Changes between Initial Version and Version 1 of MnesiaDB

Timestamp:

Feb 23, 2012, 3:44:22 PM (14 years ago)

Author:

manualwiki

Comment:

MnesiaDB page created

MnesiaDB

@@ +1 @@
+= Using the Mnesia database back-end =
+
+You do not need additional command line arguments, as this back-end currently the default.
+After the system is installed, you can start RefactorErl with
+{{{
+#!sh
+
+bin/referl
+}}}
+
+Alternatively, you can specify the database manually by typing
+
+{{{
+#!sh
+
+bin/referl -db mnesia
+}}}
+
+Mnesia uses the RefactorErl data directory to store its data. You can specify it by typing
+
+{{{
+#!sh
+
+bin/referl -dir /path/to/your/data/dir
+}}}
+
+Note that if you would like to start several instances of !RefactorErl/Mnesia,
+you currently have to specify different paths for the instances,
+as Mnesia stores the name of the node in the database.
+Obviously, you have to choose different node names as well.
+
+{{{
+#!sh
+
+bin/referl -sname name1 -dir /path/to/your/data/dir1
+bin/referl -sname name2 -dir /path/to/your/data/dir2
+
+# or
+
+bin/referl -name name1 -dir /path/to/your/data/dir1
+bin/referl -name name2 -dir /path/to/your/data/dir2
+}}}
+
+After the system is started, the following operations work on the full database.
+
+{{{
+% Clear the whole database.
+ri:reset().
+
+% Make a checkpoint.
+ri:backup().
+
+% Undo all changes made since the last backup.
+ri:undo().
+}}}
+
+You can also use all [[SemanticQuery|querying]] and [[RefactoringSteps|refactoring functionalities]].
+
+= Comparison with the NIF back-end =
+
+Note that while the Mnesia back-end has been under development longer and can be expected to be more stable,
+it is much slower than the [[NifDB|NIF based back-end]];
+you can expect about an order of magnitude of speed-up.
+Also, the NIF back-end may require less storage.
+As an indication, loading ejabberd-2.1.8 (6.6 MB on disk) takes '''18323 sec''' and '''566 MB''' of RAM and '''66 MB''' of disk space, while the NIF back-end on the same machine takes '''458 sec''' and '''556 MB''' of RAM and '''52 MB''' of disk space.