Fiona Liao
Senior Software Engineer II at Grafana Labs
London, England, United Kingdom
Summary
🤩
Rockstar🎓
Top SchoolFiona Liao is a Senior Software Engineer with 10 years’ experience designing and operating high-performance, multi-tenant observability systems and large-scale data pipelines. Based in London, she has driven query and ingestion work at Grafana Labs—leading the Query squad—and contributed substantive backend and DevOps improvements to flagship open-source projects including Prometheus and Grafana Mimir. Her work spans parsing and histogram handling to per-tenant overrides and Helm chart changes, reflecting deep expertise in time-series data correctness and production reliability. Earlier at Amazon she led data ingestion and knowledge-graph projects for Alexa, combining large-scale ETL, security reviews and mentoring. Known for pragmatic refactors and targeted benchmarks, she brings both hands-on systems engineering and a tested record of improving observability at scale.
10 years of coding experience
6 years of employment as a software developer
Master of Engineering (MEng), Computing, First-Class Honours, Master of Engineering (MEng), Computing, First-Class Honours at Imperial College LondonHigh School, High School at The Tiffin Girls' School
Chinese, English
Github Skills (29)
timeseries-database10
observability10
expressions10
testing10
configuration-management10
graphite10
carbon-copy10
data-structure10
carbon-lang10
go10
prometheus10
expression10
parsing10
parse10
data-structures10
Programming languages (7)
Github contributions (5)
grafana/mimir
Feb 2023 - Jul 2026
Grafana Mimir provides horizontally scalable, highly available, multi-tenant, long-term storage for Prometheus.
Role in this project:
Back-end & DevOps Engineer
Back-end & DevOps EngineerContributions:57 reviews, 39 PRs, 276 pushes in 3 years 5 months
Contributions summary:Fiona contributed to the backend functionality of Grafana Mimir by implementing per-tenant overrides for query ingesters, enhancing the system's multi-tenancy capabilities. They also worked on Helm chart modifications, specifically removing the graphite-web component from the graphite proxy configuration. Furthermore, the user added support for ingesting out-of-order native histograms. These contributions indicate a focus on system performance, configuration, and data handling within the observability domain.
grafana-mimirmulti-tenantprometheusmetricstsdb
prometheus/prometheus
Apr 2021 - Apr 2021
The Prometheus monitoring system and time series database.
Role in this project:Back-end Developer
Back-end DeveloperContributions:69 reviews, 1 commit, 24 PRs in 1 day
Contributions summary:Fiona significantly contributed to the Prometheus codebase by addressing and fixing critical bugs related to the `memSafeIterator` and WAL (Write Ahead Log) components, specifically focusing on improving time series data handling and iteration. They implemented improvements for the out-of-order samples processing, including refactoring the loading mechanism and adding new benchmarks. The contributions also involve code optimization and implementing features to improve the performance and stability of the Prometheus system. The user also worked on improving histogram handling, fixing associated append errors and counter reset issues.
monitoringprometheustimeseries-databasemetricsalerting
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