MultiBiSage: A Web-Scale Recommendation System Using Multiple Bipartite Graphs at Pinterest

TL;DR

MultiBiSage is a novel recommendation model at Pinterest that leverages multiple bipartite graphs representing diverse user and content interactions to improve embedding quality and user engagement over existing PinSage models.

Contribution

The paper introduces MultiBiSage, a new data-efficient model that captures multiple bipartite graphs for better node embeddings, extending the PinSage framework to heterogeneous interactions.

Findings

MultiBiSage outperforms PinSage on user engagement metrics.

Utilizes existing Pinterest infrastructure for efficient training.

Models multiple bipartite graphs to capture diverse interactions.

Abstract

Graph Convolutional Networks (GCN) can efficiently integrate graph structure and node features to learn high-quality node embeddings. These embeddings can then be used for several tasks such as recommendation and search. At Pinterest, we have developed and deployed PinSage, a data-efficient GCN that learns pin embeddings from the Pin-Board graph. The Pin-Board graph contains pin and board entities and the graph captures the pin belongs to a board interaction. However, there exist several entities at Pinterest such as users, idea pins, creators, and there exist heterogeneous interactions among these entities such as add-to-cart, follow, long-click. In this work, we show that training deep learning models on graphs that captures these diverse interactions would result in learning higher-quality pin embeddings than training PinSage on only the Pin-Board graph. To that end, we model the diverse entities and their diverse interactions through multiple bipartite graphs and propose a novel data-efficient MultiBiSage model. MultiBiSage can capture the graph structure of multiple bipartite graphs to learn high-quality pin embeddings. We take this pragmatic approach as it allows us to utilize the existing infrastructure developed at Pinterest -- such as Pixie system that can perform optimized random-walks on billion node graphs, along with existing training and deployment workflows. We train MultiBiSage on six bipartite graphs including our Pin-Board graph. Our offline metrics show that MultiBiSage significantly outperforms the deployed latest version of PinSage on multiple user engagement metrics.