The auto-detected query-limit cap was computed from os.freemem() (MemFree),
which excludes reclaimable page cache. On hosts that memory-map large index
files the cache holding those pages dominates RAM, so MemFree collapses to a
sliver and the cap cratered to its floor on perfectly healthy machines,
rejecting legitimate find() calls.
- getAvailableMemory() now prefers /proc/meminfo MemAvailable (counts
reclaimable cache), falling back to os.freemem() off-Linux, then a 2 GB
constant where no OS module is available.
- Auto-detected caps (container + free-memory tiers) are floored at
MIN_AUTO_QUERY_LIMIT (10_000); a transient low reading can never throttle
queries to a near-useless ceiling. Consumer-supplied maxQueryLimit /
reservedQueryMemory bypass the floor — an explicit caller knows their box.
Also scrubs two stale comments referencing the removed cloud storage
adapters and the retired mmap-vector backend: 8.0's native vector provider
persists its own .dkann file via getBinaryBlobPath, so the old rootDirectory
hook does not apply on this line.
Tests: memoryLimits 26/26 (4 new floor regressions), unit 1398/1398,
find-limits + db-mvcc + api-parameter-validation 37/37.
David Snelling
b26d3d42b3