74 lines
2.4 KiB
TypeScript
74 lines
2.4 KiB
TypeScript
import { findClosestSnapshot, getLatestSnapshot, hasAtLeast2Snapshots } from "db/snapshotSchedule";
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import { truncate } from "utils/truncate";
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import { closetMilestone } from "./exec/snapshotTick";
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import { HOUR, MINUTE } from "@core/lib";
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import type { Psql } from "@core/db/psql.d";
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import { updateETA } from "db/eta";
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const log = (value: number, base: number = 10) => Math.log(value) / Math.log(base);
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const getFactor = (x: number) => {
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const a = 1.054;
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const b = 4.5;
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const c = 100;
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const u = 0.601;
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const g = 455;
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if (x > g) {
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return log(b / log(x + 1), a);
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} else {
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return log(b / log(x + c), a) + u;
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}
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};
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/*
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* Returns the minimum ETA in hours for the next snapshot
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* @param client - Postgres client
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* @param aid - aid of the video
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* @returns ETA in hours
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*/
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export const getAdjustedShortTermETA = async (sql: Psql, aid: number) => {
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const latestSnapshot = await getLatestSnapshot(sql, aid);
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// Immediately dispatch a snapshot if there is no snapshot yet
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if (!latestSnapshot) return 0;
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const snapshotsEnough = await hasAtLeast2Snapshots(sql, aid);
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if (!snapshotsEnough) return 0;
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const currentTimestamp = new Date().getTime();
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const timeIntervals = [3 * MINUTE, 20 * MINUTE, HOUR, 3 * HOUR, 6 * HOUR, 72 * HOUR];
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const originalWeight = [3, 5, 3, 2, 2, 3];
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const weight = originalWeight.map((x) => x / originalWeight.reduce((a, b) => a + b, 0));
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const DELTA = 0.00001;
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let minETAHours = Infinity;
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let avgSpeed = 0;
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const target = closetMilestone(latestSnapshot.views);
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const viewsToIncrease = target - latestSnapshot.views;
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const factor = truncate(getFactor(viewsToIncrease), 4.5, 100);
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for (const timeInterval of timeIntervals) {
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const date = new Date(currentTimestamp - timeInterval);
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const snapshot = await findClosestSnapshot(sql, aid, date);
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if (!snapshot) continue;
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const hoursDiff = (latestSnapshot.created_at - snapshot.created_at) / HOUR;
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const viewsDiff = latestSnapshot.views - snapshot.views;
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if (viewsDiff <= 0) continue;
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const speed = viewsDiff / (hoursDiff + DELTA);
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avgSpeed += speed * weight[timeIntervals.indexOf(timeInterval)];
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const eta = viewsToIncrease / (speed + DELTA);
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const adjustedETA = eta / factor;
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if (adjustedETA < minETAHours) {
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minETAHours = adjustedETA;
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}
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}
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if (isNaN(minETAHours)) {
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minETAHours = Infinity;
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}
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const avgETAHours = viewsToIncrease / (avgSpeed + DELTA);
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await updateETA(sql, aid, avgETAHours, avgSpeed, latestSnapshot.views);
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return minETAHours;
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};
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