package index

1.4.1 (2021-07-16)

Fixed

• Proper cleaning of merge file descriptors when aborting a merge (#326)
• Recover from crash of the merge thread. When this happen, the main thread can continue to run and will need to recover from the crash before doing a new merge. This fixes a critical issue which might cause data loss (#339)
• Make sure that no entries can disappear for read-only instances during log_async recovery (#338)

1.4.0 (2021-06-16)

Fixed

• Fixed a crash-consistency bug due to a potential flush of an incomplete entry to disk. Entries are now flushed as complete strings. (#301)
• Attempt to recover from log_async invariant violations during an explicit sync operation, rather than failing immediately. (#329)

Changed

• Release overly defensive warnings occuring when pre-fetching the disk. (#322)
• Optimised the in-memory representation of index handles and intermediate buffers, resulting in a significant reduction in memory use. (#273, #279)
• Benches are now executed 3 times and a new option nb-exec has been added (#292)
• Index.Make now requires an implementation of a monotonic time source. (#321)
• The Index.Make functor now takes a single Platform argument containing all system dependencies (i.e. IO, Clock, Semaphore and Thread). The Platform module holds the necessary types for these modules. (#321, #330)

Added

• Added benchmarks that replay a trace of index operations. (#300)
• Log reporter for the benches

1.3.1 (2021-04-29)

Fixed

• Reduce allocations during merge (#274, #277)
• Protect concurrent syncs with a lock (#309)
• Fixed a performance issue for Index.sync when there is a blocking merge in progress: the log_async file was not cached properly and fully reloaded from disk every time. (#310)
• Release the merge lock if a merge raises an exception (#312)
• Added fsync after Index.clear to signal more quickly to read-only instances than something has changed in the file (#308)

Changed

• Specialise IO.v to create read-only or read-write instances. (#291)
• clear removes the files on disks and opens new ones containing only the header. (#288, #307, #317)

1.3.0 (2021-01-05)

Added

• Added flush_callback parameter to the creation of a store, to register a callback before a flush. This callback can be temporarily disabled by ~no_callback:() to flush. (#189, #216)
• Added Stats.merge_durations to list the duration of the last 10 merges. (#193)
• Added is_merging to detect if a merge is running. (#192)
• New IO.Header.{get,set} functions to read and write the file headers atomically (#175, #204, @icristescu, @CraigFe, @samoht)
• Added a throttle configuration option to select the strategy to use when the cache are full and an async merge is already in progress. The current behavior is the (default) `Block_writes strategy. The new `Overcommit_memory does not block but continue to fill the cache instead. (#209, @samoht)
• Add IO.exists obligation for IO implementations, to be used for lazy creation of IO instances. (#233, @CraigFe)
• Index.close now takes an ~immediately:() argument. When passed, this causes close to terminate any ongoing asynchronous merge operation, rather than waiting for it to finish. (#185, #234)
• Added Index.Checks.cli, which provides offline integrity checking of Index stores. (#236)
• Index.replace now takes a ~overcommit argument to postpone a merge. (#253)
• Index.merge is now part of the public API. (#253)
• Index.try_merge is now part of the public API. try_merge' is a no-op if the number of entries in the write-ahead log is smaller than log_size, otherwise it's merge'. (#253 @samoht)

Changed

• sync has to be called by the read-only instance to synchronise with the files on disk. (#175)
• Caching of Index instances is now explicit: Index.Make requires a cache implementation, and Index.v may be passed a cache to be used for instance sharing. The default behaviour is not to share instances. (#188)

Fixed

• Added values after a clear are found by read-only instances. (#168)
• Fix a race between merge and sync (#203, @samoht, @CraigFe)
• Fix a potential loss of data if a crash occurs at the end of a merge (#232)
• Fix Index.iter to only iterate once over elements persisted on the disk (#260, @samoht, @icristescu)

1.2.1 (2020-06-24)

Added

• Added Index_unix.Syscalls, a module exposing various Unix bindings for interacting with file-systems. (#176)

Fixed

• Fail when Index_unix.IO file version number is not as expected. (#178)
• Fixed creation of an index when an empty data file exists. (#173)

1.2.0 (2020-02-25)

Added

• Added filter, removing bindings depending on a predicate (#165)

Changed

• Parameterise Index.Make over arbitrary mutex and thread implementations (and remove the obligation for IO to provide this functionality). (#160, #161)

1.1.0 (2019-12-21)

Changed

• Improve the cooperativeness of the merge operation, allowing concurrent read operations to share CPU resources with ongoing merges. (#152)
• Improve speed of read operations for read-only instances. (#141)

Removed

• Remove force_merge from Index.S, due to difficulties with guaranteeing sensible semantics to this function under MRSW access patterns. (#147, #150)

1.0.1 (2019-11-29)

Added

• Provide a better CLI interface for the benchmarks (#130, #133)

Fixed

• Fix a segmentation fault when using musl <= 1.1.20 by not allocating 64k-byte buffers on the thread stack (#132)
• Do not call pwrite with len=0 (#131)
• Clear log.mem on close (#135)
• Load log_async on startup (#136)

1.0.0 (2019-11-14)

First stable release.