Database handle

Batch operation

User-defined comparator

Compression setting

Options when opening a database

Options for read operations

Snapshot handle

Options for write operations

Run an action with a snapshot of the database.

The snapshot will be released when the action terminates or throws an exception. Note that this function is provided for convenience and does not prevent the Snapshot handle to escape. It will, however, be invalid after this function returns and should not be used anymore.

Open a database

The returned handle will automatically be released when the enclosing runResourceT terminates.

Write a key/value pair

Delete a key/value pair

Perform a batch mutation

Read a value by key

Create a snapshot of the database.

The returned Snapshot will be released automatically when the enclosing runResourceT terminates. It is recommended to use createSnapshot' instead and release the resource manually as soon as possible.

Create a snapshot of the database which can (and should) be released early.

User-defined filter policy

Create a BloomFilter

Properties exposed by LevelDB

Get a DB property

Destroy the given leveldb database.

Repair the given leveldb database.

Inspect the approximate sizes of the different levels

Compact the underlying storage for the given Range. In particular this means discarding deleted and overwritten data as well as rearranging the data to reduce the cost of operations accessing the data.

Return the runtime version of the underlying LevelDB library as a (major, minor) pair.

Iterator handle

Note that an Iterator requires external synchronization if it is shared between multiple threads which mutate it's state. See examples/iterforkio.hs for a simple example of how to do that.

Run an action with an Iterator. The iterator will be closed after the action returns or an error is thrown. Thus, the iterator will not be valid after this function terminates.

Create an Iterator.

The iterator will be released when the enclosing runResourceT terminates. You may consider to use iterOpen' instead and manually release the iterator as soon as it is no longer needed (alternatively, use withIterator).

Note that an Iterator creates a snapshot of the database implicitly, so updates written after the iterator was created are not visible. You may, however, specify an older Snapshot in the ReadOptions.

Create an Iterator which can be released early.

An iterator is either positioned at a key/value pair, or not valid. This function returns true iff the iterator is valid.

Position at the first key in the source that is at or past target. The iterator is valid after this call iff the source contains an entry that comes at or past target.

Position at the first key in the source. The iterator is valid after this call iff the source is not empty.

Position at the last key in the source. The iterator is valid after this call iff the source is not empty.

Moves to the next entry in the source. After this call, iterValid is true iff the iterator was not positioned at the last entry in the source.

If the iterator is not valid, this function does nothing. Note that this is a shortcoming of the C API: an iterPrev might still be possible, but we can't determine if we're at the last or first entry.

Moves to the previous entry in the source. After this call, iterValid is true iff the iterator was not positioned at the first entry in the source.

If the iterator is not valid, this function does nothing. Note that this is a shortcoming of the C API: an iterNext might still be possible, but we can't determine if we're at the last or first entry.

Return the key for the current entry if the iterator is currently positioned at an entry, ie. iterValid.

Return the value for the current entry if the iterator is currently positioned at an entry, ie. iterValid.

Check for errors

Note that this captures somewhat severe errors such as a corrupted database.