# Phase 4 gate — mongo-lite vs MongoDB 8.3.7, 1g dataset / ~16k docs
# Ratio < 1.0 = mongo-lite faster. Reproduce: bash tests/e2e/compare-run.sh 1g 16k
# This run includes roadmap items 1 (B+tree), 2 (ordered _id index) and
# 3 (block-framed LZ4-compressed log).
# Compare: tests/e2e/results/phase1.txt (pre-tree baseline).

benchmark                                   mongo-lite              mongodb                 ratio
insertOne (sequential) ×200                 0.17 ms                 4.2 ms                  0.0x
bulk insert throughput                      722.1 MB/s              824.1 MB/s              0.9x
docs loaded                                 65,536                  65,536                  1.0x
createIndex({k: 1})                         53.9 ms                 84.8 ms                 0.6x
countDocuments({})                          1.5 ms                  11.5 ms                  0.1x
findOne({_id: <ObjectId>})                  0.57 ms                 0.50 ms                 1.1x
findOne({k: 500}) (indexed)                 0.77 ms                 0.86 ms                 0.9x
find({p: {$gte,$lt}}).count() (scan)        22.5 ms                 14.5 ms                 1.6x
find({}).sort({_id:-1}).limit(20)           2.5 ms                  2.3 ms                  1.1x
find({}, {proj}).limit(1000)                4.1 ms                  4.4 ms                  0.9x
aggregate $group by k                       10.2 ms                 15.4 ms                 0.7x
updateOne({_id}) ×50                        0.13 ms                 0.22 ms                 0.6x
updateMany({k: 7}, {$inc})                  2.4 ms                  5.8 ms                  0.4x
deleteOne({_id}) + insertOne                0.64 ms                 3.9 ms                  0.2x
node client RSS                             160 MB                  154 MB                  1.0x
server RSS                                  1979 MB                 1561 MB
kill -9 reopen                              0.8s                    1.3s
db on disk                                  97MB                    104MB

# Item 3 (block-framed LZ4-compressed log) deltas vs phase3:
#   db on disk   1025 -> 97 MB  (11x smaller; now smaller than MongoDB's
#                 own 104 MB). The log is a file header plus ~256 KiB
#                 blocks; each block holds the existing record framing
#                 (Engine.apply_record unchanged) with the integrity hash
#                 covering the stored bytes, so the decompressor only sees
#                 input already proven intact. Torn tails (short read,
#                 impossible length, or hash mismatch in the final block)
#                 truncate cleanly; hash mismatches elsewhere are
#                 InvalidLog. Raw blocks remain legal (per-block codec
#                 byte) when compression does not help.
#   bulk insert  816 -> 722 MB/s (0.9x of MongoDB): the compression cost,
#                 accepted per the roadmap (LZ4 chosen precisely because
#                 deflate would cap writes below the insert rate).
#   reopen       0.8 s (unchanged; decompression of 97 MB is fast).
#
# Remaining gaps and where they are addressed:
#   server RSS  1.3x  -> Phase 4 (per-document arena -> byte storage)
#   range-scan  1.6x  -> Phase 4 (contiguous byte storage, not the matcher)