GH-3416 basic documentation for LDMB Store

bom/pom.xml

@@ -1,7 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0"
-	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
 	<modelVersion>4.0.0</modelVersion>
 	<parent>
 		<groupId>org.eclipse.rdf4j</groupId>
@@ -410,7 +408,6 @@
 				<artifactId>slf4j-simple</artifactId>
 				<version>${slf4j.version}</version>
 			</dependency>
-
 			<!--  LMDB native extensions -->
 			<dependency>
 				<groupId>org.lwjgl</groupId>

core/sail/lmdb/src/main/java/org/eclipse/rdf4j/sail/lmdb/LmdbStore.java

@@ -43,6 +43,8 @@
 /**
  * A SAIL implementation using LMDB for storing and querying its data.
  *
+ * @implNote the LMDB store is is in an experimental state: its existence, signature or behavior may change without
+ *           warning from one release to the next.
  */
 @Experimental
 public class LmdbStore extends AbstractNotifyingSail implements FederatedServiceResolverClient {

core/sail/lmdb/src/main/java/org/eclipse/rdf4j/sail/lmdb/package-info.java

@@ -1,4 +1,7 @@
 /**
  * The LMDB based Store.
+ *
+ * @implNote the LMDB store is in an experimental state: its existence, signature or behavior may change without warning
+ *           from one release to the next.
  */
-package org.eclipse.rdf4j.sail.lmdb;
+package org.eclipse.rdf4j.sail.lmdb;

core/storage/pom.xml

@@ -1,7 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0"
-	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
 	<modelVersion>4.0.0</modelVersion>
 	<parent>
 		<groupId>org.eclipse.rdf4j</groupId>

site/content/documentation/programming/lmdb-store.md

@@ -0,0 +1,68 @@
+---
+title: "The LMDB Store"
+toc: true
+weight: 4
+autonumbering: true
+---
+
+
+{{< tag "New in RDF4J 4.0" >}}
+{{< tag "Experimental" >}}
+
+The RDF4J LMDB Store is a new SAIL database, using the [Symas Lightning
+Memory-Mapped Database](https://www.symas.com/lmdb): a fast embeddable
+key-value database using memory-mapped IO for great performance and stability.
+<!--more-->
+
+
+The LMDB Store can be used in any RDF4J project that requires persistent
+storage that is fast, scalable and reliable.
+
+## Dependencies for the LMDB Store and native extensions
+
+To make use of the LMDB Store, you'll need to include the following Maven dependency:
+
+```xml
+<dependency>
+  <groupId>org.eclipse.rdf4j</groupId>
+  <artifactId>rdf4j-sail-lmdb</artifactId>
+</dependency>
+```
+
+Alternatively you can also rely on the `rdf4j-storage` pom dependency (see (["Which maven artifact?"](/documentation/programming/setup/#which-maven-artifact)), which includes the LMDB Store.
+
+Because the LMDB Store relies on a third party embedded database (LMDB) that is
+not itself a Java library, you'll need two additional runtime dependencies for
+native extensions, provided by [LWJGL](https://lwjgl.org/). These dependencies
+have an OS-specific classifier that is based on the platform OS you wish to run
+on. For example, to run the LMDB Store on a Linux machine, you'll need to
+include the following:
+
+```xml
+<dependency>
+  <groupId>org.lwjgl</groupId>
+  <artifactId>lwjgl</artifactId>
+  <classifier>natives-linux</classifier>
+  <scope>runtime</scope>
+</dependency>
+<dependency>
+  <groupId>org.lwjgl</groupId>
+  <artifactId>lwjgl-lmdb</artifactId>
+  <classifier>natives-linux</classifier>
+  <scope>runtime</scope>
+</dependency>
+```
+
+The required versions of the native extensions are in the [RDF4J Bill Of
+Materials](/documentation/programming/setup/#the-bom-bill-of-materials).
+
+Available extensions for different OS platforms:
+
+| Operating System | native extension classifier |
+|------------------|-----------------------------|
+| Linux            | `natives-linux`             |
+| MS Windows       | `natives-windows`           |
+| Mac OS           | `natives-macos`             |
+| Mac OS (ARM64)   | `natives-macos-arm64`       |
+
+