mirror of https://github.com/ethereum/go-ethereum
core, trie: intermediate mempool between trie and database (#15857)
This commit reduces database I/O by not writing every state trie to disk.pull/16037/head
Péter Szilágyi
7 years ago
committed by
Felix Lange
parent
59336283c0
commit
55599ee95d
@ -0,0 +1,355 @@ |
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// Copyright 2017 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package trie |
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import ( |
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"sync" |
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"time" |
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"github.com/ethereum/go-ethereum/common" |
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"github.com/ethereum/go-ethereum/ethdb" |
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"github.com/ethereum/go-ethereum/log" |
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) |
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// secureKeyPrefix is the database key prefix used to store trie node preimages.
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var secureKeyPrefix = []byte("secure-key-") |
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// secureKeyLength is the length of the above prefix + 32byte hash.
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const secureKeyLength = 11 + 32 |
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// DatabaseReader wraps the Get and Has method of a backing store for the trie.
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type DatabaseReader interface { |
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// Get retrieves the value associated with key form the database.
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Get(key []byte) (value []byte, err error) |
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// Has retrieves whether a key is present in the database.
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Has(key []byte) (bool, error) |
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} |
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// Database is an intermediate write layer between the trie data structures and
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// the disk database. The aim is to accumulate trie writes in-memory and only
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// periodically flush a couple tries to disk, garbage collecting the remainder.
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type Database struct { |
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diskdb ethdb.Database // Persistent storage for matured trie nodes
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nodes map[common.Hash]*cachedNode // Data and references relationships of a node
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preimages map[common.Hash][]byte // Preimages of nodes from the secure trie
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seckeybuf [secureKeyLength]byte // Ephemeral buffer for calculating preimage keys
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gctime time.Duration // Time spent on garbage collection since last commit
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gcnodes uint64 // Nodes garbage collected since last commit
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gcsize common.StorageSize // Data storage garbage collected since last commit
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nodesSize common.StorageSize // Storage size of the nodes cache
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preimagesSize common.StorageSize // Storage size of the preimages cache
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lock sync.RWMutex |
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} |
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// cachedNode is all the information we know about a single cached node in the
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// memory database write layer.
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type cachedNode struct { |
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blob []byte // Cached data block of the trie node
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parents int // Number of live nodes referencing this one
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children map[common.Hash]int // Children referenced by this nodes
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} |
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// NewDatabase creates a new trie database to store ephemeral trie content before
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// its written out to disk or garbage collected.
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func NewDatabase(diskdb ethdb.Database) *Database { |
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return &Database{ |
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diskdb: diskdb, |
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nodes: map[common.Hash]*cachedNode{ |
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{}: {children: make(map[common.Hash]int)}, |
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}, |
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preimages: make(map[common.Hash][]byte), |
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} |
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} |
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// DiskDB retrieves the persistent storage backing the trie database.
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func (db *Database) DiskDB() DatabaseReader { |
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return db.diskdb |
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} |
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// Insert writes a new trie node to the memory database if it's yet unknown. The
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// method will make a copy of the slice.
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func (db *Database) Insert(hash common.Hash, blob []byte) { |
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db.lock.Lock() |
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defer db.lock.Unlock() |
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db.insert(hash, blob) |
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} |
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// insert is the private locked version of Insert.
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func (db *Database) insert(hash common.Hash, blob []byte) { |
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if _, ok := db.nodes[hash]; ok { |
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return |
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} |
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db.nodes[hash] = &cachedNode{ |
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blob: common.CopyBytes(blob), |
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children: make(map[common.Hash]int), |
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} |
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db.nodesSize += common.StorageSize(common.HashLength + len(blob)) |
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} |
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// insertPreimage writes a new trie node pre-image to the memory database if it's
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// yet unknown. The method will make a copy of the slice.
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//
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// Note, this method assumes that the database's lock is held!
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func (db *Database) insertPreimage(hash common.Hash, preimage []byte) { |
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if _, ok := db.preimages[hash]; ok { |
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return |
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} |
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db.preimages[hash] = common.CopyBytes(preimage) |
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db.preimagesSize += common.StorageSize(common.HashLength + len(preimage)) |
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} |
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// Node retrieves a cached trie node from memory. If it cannot be found cached,
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// the method queries the persistent database for the content.
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func (db *Database) Node(hash common.Hash) ([]byte, error) { |
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// Retrieve the node from cache if available
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db.lock.RLock() |
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node := db.nodes[hash] |
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db.lock.RUnlock() |
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if node != nil { |
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return node.blob, nil |
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} |
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// Content unavailable in memory, attempt to retrieve from disk
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return db.diskdb.Get(hash[:]) |
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} |
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// preimage retrieves a cached trie node pre-image from memory. If it cannot be
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// found cached, the method queries the persistent database for the content.
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func (db *Database) preimage(hash common.Hash) ([]byte, error) { |
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// Retrieve the node from cache if available
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db.lock.RLock() |
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preimage := db.preimages[hash] |
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db.lock.RUnlock() |
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if preimage != nil { |
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return preimage, nil |
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} |
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// Content unavailable in memory, attempt to retrieve from disk
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return db.diskdb.Get(db.secureKey(hash[:])) |
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} |
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// secureKey returns the database key for the preimage of key, as an ephemeral
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// buffer. The caller must not hold onto the return value because it will become
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// invalid on the next call.
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func (db *Database) secureKey(key []byte) []byte { |
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buf := append(db.seckeybuf[:0], secureKeyPrefix...) |
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buf = append(buf, key...) |
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return buf |
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} |
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// Nodes retrieves the hashes of all the nodes cached within the memory database.
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// This method is extremely expensive and should only be used to validate internal
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// states in test code.
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func (db *Database) Nodes() []common.Hash { |
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db.lock.RLock() |
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defer db.lock.RUnlock() |
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var hashes = make([]common.Hash, 0, len(db.nodes)) |
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for hash := range db.nodes { |
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if hash != (common.Hash{}) { // Special case for "root" references/nodes
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hashes = append(hashes, hash) |
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} |
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} |
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return hashes |
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} |
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// Reference adds a new reference from a parent node to a child node.
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func (db *Database) Reference(child common.Hash, parent common.Hash) { |
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db.lock.RLock() |
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defer db.lock.RUnlock() |
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db.reference(child, parent) |
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} |
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// reference is the private locked version of Reference.
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func (db *Database) reference(child common.Hash, parent common.Hash) { |
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// If the node does not exist, it's a node pulled from disk, skip
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node, ok := db.nodes[child] |
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if !ok { |
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return |
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} |
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// If the reference already exists, only duplicate for roots
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if _, ok = db.nodes[parent].children[child]; ok && parent != (common.Hash{}) { |
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return |
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} |
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node.parents++ |
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db.nodes[parent].children[child]++ |
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} |
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// Dereference removes an existing reference from a parent node to a child node.
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func (db *Database) Dereference(child common.Hash, parent common.Hash) { |
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db.lock.Lock() |
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defer db.lock.Unlock() |
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nodes, storage, start := len(db.nodes), db.nodesSize, time.Now() |
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db.dereference(child, parent) |
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db.gcnodes += uint64(nodes - len(db.nodes)) |
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db.gcsize += storage - db.nodesSize |
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db.gctime += time.Since(start) |
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log.Debug("Dereferenced trie from memory database", "nodes", nodes-len(db.nodes), "size", storage-db.nodesSize, "time", time.Since(start), |
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"gcnodes", db.gcnodes, "gcsize", db.gcsize, "gctime", db.gctime, "livenodes", len(db.nodes), "livesize", db.nodesSize) |
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} |
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// dereference is the private locked version of Dereference.
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func (db *Database) dereference(child common.Hash, parent common.Hash) { |
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// Dereference the parent-child
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node := db.nodes[parent] |
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node.children[child]-- |
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if node.children[child] == 0 { |
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delete(node.children, child) |
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} |
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// If the node does not exist, it's a previously committed node.
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node, ok := db.nodes[child] |
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if !ok { |
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return |
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} |
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// If there are no more references to the child, delete it and cascade
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node.parents-- |
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if node.parents == 0 { |
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for hash := range node.children { |
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db.dereference(hash, child) |
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} |
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delete(db.nodes, child) |
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db.nodesSize -= common.StorageSize(common.HashLength + len(node.blob)) |
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} |
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} |
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// Commit iterates over all the children of a particular node, writes them out
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// to disk, forcefully tearing down all references in both directions.
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//
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// As a side effect, all pre-images accumulated up to this point are also written.
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func (db *Database) Commit(node common.Hash, report bool) error { |
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// Create a database batch to flush persistent data out. It is important that
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// outside code doesn't see an inconsistent state (referenced data removed from
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// memory cache during commit but not yet in persistent storage). This is ensured
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// by only uncaching existing data when the database write finalizes.
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db.lock.RLock() |
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start := time.Now() |
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batch := db.diskdb.NewBatch() |
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// Move all of the accumulated preimages into a write batch
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for hash, preimage := range db.preimages { |
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if err := batch.Put(db.secureKey(hash[:]), preimage); err != nil { |
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log.Error("Failed to commit preimage from trie database", "err", err) |
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db.lock.RUnlock() |
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return err |
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} |
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if batch.ValueSize() > ethdb.IdealBatchSize { |
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if err := batch.Write(); err != nil { |
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return err |
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} |
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batch.Reset() |
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} |
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} |
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// Move the trie itself into the batch, flushing if enough data is accumulated
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nodes, storage := len(db.nodes), db.nodesSize+db.preimagesSize |
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if err := db.commit(node, batch); err != nil { |
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log.Error("Failed to commit trie from trie database", "err", err) |
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db.lock.RUnlock() |
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return err |
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} |
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// Write batch ready, unlock for readers during persistence
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if err := batch.Write(); err != nil { |
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log.Error("Failed to write trie to disk", "err", err) |
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db.lock.RUnlock() |
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return err |
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} |
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db.lock.RUnlock() |
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// Write successful, clear out the flushed data
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db.lock.Lock() |
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defer db.lock.Unlock() |
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db.preimages = make(map[common.Hash][]byte) |
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db.preimagesSize = 0 |
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db.uncache(node) |
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logger := log.Info |
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if !report { |
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logger = log.Debug |
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} |
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logger("Persisted trie from memory database", "nodes", nodes-len(db.nodes), "size", storage-db.nodesSize, "time", time.Since(start), |
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"gcnodes", db.gcnodes, "gcsize", db.gcsize, "gctime", db.gctime, "livenodes", len(db.nodes), "livesize", db.nodesSize) |
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// Reset the garbage collection statistics
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db.gcnodes, db.gcsize, db.gctime = 0, 0, 0 |
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return nil |
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} |
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// commit is the private locked version of Commit.
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func (db *Database) commit(hash common.Hash, batch ethdb.Batch) error { |
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// If the node does not exist, it's a previously committed node
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node, ok := db.nodes[hash] |
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if !ok { |
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return nil |
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} |
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for child := range node.children { |
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if err := db.commit(child, batch); err != nil { |
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return err |
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} |
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} |
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if err := batch.Put(hash[:], node.blob); err != nil { |
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return err |
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} |
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// If we've reached an optimal match size, commit and start over
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if batch.ValueSize() >= ethdb.IdealBatchSize { |
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if err := batch.Write(); err != nil { |
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return err |
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} |
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batch.Reset() |
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} |
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return nil |
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} |
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// uncache is the post-processing step of a commit operation where the already
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// persisted trie is removed from the cache. The reason behind the two-phase
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// commit is to ensure consistent data availability while moving from memory
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// to disk.
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func (db *Database) uncache(hash common.Hash) { |
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// If the node does not exist, we're done on this path
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node, ok := db.nodes[hash] |
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if !ok { |
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return |
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} |
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// Otherwise uncache the node's subtries and remove the node itself too
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for child := range node.children { |
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db.uncache(child) |
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} |
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delete(db.nodes, hash) |
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db.nodesSize -= common.StorageSize(common.HashLength + len(node.blob)) |
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} |
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// Size returns the current storage size of the memory cache in front of the
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// persistent database layer.
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func (db *Database) Size() common.StorageSize { |
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db.lock.RLock() |
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defer db.lock.RUnlock() |
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return db.nodesSize + db.preimagesSize |
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} |
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