Database Index Optimization
A deep tuning pass on a write-heavy engine — reading query plans by hand and rebuilding indexes until the tail latency collapsed.
Project Overview
A write-heavy Postgres engine was missing its latency budget under load. We read the query plans by hand, replaced bloated indexes with partial and covering ones, and moved read spikes onto a Redis cache so they no longer competed with writes. Tail latency is already down sharply, with further tuning in progress.
System Features
Plan analysis: EXPLAIN output is parsed to flag sequential scans on hot paths.
Index rebuilds: Partial and covering indexes replace bloated B-trees on the busiest tables.
Cache offload: Redis absorbs read spikes that would otherwise thrash the write path.
SYS_SPECS
- Engine:
- PostgreSQL
- Cache:
- Redis
- Language:
- SQL
- Workload:
- Write-Heavy
ARC_MAP
Challenges & Solutions
# Threat: Write Amplification
Every new index sped reads but taxed the write path, and this table was overwhelmingly write-heavy.
# Remedy: Selective Indexing
Partial indexes cover only the queried subset, cutting write overhead while keeping reads fast. (Tuning ongoing.)