Changes between Initial Version and Version 1 of NifDB

Timestamp:

Feb 23, 2012, 3:59:44 PM (13 years ago)

Author:

manualwiki

Comment:

NifDB created

NifDB

@@ +1 @@
+= Using the NIF database back-end =
+
+Currently, the Mnesia based back-end is the default,
+therefore you have to specify a command line argument if you would like to use the NIF based back-end.
+
+After the system is installed, start !RefactorErl with
+{{{
+#!sh
+
+bin/referl -db nif
+}}}
+
+NIF uses the !RefactorErl data directory to store its data. You can specify it by typing
+{{{
+#!sh
+
+bin/referl -db nif -dir /path/to/your/data/dir
+}}}
+
+If you would like to start several instances of !RefactorErl/NIF,
+you have to choose different node names.
+It is also suggested to set different data directories as well,
+although it is not strictly required.
+{{{
+#!sh
+
+bin/referl -db nif -sname name1 -dir /path/to/your/data/dir1
+bin/referl -db nif -sname name2 -dir /path/to/your/data/dir2
+
+# or
+
+bin/referl -db nif -name name1 -dir /path/to/your/data/dir1
+bin/referl -db nif -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.
+% This operation is always executed after transformations
+% and file operations (e.g. adding or dropping a file).
+ri:backup().
+
+% Make a checkpoint with a commit log message.
+ri:backup(CommitLogMsg).
+
+% Lists all backups.
+ri:ls_backups().
+
+% Undo all changes made since the last backup.
+ri:undo().
+
+% Removes all backups.
+ri:clean().
+}}}
+
+You can also use all [[SemanticQuery|querying]] and [[RefactoringSteps|refactoring functionalities]].
+
+= Comparison with the Mnesia back-end =
+
+While the [[MnesiaDB|Mnesia]] back-end has been under development longer and can be expected to be more stable,
+it is much slower than the 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.