Add opt-in zstd page compression to reduce database size#1159
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Add opt-in zstd page compression to reduce database size#1159tjungblu wants to merge 1 commit intoetcd-io:mainfrom
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Introduce a `Compression` option on DB/Options that enables transparent zstd compression of leaf and branch page data. Compression happens at node spill time—before page allocation—so fewer pages are allocated for compressible data. Decompression is transparent on read via a per-transaction cache using sync.Map for concurrent reader safety. Key changes: - New orthogonal CompressedPageFlag (0x20) on page headers; type checks changed from == to bitwise & so the flag coexists with page types - CompressInodes serializes and compresses node data, only used when it reduces the page count - Split threshold increased 4x when compression is enabled so nodes accumulate enough data for meaningful compression - DecompressPage preserves on-disk overflow for correct freelist accounting This was largely written by Claude Opus. Signed-off-by: Thomas Jungblut <tjungblu@redhat.com>
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Introduce a
Compressionoption on DB/Options that enables transparent zstd compression of leaf and branch page data. Compression happens at node spill time—before page allocation—so fewer pages are allocated for compressible data. Decompression is transparent on read via a per-transaction cache using sync.Map for concurrent reader safety.Key changes:
This was largely written by Claude Opus.
Benchmark results and comparison to snappy and without compression can be found here: #1149 (comment)