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trie: approximate the wasted cache metaspace closer

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Péter Szilágyi 2018-11-22 14:09:04 +02:00
parent 1528b791ac
commit 4a4abc41d4
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GPG Key ID: E9AE538CEDF8293D
1 changed files with 44 additions and 14 deletions
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58
trie/database.go
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@ -21,6 +21,7 @@ import (
"errors"
"fmt"
"io"
"reflect"
"sync"
"time"
@ -84,7 +85,8 @@ type Database struct {
flushnodes uint64 // Nodes flushed since last commit
flushsize common.StorageSize // Data storage flushed since last commit
dirtiesSize common.StorageSize // Storage size of the dirty node cache (exc. flushlist)
dirtiesSize common.StorageSize // Storage size of the dirty node cache (exc. metadata)
childrenSize common.StorageSize // Storage size of the external children tracking
preimagesSize common.StorageSize // Storage size of the preimages cache
lock sync.RWMutex
@ -146,6 +148,15 @@ type cachedNode struct {
flushNext common.Hash // Next node in the flush-list
}
// cachedNodeSize is the raw size of a cachedNode data structure without any
// node data included. It's an approximate size, but should be a lot better
// than not counting them.
var cachedNodeSize = int(reflect.TypeOf(cachedNode{}).Size())
// cachedNodeChildrenSize is the raw size of an initialized but empty external
// reference map.
const cachedNodeChildrenSize = 48
// rlp returns the raw rlp encoded blob of the cached node, either directly from
// the cache, or by regenerating it from the collapsed node.
func (n *cachedNode) rlp() []byte {
@ -300,9 +311,11 @@ func NewDatabaseWithCache(diskdb ethdb.KeyValueStore, cache int) *Database {
})
}
return &Database{
diskdb: diskdb,
cleans: cleans,
dirties: map[common.Hash]*cachedNode{{}: {}},
diskdb: diskdb,
cleans: cleans,
dirties: map[common.Hash]*cachedNode{{}: {
children: make(map[common.Hash]uint16),
}},
preimages: make(map[common.Hash][]byte),
}
}
@ -491,11 +504,15 @@ func (db *Database) reference(child common.Hash, parent common.Hash) {
// If the reference already exists, only duplicate for roots
if db.dirties[parent].children == nil {
db.dirties[parent].children = make(map[common.Hash]uint16)
db.childrenSize += cachedNodeChildrenSize
} else if _, ok = db.dirties[parent].children[child]; ok && parent != (common.Hash{}) {
return
}
node.parents++
db.dirties[parent].children[child]++
if db.dirties[parent].children[child] == 1 {
db.childrenSize += common.HashLength + 2 // uint16 counter
}
}
// Dereference removes an existing reference from a root node.
@ -532,6 +549,7 @@ func (db *Database) dereference(child common.Hash, parent common.Hash) {
node.children[child]--
if node.children[child] == 0 {
delete(node.children, child)
db.childrenSize -= (common.HashLength + 2) // uint16 counter
}
}
// If the child does not exist, it's a previously committed node.
@ -566,6 +584,9 @@ func (db *Database) dereference(child common.Hash, parent common.Hash) {
}
delete(db.dirties, child)
db.dirtiesSize -= common.StorageSize(common.HashLength + int(node.size))
if node.children != nil {
db.childrenSize -= cachedNodeChildrenSize
}
}
}
@ -584,8 +605,9 @@ func (db *Database) Cap(limit common.StorageSize) error {
// db.dirtiesSize only contains the useful data in the cache, but when reporting
// the total memory consumption, the maintenance metadata is also needed to be
// counted. For every useful node, we track 2 extra hashes as the flushlist.
size := db.dirtiesSize + common.StorageSize((len(db.dirties)-1)*2*common.HashLength)
// counted.
size := db.dirtiesSize + common.StorageSize((len(db.dirties)-1)*cachedNodeSize)
size += db.childrenSize - common.StorageSize(len(db.dirties[common.Hash{}].children)*(common.HashLength+2))
// If the preimage cache got large enough, push to disk. If it's still small
// leave for later to deduplicate writes.
@ -621,10 +643,12 @@ func (db *Database) Cap(limit common.StorageSize) error {
batch.Reset()
}
// Iterate to the next flush item, or abort if the size cap was achieved. Size
// is the total size, including both the useful cached data (hash -> blob), as
// well as the flushlist metadata (2*hash). When flushing items from the cache,
// we need to reduce both.
size -= common.StorageSize(3*common.HashLength + int(node.size))
// is the total size, including the useful cached data (hash -> blob), the
// cache item metadata, as well as external children mappings.
size -= common.StorageSize(common.HashLength + int(node.size) + cachedNodeSize)
if node.children != nil {
size -= common.StorageSize(cachedNodeChildrenSize + len(node.children)*(common.HashLength+2))
}
oldest = node.flushNext
}
// Flush out any remainder data from the last batch
@ -646,6 +670,9 @@ func (db *Database) Cap(limit common.StorageSize) error {
db.oldest = node.flushNext
db.dirtiesSize -= common.StorageSize(common.HashLength + int(node.size))
if node.children != nil {
db.childrenSize -= common.StorageSize(cachedNodeChildrenSize + len(node.children)*(common.HashLength+2))
}
}
if db.oldest != (common.Hash{}) {
db.dirties[db.oldest].flushPrev = common.Hash{}
@ -803,7 +830,9 @@ func (c *cleaner) Put(key []byte, rlp []byte) error {
// Remove the node from the dirty cache
delete(c.db.dirties, hash)
c.db.dirtiesSize -= common.StorageSize(common.HashLength + int(node.size))
if node.children != nil {
c.db.dirtiesSize -= common.StorageSize(cachedNodeChildrenSize + len(node.children)*(common.HashLength+2))
}
// Move the flushed node into the clean cache to prevent insta-reloads
if c.db.cleans != nil {
c.db.cleans.Set(string(hash[:]), rlp)
@ -823,9 +852,10 @@ func (db *Database) Size() (common.StorageSize, common.StorageSize) {
// db.dirtiesSize only contains the useful data in the cache, but when reporting
// the total memory consumption, the maintenance metadata is also needed to be
// counted. For every useful node, we track 2 extra hashes as the flushlist.
var flushlistSize = common.StorageSize((len(db.dirties) - 1) * 2 * common.HashLength)
return db.dirtiesSize + flushlistSize, db.preimagesSize
// counted.
var metadataSize = common.StorageSize((len(db.dirties) - 1) * cachedNodeSize)
var metarootRefs = common.StorageSize(len(db.dirties[common.Hash{}].children) * (common.HashLength + 2))
return db.dirtiesSize + db.childrenSize + metadataSize - metarootRefs, db.preimagesSize
}
// verifyIntegrity is a debug method to iterate over the entire trie stored in