LMDB — juxt/crux-core dev-SNAPSHOT

LMDB

LMDB can be used as the data store for Crux’s query indices, but can also be used as a transaction log and/or document store in single node clusters.

LMDB tends to provide faster queries than RocksDB in exchange for a slower ingest rate.

Project Dependency

In order to use LMDB within Crux, you must first add LMDB as a project dependency:

deps.edn

juxt/crux-lmdb {:mvn/version "{crux_version}-alpha"}

pom.xml

<dependency>
    <groupId>juxt</groupId>
    <artifactId>crux-lmdb</artifactId>
    <version>{crux_version}-alpha</version>
</dependency>

Using LMDB

Replace the implementation of the desired component with crux.lmdb/->kv-store

JSON

{
  "crux/index-store": {
    "kv-store": {
      "crux/module": "crux.lmdb/->kv-store",
      "db-dir": "/tmp/lmdb"
    }
  },

  "crux/document-store": { ... },
  "crux/tx-log": { ... }
}

Clojure

{:crux/index-store {:kv-store {:crux/module 'crux.lmdb/->kv-store
                               :db-dir (io/file "/tmp/lmdb")}}
 :crux/document-store {...}
 :crux/tx-log {...}}

EDN

{:crux/index-store {:kv-store {:crux/module crux.lmdb/->kv-store
                               :db-dir "/tmp/lmdb"}}
 :crux/document-store {...}
 :crux/tx-log {...}}

Parameters

db-dir (required, string/File/Path): path to LMDB data directory
sync? (boolean, default false): sync to disk after every write
env-flags (int): LMDB flags
env-mapsize(int): LMDB map size