Karl Seguin
Associé Gérant at Antidote restaurant
France
Summary
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RockstarKarl Seguin is a pragmatic back-end engineer and entrepreneur with 12 years of experience who currently runs a restaurant business in France while continuing to contribute to high-performance open-source projects. He has hands-on expertise in systems-level programming and Go, with notable contributions to the Crystal language and the widely used pgx PostgreSQL driver, where he focused on performance, memory efficiency, and robustness. Karl also created and evolved ccache, a high-concurrency LRU cache for Go, adding reference counting and usage-tracking features that improve behavior for long-lived objects. His profile combines production-grade engineering discipline with product-minded thinking and operational experience from running a venue, making him comfortable across code, performance optimization, and real-world service delivery. An attention to detail and testing shows through his targeted bug fixes, API enhancements, and added documentation in complex codebases.
12 years of coding experience
Github Skills (16)
testing10
compiler10
caching10
programming-language10
compiler-compiler10
go10
database-driver10
postgresql10
crystal-lang10
performance-optimization10
concurrency10
regex9
arrayobject9
algorithms9
data-structures8
Programming languages (26)
Github contributions (5)
karlseguin/ccache
Feb 2014 - Jan 2023
A golang LRU Cache for high concurrency
Role in this project:
Back-end Developer
Back-end DeveloperContributions:16 releases, 6 reviews, 93 commits in 8 years 11 months
Contributions summary:Karl significantly enhanced the functionality of a Go-based LRU cache. Their work included implementing reference counting to improve the LRU algorithm's efficiency with long-lived objects, such as those referenced by other cached objects. They introduced a `TrackingGet` feature to track item usage, and enhanced test coverage to ensure the cache correctly handled expiring items. The code changes include modifications to `cache.go`, `bucket.go`, `item.go` and addition of specific test cases to `cache_test.go` and `bucket_test.go` to validate the changes.
concurrencygolanglru
jackc/pgx
Nov 2014 - Dec 2014
PostgreSQL driver and toolkit for Go
Role in this project:Back-end Developer
Back-end DeveloperContributions:10 commits in 1 month
Contributions summary:Karl primarily focused on improving the `pgx` Go library, a PostgreSQL driver. Their contributions include performance optimizations, such as using `LastIndex` instead of `Split` and reducing memory allocation through the use of a default logger instance. They also added support for new data types and improved the codebase by fixing bugs and enhancing array handling capabilities.
drivergopostgresql
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