WiredTiger History Store & Tombstone Reclamation (MVCC Bloat)

WiredTiger's internal MVCC version repository and tombstone markers tracking deleted documents, dictating storage bloat and compaction needs.

Internal Architecture Breakdown

WiredTiger leverages a dedicated History Store to preserve previous document versions for active read transactions and snapshot reads. Deleted documents receive tombstone records.

Stalled transactions hold open older read timestamps, preventing WiredTiger from pruning tombstones and inflating disk storage and index scan latency across queries.

Production Inspection Queries

MongoDB

db.serverStatus().wiredTiger['history-store'];
db.collection.stats().wiredTiger['block-manager'];

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