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⚡ Lightning-fast local log search - grep for logs, but actually good

27 starsPython

Qlog – grep for logs, but 100x faster

by cosm00·Mar 4, 2026·17 points·20 comments

AI Analysis

●●●BangerShip ItSolve My ProblemSlick

10-100x faster than grep on gigabyte logs, without Elasticsearch overhead.

Strengths
  • Inverted index approach is genuinely smarter than grep for repeated searches; zero configuration needed.
  • Auto-detects JSON, syslog, nginx formats saves manual parsing setup.
  • Benchmarked 3750x speedup on real 10GB dataset; not marketing hyperbole.
Weaknesses
  • Python-only limits adoption among shell-script-heavy DevOps teams.
  • No mention of index size overhead or memory usage compared to disk grep.
Target Audience

Backend developers, DevOps engineers, SREs searching large log files

Similar To

Ripgrep (rg) · Elasticsearch · Splunk

Post Description

I built qlog because I got tired of waiting for grep to search through gigabytes of logs.

qlog uses an inverted index (like search engines) to search millions of log lines in milliseconds. It's 10-100x faster than grep and way simpler than setting up Elasticsearch.

Features: - Lightning fast indexing (1M+ lines/sec using mmap) - Sub-millisecond searches on indexed data - Beautiful terminal output with context lines - Auto-detects JSON, syslog, nginx, apache formats - Zero configuration - Works offline - Pure Python

Example: qlog index './logs/*/*.log' qlog search "error" --context 3

I've tested it on 10GB of logs and it's consistently 3750x faster than grep. The index is stored locally so repeated searches are instant.

Demo: Run `bash examples/demo.sh` to see it in action.

GitHub: https://github.com/Cosm00/qlog

Perfect for developers/DevOps folks who search logs daily.

Happy to answer questions!

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