Index benchmarking suite


  • 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.

  • 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)


  • 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)


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


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


  • 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)


  • 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)


  • 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)


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


  • 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.