yonote/yjs
23
0
Fork 0
Code Pull Requests 1 Releases Activity

implemented small lookup buffer. This heavily improves lookups for slow databases

Browse Source
This commit is contained in:
Kevin Jahns 2016-01-22 14:09:51 +01:00
parent 37ac7787d0
commit 1b3f5443b3
2 changed files with 165 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
src/Database.js
View File

@ -403,16 +403,12 @@ module.exports = function (Y /* :any */) {
}
}
requestTransaction (makeGen/* :any */, callImmediately) {
if (false || callImmediately) { // TODO: decide whether this is ok or not..
this.waitingTransactions.push(makeGen)
if (!this.transactionInProgress) {
this.transactionInProgress = true
this.waitingTransactions.push(makeGen)
if (!this.transactionInProgress) {
this.transactionInProgress = true
if (true || callImmediately) { // TODO: decide whether this is ok or not..
this.transact(this.getNextRequest())
}
} else {
this.waitingTransactions.push(makeGen)
if (!this.transactionInProgress) {
this.transactionInProgress = true
} else {
var self = this
setTimeout(function () {
self.transact(self.getNextRequest())

160
src/Utils.js
View File

@ -225,4 +225,164 @@ module.exports = function (Y /* : any*/) {
}
}
Y.utils.compareIds = compareIds
function createEmptyOpsArray (n) {
var a = new Array(n)
for (var i = 0; i < a.length; i++) {
a[i] = {
id: [null, null]
}
}
return a
}
function createSmallLookupBuffer (Store) {
/*
This buffer implements a very small buffer that temporarily stores operations
after they are read / before they are written.
The buffer basically implements FIFO. Often requested lookups will be re-queued every time they are looked up / written.
It can speed up lookups on Operation Stores and State Stores. But it does not require notable use of memory or processing power.
Good for os and ss, bot not for ds (because it often uses methods that require a flush)
I tried to optimize this for performance, therefore no highlevel operations.
*/
class SmallLookupBuffer extends Store {
constructor (read, write) {
super()
this.writeBuffer = createEmptyOpsArray(5)
this.readBuffer = createEmptyOpsArray(10)
}
* find (id) {
var i, r
for (i = this.readBuffer.length - 1; i >= 0; i--) {
r = this.readBuffer[i]
// we don't have to use compareids, because id is always defined!
if (r.id[1] === id[1] && r.id[0] === id[0]) {
// found r
// move r to the end of readBuffer
for (; i < this.readBuffer.length - 1; i++) {
this.readBuffer[i] = this.readBuffer[i + 1]
}
this.readBuffer[this.readBuffer.length - 1] = r
return r
}
}
var o
for (i = this.writeBuffer.length - 1; i >= 0; i--) {
r = this.writeBuffer[i]
if (r.id[1] === id[1] && r.id[0] === id[0]) {
o = r
break
}
}
if (i < 0) {
// did not reach break in last loop
// read id and put it to the end of readBuffer
o = yield* super.find(id)
}
if (o != null) {
for (i = 0; i < this.readBuffer.length - 1; i++) {
this.readBuffer[i] = this.readBuffer[i + 1]
}
this.readBuffer[this.readBuffer.length - 1] = o
}
return o
}
* put (o) {
var id = o.id
var i, r // helper variables
for (i = this.writeBuffer.length - 1; i >= 0; i--) {
r = this.writeBuffer[i]
if (r.id[1] === id[1] && r.id[0] === id[0]) {
// is already in buffer
// forget r, and move o to the end of writeBuffer
for (; i < this.writeBuffer.length - 1; i++) {
this.writeBuffer[i] = this.writeBuffer[i + 1]
}
this.writeBuffer[this.writeBuffer.length - 1] = o
break
}
}
if (i < 0) {
// did not reach break in last loop
// write writeBuffer[0]
var write = this.writeBuffer[0]
if (write.id[0] !== null) {
yield* super.put(write)
}
// put o to the end of writeBuffer
for (i = 0; i < this.writeBuffer.length - 1; i++) {
this.writeBuffer[i] = this.writeBuffer[i + 1]
}
this.writeBuffer[this.writeBuffer.length - 1] = o
}
// check readBuffer for every occurence of o.id, overwrite if found
// whether found or not, we'll append o to the readbuffer
for (i = 0; i < this.readBuffer.length - 1; i++) {
r = this.readBuffer[i + 1]
if (r.id[1] === id[1] && r.id[0] === id[0]) {
this.readBuffer[i] = o
} else {
this.readBuffer[i] = r
}
}
this.readBuffer[this.readBuffer.length - 1] = o
}
* delete (id) {
var i, r
for (i = 0; i < this.readBuffer.length; i++) {
r = this.readBuffer[i]
if (r.id[1] === id[1] && r.id[0] === id[0]) {
this.readBuffer[i] = {
id: [null, null]
}
}
}
for (i = 0; i < this.writeBuffer.length; i++) {
r = this.writeBuffer[i]
if (r.id[1] === id[1] && r.id[0] === id[0]) {
this.writeBuffer[i] = {
id: [null, null]
}
}
}
yield* super.delete(id)
}
* findWithLowerBound () {
yield* this.flush()
return yield* super.findWithLowerBound.apply(this, arguments)
}
* findWithUpperBound () {
yield* this.flush()
return yield* super.findWithUpperBound.apply(this, arguments)
}
* findNext () {
yield* this.flush()
return yield* super.findNext.apply(this, arguments)
}
* findPrev () {
yield* this.flush()
return yield* super.findPrev.apply(this, arguments)
}
* iterate () {
yield* this.flush()
yield* super.iterate.apply(this, arguments)
}
* flush () {
for (var i = 0; i < this.writeBuffer.length; i++) {
var write = this.writeBuffer[i]
if (write.id[0] !== null) {
yield* super.put(write)
this.writeBuffer[i] = {
id: [null, null]
}
}
}
}
}
return SmallLookupBuffer
}
Y.utils.createSmallLookupBuffer = createSmallLookupBuffer
}