, bitPos := idx.ef.Get3(bucket)
m := uint16(cumKeysNext - cumKeys) // Number of keys in this bucket
gr.ReadReset(int(bitPos), idx.skipBits(m))
var level int
for m > idx.secondaryAggrBound { // fanout = 2
d := gr.ReadNext(idx.golombParam(m))
hmod := remap16(remix(fingerprint+idx.startSeed[level]+d), m)
split := (((m+1)/2 + idx.secondaryAggrBound - 1) / idx.secondaryAggrBound) * idx.secondaryAggrBound
if hmod < split {
m = split
} else {
gr.SkipSubtree(idx.skipNodes(split), idx.skipBits(split))
m -= split
cumKeys += uint64(split)
}
level++
}
if m > idx.primaryAggrBound {
d := gr.ReadNext(idx.golombParam(m))
hmod := remap16(remix(fingerprint+idx.startSeed[level]+d), m)
part := hmod / idx.primaryAggrBound
if idx.primaryAggrBound < m-part*idx.primaryAggrBound {
m = idx.primaryAggrBound
} else {
m = m - part*idx.primaryAggrBound
}
cumKeys += uint64(idx.primaryAggrBound * part)
if part != 0 {
gr.SkipSubtree(idx.skipNodes(idx.primaryAggrBound)*int(part), idx.skipBits(idx.primaryAggrBound)*int(part))
}
level++
}
if m > idx.leafSize {
d := gr.ReadNext(idx.golombParam(m))
hmod := remap16(remix(fingerprint+idx.startSeed[level]+d), m)
part := hmod / idx.leafSize
if idx.leafSize < m-part*idx.leafSize {
m = idx.leafSize
} else {
m = m - part*idx.leafSize
}
cumKeys += uint64(idx.leafSize * part)
if part != 0 {
gr.SkipSubtree(int(part), idx.skipBits(idx.leafSize)*int(part))
}
level++
}
b := gr.ReadNext(idx.golombParam(m))
rec := int(cumKeys) + int(remap16(remix(fingerprint+idx.startSeed[level]+b), m))
return binary.BigEndian.Uint64(idx.data[1+8+idx.bytesPerRec*(rec+1):]) & idx.recMask
}
// OrdinalLookup returns the offset of i-th element in the index
// Perfect hash table lookup is not performed, only access to the
// Elias-Fano structure containing all offsets.
func (idx *Index) OrdinalLookup(i uint64) uint64 {
return idx.offsetEf.Get(i)
}
func (idx *Index) ExtractOffsets() map[uint64]uint64 {
m := map[uint64]uint64{}
pos := 1 + 8 + idx.bytesPerRec
for rec := uint64(0); rec < idx.keyCount; rec++ {
offset := binary.BigEndian.Uint64(idx.data[pos:]) & idx.recMask
m[offset] = 0
pos += idx.bytesPerRec
}
return m
}
func (idx *Index) RewriteWithOffsets(w *bufio.Writer, m map[uint64]uint64) error {
// New max offset
var maxOffset uint64
for _, offset := range m {
if offset > maxOffset {
maxOffset = offset
}
}
bytesPerRec := (bits.Len64(maxOffset) + 7) / 8
var numBuf [8]byte
// Write baseDataID
binary.BigEndian.PutUint64(numBuf[:], idx.baseDataID)
if _, err := w.Write(numBuf[:]); err != nil {
return fmt.Errorf("write number of keys: %w", err)
}
// Write number of keys
binary.BigEndian.PutUint64(numBuf[:], idx.keyCount)
if _, err := w.Write(numBuf[:]); err != nil {
return fmt.Errorf("write number of keys: %w", err)
}
// Write number of bytes per index record
if err := w.WriteByte(byte(bytesPerRec)); err != nil {
return fmt.Errorf("write bytes per record: %w", err)
}
pos := 1 + 8 + idx.bytesPerRec
for rec := uint64(0); rec < idx.keyCount; rec++ {
offset := binary.BigEndian.Uint64(idx.data[pos:]) & idx.recMask
pos += idx.bytesPerRec
binary.BigEndian.PutUint64(numBuf[:], m[offset])
if _, err := w.Write(numBuf[8-bytesPerRec:]); err != nil {
return err
}
}
// Write the rest as it is (TODO - wrong for indices with enums)
if _, err := w.Write(idx.data[16+1+int(idx.keyCount)*idx.bytesPerRec:]); err != nil {
return err
}
return nil
}