Pinterest的广告投放平台是公司最关键的系统之一，负责每年超过30亿美元的收入。为了解决多年的技术债务并为未来的业务目标奠定基础，广告基础设施团队重新设计和重写了该系统。他们设计了一个复杂的软件系统，采用代码组织和团队变更管理等措施，以确保易于扩展、关注点分离、安全设计和开发速度。通过使用内部图执行框架Apex和创新的数据模型，在迁移过程中保证了安全执行。重写后的AdMixer服务已在生产环境稳定运行，实现了产品创新的加速和大团队的安全开发，开发人员满意度得到大幅提升，还实现了基础设施成本的降低。详细设计和迁移过程请参考博文的第二部分。

Pinterest通过监控和调查实时指标来检测和解决Pinner等待时间和核心Web Vital指标的退化问题。他们发现了2023年一些回归问题的根本原因，即对服务器渲染过程进行更改。为了更好地理解网络请求的开始和结束时间，他们引入了网络拥塞时间。这些实时指标帮助他们分析了不同流式传输处理方式对性能的影响，并发现了一些回归问题的关键原因，例如LCP图像的预加载请求延迟、脚本请求开始时间早于LCP预加载请求完成时间等。通过更新日志标记实验和实验处理，他们可以比较实时子指标，进一步提高调查的效率和成功率。这些实时监控图表对于捕捉在生产环境中发布的回归问题非常有帮助。

Alberto Ordonez Pereira | Senior Staff Software Engineer; Lianghong Xu | Senior Manager, Engineering;

Michelle Vu | Web Performance Engineer

Pinterest发布了一份关于非参与度信号的“领域指南”，旨在帮助在线平台更好地平衡用户参与度与内容质量，并实现用户需求的多样化。该指南提供了对于非参与度信号的应用和决策指导，特别是在调整情绪健康、保护用户权益等方面具有实际可行性。它强调了优化用户参与度对于长期用户留存的重要性，并指出通过使用质量指标和调查反馈等非参与度信号可以进一步提高用户留存率。此外，指南还提到通过使用生成人工智能来扩展内容质量信号的可能性，以及各个平台可以根据指南对自身进行分析和改进的方法。如果您有兴趣加入这项工作，可以了解更多信息并签署“Inspired Internet Pledge”。

Pinterest开发了名为Text-to-SQL的功能，使用大型语言模型（LLM）将问题转化为SQL代码，帮助数据用户。该功能包括表格摘要生成和查询摘要生成。未来的发展方向包括进一步改进NLP表格搜索，增加元数据等。此外，还有一些潜在的改进点，如定期更新向量索引、优化相似性搜索和评分策略、实施查询验证和收集用户反馈。此外，应该创建更真实的基准测试，包括大量非规范化表格和表格搜索。

Adopted by Pinterest multiple user facing surfaces, Ads, and Board.

Goku is a time series database used by Pinterest for monitoring and alerting services. It offers pre-aggregation as an optimization technique for reducing query latency and cardinality. Users can enable pre-aggregation for metrics experiencing high latency or hitting cardinality limits. The Goku team provides users with tag combination distribution for the metric, allowing them to choose the tags they want to preserve in the pre-aggregated time series. After consuming data points from Kafka, the Goku Short Term host checks if the time series qualifies for pre-aggregation. If it does, the data is entered into an in-memory data structure that records various aggregations. Additionally, 5 aggregated data points are emitted for the time series. Goku Root handles query requests and modifies the metric name to query the right time series. The success story mentions a metric with high cardinality that achieved lower latencies after enabling pre-aggregation. Goku has onboarded over 50 use cases for pre-aggregation.

Yulin Lei | Senior Machine Learning Engineer; Kaili Zhang | Staff Machine Learning Engineer; Sharare Zahtabian | Machine Learning Engineer…

Several years ago, Pinterest had a short incident due to oversights in the policy delivery engine. This engine is the technology that ensures a policy document written by a developer and checked into source control is fully delivered to the production system evaluating that policy, similar to OPAL. This incident began a multi-year journey for our team to rethink policy delivery and migrate hundreds of policies to a new distribution model. We shared details about our former policy delivery system in a conference talk from Kubecon 2019.

At a high level, there are three important architectural decisions we’d like to bring attention to for this story.

At Pinterest, our mission is to bring everyone the inspiration to create a life they love. People often come to Pinterest when they are considering what to do or buy next. Understanding this evolving user journey while balancing across multiple objectives is crucial to bring the best experience to Pinterest users and is supported by multiple recommendation models, with each providing real-time inference with an overall latency of 200–300 milliseconds. In particular, our machine learning powered ads ranking systems are trying to understand users’ engagement and conversion intent and promote the right ads to the right user at the right time. Our engineers are constantly discovering new algorithms and new signals to improve the performance of our machine learning models. A typical development cycle involves offline model training to realize offline model metric gains and then online A/B experiments to quantify online metric movements. However, it is not uncommon that offline metric gains do not translate into online business metric wins. In this blog, we will focus on some online and offline discrepancies and development cycle learnings we have observed in Pinterest ads conversion models, as well as some of the key platform investments Pinterest has made to minimize such discrepancies.

A Journey from GBDT to Multi-Task Ensemble DNN.

Rockstorewidecolumn 是一个大规模用户序列项目，用于存储用户事件数据。该项目已在Pinterest公司使用了两年多，并得到了广泛应用。它能够处理每秒数百万次请求，存储了PB级数据。用户可以根据用户ID、事件类型和事件数量进行查询，并返回每个事件类型的最新N个事件。该项目的成功应用提高了用户参与度。

Better performance, lower cost and less code complexity.

Goku是Pinterest的内部时间序列数据库，用于监控和设置警报。他们改变了数据写入方式和摄取模型，采用基于拉取的、分片感知的摄取模型，并引入了Goku side Kafka。他们还使用本地磁盘和S3替代了EFS作为持久化数据和备份。这些改变使得GokuS的恢复时间从90-120分钟缩短到不到40分钟，提供了高效的查询路由。GokuL利用RocksDB进行时间序列数据存储，使用分层存储的方式，将较小和较新的SST文件在低层进行压缩，存储为较大和较旧的SST文件在高层。GokuL集群存储并提供超过一天的旧数据，这些数据的保留时间为1年。具体的数据分层策略和存储集群信息可以在GokuL博客和成本降低博客中找到。

At Pinterest, data is ingested and transported at petabyte scale every day, bringing inspiration for our users to create a life they love. A central component of data ingestion infrastructure at Pinterest is our PubSub stack, and the Logging Platform team currently runs deployments of Apache Kafka and MemQ. Over the years, operational experience has taught us that our customers and business would greatly benefit from a unified PubSub interface that the platform team owns and maintains, so that application developers can focus on application logic instead of spending precious hours debugging client-server connectivity issues. Value-add features on top of the native clients can also help us achieve more ambitious goals for dev velocity, scalability, and stability. For these reasons, and others detailed in our original PubSub Client blog post, our team has decided to invest in building, productionalizing, and most recently open-sourcing PubSub Client (PSC).

In the 1.5 years since our previous blog post, PSC has been battle-tested at large scale in Pinterest with notably positive feedback and results. From dev velocity and service stability improvements to seamless migrations from native client to PSC, we would like to share some of our findings from running a unified PubSub client library in production.