memstore changes

- inttegrate changes related to db + access count
- simplify API , only Get/Put no add/find
- signal need to retrieve from db with chunk.update = true
- consistent naming
- unix line endings
This commit is contained in:
zelig 2015-02-01 19:41:27 +01:00
parent 4d3af2ca33
commit 2c464282cd

View file

@ -1,301 +1,296 @@
// memory storage layer for the package blockhash
package bzz
import (
"bytes"
)
const (
maxEntries = 500 // max number of stored (cached) blocks
memTreeLW = 2 // log2(subtree count) of the subtrees
memTreeFLW = 14 // log2(subtree count) of the root layer
dbForceUpdateAccessCnt = 1000
)
type dpaMemStorage struct {
memtree *dpaMemTree
entry_cnt uint // stored entries
access_cnt uint64 // access counter; oldest is thrown away when full
dbAccessCnt uint64
}
/*
a hash prefix subtree containing subtrees or one storage entry (but never both)
- access[0] stores the smallest (oldest) access count value in this subtree
- if it contains more subtrees and its subtree count is at least 4, access[1:2]
stores the smallest access count in the first and second halves of subtrees
(so that access[0] = min(access[1], access[2])
- likewise, if subtree count is at least 8,
access[1] = min(access[3], access[4])
access[2] = min(access[5], access[6])
(access[] is a binary tree inside the multi-bit leveled hash tree)
*/
func (x Key) Size() uint {
return uint(len(x))
}
func (x Key) isEqual(y Key) bool {
return bytes.Compare(x, y) == 0
}
func (h Key) bits(i, j uint) uint {
ii := i >> 3
jj := i & 7
if ii >= h.Size() {
return 0
}
if jj+j <= 8 {
return uint((h[ii] >> jj) & ((1 << j) - 1))
}
res := uint(h[ii] >> jj)
jj = 8 - jj
j -= jj
for j != 0 {
ii++
if j < 8 {
res += uint(h[ii]&((1<<j)-1)) << jj
return res
}
res += uint(h[ii]) << jj
jj += 8
j -= 8
}
return res
}
type dpaMemTree struct {
subtree []*dpaMemTree
parent *dpaMemTree
parent_idx uint
bits uint // log2(subtree count)
width uint // subtree count
entry *Chunk // if subtrees are present, entry should be nil
lastDBaccess uint64
access []uint64
}
func newTreeNode(b uint, parent *dpaMemTree, pidx uint) (node *dpaMemTree) {
node = new(dpaMemTree)
node.bits = b
node.width = 1 << uint(b)
node.subtree = make([]*dpaMemTree, node.width)
node.access = make([]uint64, node.width-1)
node.parent = parent
node.parent_idx = pidx
if parent != nil {
parent.subtree[pidx] = node
}
return node
}
func (node *dpaMemTree) update_access(a uint64) {
aidx := uint(0)
var aa uint64
oa := node.access[0]
for node.access[aidx] == oa {
node.access[aidx] = a
if aidx > 0 {
aa = node.access[((aidx-1)^1)+1]
aidx = (aidx - 1) >> 1
} else {
pidx := node.parent_idx
node = node.parent
if node == nil {
return
}
nn := node.subtree[pidx^1]
if nn != nil {
aa = nn.access[0]
} else {
aa = 0
}
aidx = (node.width + pidx - 2) >> 1
}
if (aa != 0) && (aa < a) {
a = aa
}
}
}
func (s *dpaMemStorage) add(entry *Chunk) {
s.access_cnt++
node := s.memtree
bitpos := uint(0)
for node.entry == nil {
l := entry.Key.bits(bitpos, node.bits)
st := node.subtree[l]
if st == nil {
st = newTreeNode(memTreeLW, node, l)
bitpos += node.bits
node = st
break
}
bitpos += node.bits
node = st
}
if node.entry != nil {
if node.entry.Key.isEqual(entry.Key) {
node.update_access(s.access_cnt)
return
}
for node.entry != nil {
l := node.entry.Key.bits(bitpos, node.bits)
st := node.subtree[l]
if st == nil {
st = newTreeNode(memTreeLW, node, l)
}
st.entry = node.entry
node.entry = nil
st.update_access(node.access[0])
l = entry.Key.bits(bitpos, node.bits)
st = node.subtree[l]
if st == nil {
st = newTreeNode(memTreeLW, node, l)
}
bitpos += node.bits
node = st
}
}
node.entry = entry
node.lastDBaccess = s.dbAccessCnt
node.update_access(s.access_cnt)
s.entry_cnt++
}
func (s *dpaMemStorage) find(hash Key) (entry *Chunk) {
node := s.memtree
bitpos := uint(0)
for node.entry == nil {
l := hash.bits(bitpos, node.bits)
st := node.subtree[l]
if st == nil {
return nil
}
bitpos += node.bits
node = st
}
if node.entry.Key.isEqual(hash) {
s.access_cnt++
node.update_access(s.access_cnt)
return node.entry
} else {
return nil
}
}
func (s *dpaMemStorage) remove_oldest() {
node := s.memtree
for node.entry == nil {
aidx := uint(0)
av := node.access[aidx]
for aidx < node.width/2-1 {
if av == node.access[aidx*2+1] {
node.access[aidx] = node.access[aidx*2+2]
aidx = aidx*2 + 1
} else if av == node.access[aidx*2+2] {
node.access[aidx] = node.access[aidx*2+1]
aidx = aidx*2 + 2
} else {
panic(nil)
}
}
pidx := aidx*2 + 2 - node.width
if (node.subtree[pidx] != nil) && (av == node.subtree[pidx].access[0]) {
if node.subtree[pidx+1] != nil {
node.access[aidx] = node.subtree[pidx+1].access[0]
} else {
node.access[aidx] = 0
}
} else if (node.subtree[pidx+1] != nil) && (av == node.subtree[pidx+1].access[0]) {
if node.subtree[pidx] != nil {
node.access[aidx] = node.subtree[pidx].access[0]
} else {
node.access[aidx] = 0
}
pidx++
} else {
panic(nil)
}
//fmt.Println(pidx)
node = node.subtree[pidx]
}
node.entry = nil
s.entry_cnt--
node.access[0] = 0
//---
aidx := uint(0)
for {
aa := node.access[aidx]
if aidx > 0 {
aidx = (aidx - 1) >> 1
} else {
pidx := node.parent_idx
node = node.parent
if node == nil {
return
}
aidx = (node.width + pidx - 2) >> 1
}
if (aa != 0) && ((aa < node.access[aidx]) || (node.access[aidx] == 0)) {
node.access[aidx] = aa
}
}
}
func (s *dpaMemStorage) Put(req *Chunk) error {
if s.entry_cnt >= maxEntries {
s.remove_oldest()
}
s.add(req)
return nil
}
func (s *dpaMemStorage) Get(req *Chunk) {
entry := s.find(req.Key)
if entry == nil {
}
}
func (s *dpaMemStorage) Init() {
s.memtree = newTreeNode(memTreeFLW, nil, 0)
}
// memory storage layer for the package blockhash
package bzz
import (
"bytes"
)
const (
maxEntries = 500 // max number of stored (cached) blocks
memTreeLW = 2 // log2(subtree count) of the subtrees
memTreeFLW = 14 // log2(subtree count) of the root layer
dbForceUpdateAccessCnt = 1000
)
type memStore struct {
memtree *memTree
entryCnt uint // stored entries
accessCnt uint64 // access counter; oldest is thrown away when full
dbAccessCnt uint64
}
/*
a hash prefix subtree containing subtrees or one storage entry (but never both)
- access[0] stores the smallest (oldest) access count value in this subtree
- if it contains more subtrees and its subtree count is at least 4, access[1:2]
stores the smallest access count in the first and second halves of subtrees
(so that access[0] = min(access[1], access[2])
- likewise, if subtree count is at least 8,
access[1] = min(access[3], access[4])
access[2] = min(access[5], access[6])
(access[] is a binary tree inside the multi-bit leveled hash tree)
*/
func (x Key) Size() uint {
return uint(len(x))
}
func (x Key) isEqual(y Key) bool {
return bytes.Compare(x, y) == 0
}
func (h Key) bits(i, j uint) uint {
ii := i >> 3
jj := i & 7
if ii >= h.Size() {
return 0
}
if jj+j <= 8 {
return uint((h[ii] >> jj) & ((1 << j) - 1))
}
res := uint(h[ii] >> jj)
jj = 8 - jj
j -= jj
for j != 0 {
ii++
if j < 8 {
res += uint(h[ii]&((1<<j)-1)) << jj
return res
}
res += uint(h[ii]) << jj
jj += 8
j -= 8
}
return res
}
type memTree struct {
subtree []*memTree
parent *memTree
parentIdx uint
bits uint // log2(subtree count)
width uint // subtree count
entry *Chunk // if subtrees are present, entry should be nil
lastDBaccess uint64
access []uint64
}
func newMemTree(b uint, parent *memTree, pidx uint) (node *memTree) {
node = new(memTree)
node.bits = b
node.width = 1 << uint(b)
node.subtree = make([]*memTree, node.width)
node.access = make([]uint64, node.width-1)
node.parent = parent
node.parentIdx = pidx
if parent != nil {
parent.subtree[pidx] = node
}
return node
}
func (node *memTree) updateAccess(a uint64) {
aidx := uint(0)
var aa uint64
oa := node.access[0]
for node.access[aidx] == oa {
node.access[aidx] = a
if aidx > 0 {
aa = node.access[((aidx-1)^1)+1]
aidx = (aidx - 1) >> 1
} else {
pidx := node.parentIdx
node = node.parent
if node == nil {
return
}
nn := node.subtree[pidx^1]
if nn != nil {
aa = nn.access[0]
} else {
aa = 0
}
aidx = (node.width + pidx - 2) >> 1
}
if (aa != 0) && (aa < a) {
a = aa
}
}
}
func (s *memStore) Put(entry *Chunk) (err error) {
if s.entryCnt >= maxEntries {
s.removeOldest()
}
s.accessCnt++
node := s.memtree
bitpos := uint(0)
for node.entry == nil {
l := entry.Key.bits(bitpos, node.bits)
st := node.subtree[l]
if st == nil {
st = newMemTree(memTreeLW, node, l)
bitpos += node.bits
node = st
break
}
bitpos += node.bits
node = st
}
if node.entry != nil {
if node.entry.Key.isEqual(entry.Key) {
node.updateAccess(s.accessCnt)
return
}
for node.entry != nil {
l := node.entry.Key.bits(bitpos, node.bits)
st := node.subtree[l]
if st == nil {
st = newMemTree(memTreeLW, node, l)
}
st.entry = node.entry
node.entry = nil
st.updateAccess(node.access[0])
l = entry.Key.bits(bitpos, node.bits)
st = node.subtree[l]
if st == nil {
st = newMemTree(memTreeLW, node, l)
}
bitpos += node.bits
node = st
}
}
node.entry = entry
node.lastDBaccess = s.dbAccessCnt
node.updateAccess(s.accessCnt)
s.entryCnt++
return
}
func (s *memStore) Get(chunk *Chunk) (err error) {
hash := chunk.Key
node := s.memtree
bitpos := uint(0)
for node.entry == nil {
l := hash.bits(bitpos, node.bits)
st := node.subtree[l]
if st == nil {
return nil
}
bitpos += node.bits
node = st
}
if node.entry.Key.isEqual(hash) {
s.accessCnt++
node.updateAccess(s.accessCnt)
if s.dbAccessCnt-node.lastDBaccess > dbForceUpdateAccessCnt {
s.dbAccessCnt++
node.lastDBaccess = s.dbAccessCnt
chunk.update = true
}
chunk.Data = node.entry.Data
chunk.Size = node.entry.Size
} else {
err = notFound
}
return
}
func (s *memStore) removeOldest() {
node := s.memtree
for node.entry == nil {
aidx := uint(0)
av := node.access[aidx]
for aidx < node.width/2-1 {
if av == node.access[aidx*2+1] {
node.access[aidx] = node.access[aidx*2+2]
aidx = aidx*2 + 1
} else if av == node.access[aidx*2+2] {
node.access[aidx] = node.access[aidx*2+1]
aidx = aidx*2 + 2
} else {
panic(nil)
}
}
pidx := aidx*2 + 2 - node.width
if (node.subtree[pidx] != nil) && (av == node.subtree[pidx].access[0]) {
if node.subtree[pidx+1] != nil {
node.access[aidx] = node.subtree[pidx+1].access[0]
} else {
node.access[aidx] = 0
}
} else if (node.subtree[pidx+1] != nil) && (av == node.subtree[pidx+1].access[0]) {
if node.subtree[pidx] != nil {
node.access[aidx] = node.subtree[pidx].access[0]
} else {
node.access[aidx] = 0
}
pidx++
} else {
panic(nil)
}
//fmt.Println(pidx)
node = node.subtree[pidx]
}
node.entry = nil
s.entryCnt--
node.access[0] = 0
//---
aidx := uint(0)
for {
aa := node.access[aidx]
if aidx > 0 {
aidx = (aidx - 1) >> 1
} else {
pidx := node.parentIdx
node = node.parent
if node == nil {
return
}
aidx = (node.width + pidx - 2) >> 1
}
if (aa != 0) && ((aa < node.access[aidx]) || (node.access[aidx] == 0)) {
node.access[aidx] = aa
}
}
}
func (s *memStore) Init() {
s.memtree = newMemTree(memTreeFLW, nil, 0)
}