# Changelog
All notable changes to this project will be documented in this file.

The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
and this project will adhere to [Semantic Versioning](http://semver.org/spec/v2.0.0.html) starting v1.0.0.

## Unreleased

## [0.1.0] - 2021-06-03

[0.1.0]: https://github.com/dgraph-io/ristretto/compare/v0.1.0..v0.0.3
This release contains bug fixes and improvements to Ristretto. It also contains
major updates to the z package. The z package contains types such as Tree (B+
tree), Buffer, Mmap file, etc. All these types are used in Badger and Dgraph to
improve performance and reduce memory requirements.

### Changed
- Make item public. Add a new onReject call for rejected items. (#180)

### Added
- Use z.Buffer backing for B+ tree (#268)
- expose GetTTL function (#270)
- docs(README): Ristretto is production-ready. (#267)
- Add IterateKV (#265)
- feat(super-flags): Add GetPath method in superflags (#258)
- add GetDuration to SuperFlag (#248)
- add Has, GetFloat64, and GetInt64 to SuperFlag (#247)
- move SuperFlag to Ristretto (#246)
- add SuperFlagHelp tool to generate flag help text (#251)
- allow empty defaults in SuperFlag (#254)
- add mmaped b+ tree (#207)
- Add API to allow the MaxCost of an existing cache to be updated. (#200)
- Add OnExit handler which can be used for manual memory management (#183)
- Add life expectancy histogram (#182)
- Add mechanism to wait for items to be processed. (#184)

### Fixed
- change expiration type from int64 to time.Time (#277)
- fix(buffer): make buffer capacity atleast defaultCapacity (#273)
- Fixes for z.PersistentTree (#272)
- Initialize persistent tree correctly (#271)
- use xxhash v2 (#266)
- update comments to correctly reflect counter space usage (#189)
- enable riscv64 builds (#264)
- Switch from log to glog (#263)
- Use Fibonacci for latency numbers
- cache: fix race when clearning a cache (#261)
- Check for keys without values in superflags (#259)
- chore(perf): using tags instead of runtime callers to improve the performance of leak detection (#255)
- fix(Flags): panic on user errors (#256)
- fix SuperFlagHelp newline (#252)
- fix(arm): Fix crashing under ARMv6 due to memory mis-alignment (#239)
- Fix incorrect unit test coverage depiction (#245)
- chore(histogram): adding percentile in histogram (#241)
- fix(windows): use filepath instead of path (#244)
- fix(MmapFile): Close the fd before deleting the file (#242)
- Fixes CGO_ENABLED=0 compilation error (#240)
- fix(build): fix build on non-amd64 architectures (#238)
- fix(b+tree): Do not double the size of btree (#237)
- fix(jemalloc): Fix the stats of jemalloc (#236)
- Don't print stuff, only return strings.
- Bring memclrNoHeapPointers to z (#235)
- increase number of buffers from 32 to 64 in allocator (#234)
- Set minSize to 1MB.
- Opt(btree): Use Go memory instead of mmap files
- Opt(btree): Lightweight stats calculation
- Put padding internally to z.Buffer
- Chore(z): Add SetTmpDir API to set the temp directory (#233)
- Add a BufferFrom
- Bring z.Allocator and z.AllocatorPool back
- Fix(z.Allocator): Make Allocator use Go memory
- Updated ZeroOut to use a simple for loop.  (#231)
- Add concurrency back
- Add a test to check concurrency of Allocator.
- Fix(buffer): Expose padding by z.Buffer's APIs and fix test (#222)
- AllocateSlice should Truncate if the file is not big enough (#226)
- Zero out allocations for structs now that we're reusing Allocators.
- Fix the ristretto substring
- Deal with nil z.AllocatorPool
- Create an AllocatorPool class.
- chore(btree): clean NewTree API (#225)
- fix(MmapFile): Don't error out if fileSize > sz (#224)
- feat(btree): allow option to reset btree and mmaping it to specified file. (#223)
- Use mremap on Linux instead of munmap+mmap (#221)
- Reuse pages in B+ tree (#220)
- fix(allocator): make nil allocator return go byte slice (#217)
- fix(buffer): Make padding internal to z.buffer (#216)
- chore(buffer): add a parent directory field in z.Buffer (#215)
- Make Allocator concurrent
- Fix infinite loop in allocator (#214)
- Add trim func
- Use allocator pool. Turn off freelist.
- Add freelists to Allocator to reuse.
- make DeleteBelow delete values that are less than lo (#211)
- Avoid an unnecessary Load procedure in IncrementOffset.
- Add Stats method in Btree.
- chore(script): fix local test script (#210)
- fix(btree): Increase buffer size if needed. (#209)
- chore(btree): add occupancy ratio, search benchmark and compact bug fix (#208)
- Add licenses, remove prints, and fix a bug in compact
- Add IncrementOffset API for z.buffers (#206)
- Show count when printing histogram (#201)
- Zbuffer: Add LenNoPadding and make padding 8 bytes (#204)
- Allocate Go memory in case allocator is nil.
- Add leak detection via leak build flag and fix a leak during cache.Close.
- Add some APIs for allocator and buffer
- Sync before truncation or close.
- Handle nil MmapFile for Sync.
- Public methods must not panic after Close() (#202)
- Check for RD_ONLY correctly.
- Modify MmapFile APIs
- Add a bunch of APIs around MmapFile
- Move APIs for mmapfile creation over to z package.
- Add ZeroOut func
- Add SliceOffsets
- z: Add TotalSize method on bloom filter (#197)
- Add Msync func
- Buffer: Use 256 GB mmap size instead of MaxInt64 (#198)
- Add a simple test to check next2Pow
- Improve memory performance (#195)
- Have a way to automatically mmap a growing buffer (#196)
- Introduce Mmapped buffers and Merge Sort (#194)
- Add a way to access an allocator via reference.
- Use jemalloc.a to ensure compilation with the Go binary
- Fix up a build issue with ReadMemStats
- Add ReadMemStats function (#193)
- Allocator helps allocate memory to be used by unsafe structs (#192)
- Improve histogram output
- Move Closer from y to z (#191)
- Add histogram.Mean() method (#188)
- Introduce Calloc: Manual Memory Management via jemalloc (#186)

## [0.0.3] - 2020-07-06

[0.0.3]: https://github.com/dgraph-io/ristretto/compare/v0.0.2..v0.0.3

### Changed

### Added

### Fixed

- z: use MemHashString and xxhash.Sum64String ([#153][])
- Check conflict key before updating expiration map. ([#154][])
- Fix race condition in Cache.Clear ([#133][])
- Improve handling of updated items ([#168][])
- Fix droppedSets count while updating the item ([#171][])

## [0.0.2] - 2020-02-24

[0.0.2]: https://github.com/dgraph-io/ristretto/compare/v0.0.1..v0.0.2

### Added

- Sets with TTL. ([#122][])

### Fixed

- Fix the way metrics are handled for deletions. ([#111][])
- Support nil `*Cache` values in `Clear` and `Close`. ([#119][]) 
- Delete item immediately. ([#113][])
- Remove key from policy after TTL eviction. ([#130][])

[#111]: https://github.com/dgraph-io/ristretto/issues/111
[#113]: https://github.com/dgraph-io/ristretto/issues/113
[#119]: https://github.com/dgraph-io/ristretto/issues/119
[#122]: https://github.com/dgraph-io/ristretto/issues/122
[#130]: https://github.com/dgraph-io/ristretto/issues/130

## 0.0.1

First release. Basic cache functionality based on a LFU policy.