This id one by shifting right slots in a stash bucket of the full segment.
In addition, I added eviction related stats to memory and stats section.
I also updated README with the changes. Finally, I added a flag that allows
to disable http-admin console in dragonfly.
1. Make EngineShardSet to be a process singleton instead of a variable passed everywhere.
2. Implement a heuristic of updating free memory per shard.
3. Make sure that SET command returns OOM when a database reaches its limits.
The heart of this feature is ability to bump up entries that has been searched for.
When we bump up an entry withing a dash-table it's moved out of stash buckets or to lower slot ids
within normal buckets. The entry they replace is moved to the place of bumped-up entries.
The next change will be to implement the actual eviction heuristic that will evict keys from the stash buckets.
This will give stash buckets an addition responsibility for caching mode - they will serve as a probation buffer
that holds low-priority or newly added items.
1. Simplify versioning scheme. This also reduces metadata space and increases table capacity
for same memory reservation by ~%5.
2. Fix snapshotting bugs. Recognize duplicate keys during loading.
3. Introduce DEBUG LOAD command to perform manual loading of files.
1. Reads from external storage support now o_direct mode.
2. Simplify write unloading logic. Make pending buffer a ring buffer with
a predefined capacity.
3. Add more tiered stats to info command
1. Docker build now builds for arm64 as well.
2. Add bind option to specify on which interface the server should listen.
3. Automatically deduce maxmemory setting.
1. External allocator now allocates blocks that are multiples of 8KB and are aligned to 8KB.
This allows to use it with O_DIRECT files. 4KB was enough but since we can group small strings within
a single block anyway, we can increase minimal block sizes.
2. Fix constants dependencies within external allocator. Improve code structure.
3. Limit string offloading to string sizes below 2MB. Currently we do not support external allocations of larger sizes.
Roman Gershman