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Chapter 6: The Write Stuff: Buffering and Flushing

Understand how search engines handle concurrent writes, memory management, and durability.

Chapter Overview​

The write path is where data enters the search engine and becomes searchable. This chapter covers the journey from document submission through memory buffers, serialization, and eventual persistence to disk, along with the threading models that make high-throughput writes possible.

Understanding the write path is essential for tuning indexing throughput, managing memory pressure, and ensuring data durability.

6.1 Memory and Serialization​

6.1.1 Document-to-segment layout

6.1.2 Single-instruction multiple-data (SIMD) optimizations

6.1.3 Memory mapping vs. traditional file I/O

6.2 Buffers and Flushing Strategies​

6.2.1 Refreshing vs. flushing

6.2.2 Commits, crash recovery, and snapshot durability

6.2.3 Write amplification and merges

6.3 Concurrency and Threading​

6.3.1 Multithreading patterns

6.3.2 Deadlocks, contention, and traps

6.3.3 Async flush, write coalescing, and backpressure

Examples​

Examples coming soon.

Code examples for this chapter will demonstrate buffer tuning, flush strategies, and concurrent write patterns with Lucenia.