mirror of
https://github.com/brianc/node-postgres.git
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07988f985a
Move from 3 loops (prepareValue, check for buffers, write param types, write param values) to a single loop. This speeds up the insert benchmark by around 100 queries per second. Performance improvement depends on number of parameters being bound.
86 lines
2.4 KiB
TypeScript
86 lines
2.4 KiB
TypeScript
//binary data writer tuned for encoding binary specific to the postgres binary protocol
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export class Writer {
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private buffer: Buffer
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private offset: number = 5
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private headerPosition: number = 0
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constructor(private size = 256) {
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this.buffer = Buffer.allocUnsafe(size)
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}
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private ensure(size: number): void {
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var remaining = this.buffer.length - this.offset
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if (remaining < size) {
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var oldBuffer = this.buffer
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// exponential growth factor of around ~ 1.5
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// https://stackoverflow.com/questions/2269063/buffer-growth-strategy
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var newSize = oldBuffer.length + (oldBuffer.length >> 1) + size
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this.buffer = Buffer.allocUnsafe(newSize)
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oldBuffer.copy(this.buffer)
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}
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}
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public addInt32(num: number): Writer {
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this.ensure(4)
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this.buffer[this.offset++] = (num >>> 24) & 0xff
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this.buffer[this.offset++] = (num >>> 16) & 0xff
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this.buffer[this.offset++] = (num >>> 8) & 0xff
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this.buffer[this.offset++] = (num >>> 0) & 0xff
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return this
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}
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public addInt16(num: number): Writer {
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this.ensure(2)
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this.buffer[this.offset++] = (num >>> 8) & 0xff
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this.buffer[this.offset++] = (num >>> 0) & 0xff
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return this
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}
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public addCString(string: string): Writer {
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if (!string) {
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this.ensure(1)
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} else {
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var len = Buffer.byteLength(string)
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this.ensure(len + 1) // +1 for null terminator
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this.buffer.write(string, this.offset, 'utf-8')
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this.offset += len
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}
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this.buffer[this.offset++] = 0 // null terminator
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return this
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}
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public addString(string: string = ''): Writer {
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var len = Buffer.byteLength(string)
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this.ensure(len)
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this.buffer.write(string, this.offset)
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this.offset += len
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return this
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}
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public add(otherBuffer: Buffer): Writer {
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this.ensure(otherBuffer.length)
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otherBuffer.copy(this.buffer, this.offset)
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this.offset += otherBuffer.length
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return this
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}
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private join(code?: number): Buffer {
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if (code) {
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this.buffer[this.headerPosition] = code
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//length is everything in this packet minus the code
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const length = this.offset - (this.headerPosition + 1)
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this.buffer.writeInt32BE(length, this.headerPosition + 1)
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}
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return this.buffer.slice(code ? 0 : 5, this.offset)
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}
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public flush(code?: number): Buffer {
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var result = this.join(code)
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this.offset = 5
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this.headerPosition = 0
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this.buffer = Buffer.allocUnsafe(this.size)
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return result
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}
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}
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