[ovaistariq]

Problem

cleanupExpiredKeys (every cleaner tick, 1 min by default) and reconcileFromMetadata (startup, then hourly) both started at SeekToFirst and skipped every row that is not under !meta/. The eviction indexes, back-references, compaction and deletion queues live in the same RocksDB, and under LRU there are two index rows per key, so each pass read three rows for every one it could act on. The cost scales with the number of keys, which for TAG's 1 MiB blocks is the cache size in MiB.

Change

• Both loops seek to keys.MetadataPrefix and stop with ValidForPrefix. The per-row prefix check is gone.
• New counter ocache_cleaner_rows_scanned_total{scan="ttl"|"reconcile"} and a scanned field on each pass's completion log, so the walked-row count is visible in production.
• TestCleanerScans_WalkOnlyMetadataRows seeds 1000 rows in keyspaces sorting on both sides of the prefix plus five metadata rows, and asserts the sweep walks exactly 5 and the reconcile exactly 3 (after two expiries are deleted), leaving the other rows intact.

make lint and make test-storage pass.

Closes perfloop cases case_hb73egdr2s and case_456vm3wag5 (the prefix bound is the useful half of the latter; a separate expiry index is not worth its write amplification).

🤖 Generated with Claude Code

https://claude.ai/code/session_01YCoN4Him5ZY4hZovVp37ra

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Note

Medium Risk
Changes core cleaner iteration for TTL deletion and size/eviction-index reconciliation; behavior should be equivalent but mis-scoped prefix iteration could miss rows or skew totals.

Overview
Limits cleaner scans to metadata keys so periodic TTL expiry and startup/hourly size reconciliation no longer walk the full RocksDB and skip eviction indexes, back-references, and queues. Both paths now Seek to keys.MetadataPrefix and iterate with ValidForPrefix, removing per-row IsMetadataKey checks.

Adds ocache_cleaner_rows_scanned_total{scan="ttl"|"reconcile"} and a scanned field on the TTL and reconcile completion logs. TestCleanerScans_WalkOnlyMetadataRows seeds foreign keyspaces and asserts only metadata rows are counted and touched.

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[greptile-apps]

Confidence Score: 5/5

[Medium risk] Optimizes the metadata cleanup sweep to skip non-metadata rows.

The PR appears safe to merge.

Summary

The PR bounds TTL cleanup and size reconciliation to metadata rows, adds scanned-row telemetry, and tests that both scans leave other keyspaces untouched.

_{Reviews (1) · Last reviewed commit: "perf(cleaner): walk only metadata rows i..."}