This project provides erlang bindings to a LevelDB datastore heavily optimised for Riak workloads. See the Basho leveldb wiki for a breakdown of the optimisations.
No further work on optimising the underlying store is currently being undertaken, only minimal fixes necessary for platform compatability.
As an alternative, elrang bindings to RocksDB can be found as part of the BarrellDB project. For Riak-like workloads, especially with large objects, the pure-Erlang Leveled store is also available.
The interface that most clients of eleveldb should use when iterating over a set of records stored in leveldb is fold, since this fits nicely with the Erlang way of doing things.
For those who need more control over the process of iterating over records, you can use direct iterator actions. Use them with great care.
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seek: Move iterator to a new position.
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next: Move forward one position and return the value; do nothing else.
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prev: Move backward one position and return the value; do nothing else.
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prefetch: Perform a
nextaction and then start a parallel call for the subsequentnextwhile Erlang processes the currentnext. The subsequentprefetchmay return immediately with the value already retrieved. -
prefetch_stop: Stop a sequence of
prefetchcalls. If there is a parallelprefetchpending, cancel it, since we are about to move the pointer.
Either use prefetch/prefetch_stop or next/prev. Do not intermix prefetch and next/prev. You must prefetch_stop after one or more prefetch operations before using any of the other operations (seek, next, prev).