SQlite Session Extension

[ShaunR]

A new feature called the "Session Extension" has just been rolled into the trunk of latest release of SQLite (3.13.0).

From the authors:

Quote

The session extension provide a mechanism for recording changes to some or all of the rowid tables in an SQLite database, and packaging those changes into a "changeset" or "patchset" file that can later be used to apply the same set of changes to another database with the same schema and compatible starting data. A "changeset" may also be inverted and used to "undo" a session.

In a nutshell you can "diff" a database and produce a patchfile of the changes (and the reverse).

Now. Most are probably thinking source code control at this point which isn't very interesting in terms of LabVIEW. However. There is another use case - synchronizing remote acquisition databases.

Previously we could have a SQLite database to store acquired data in, say, a cRIO or PXI chassis. Periodically we would want to back up or synchronize another database either for back up, offline exploitation or the file was becoming too large to store.. This meant making a backup copy locally and then sending the entire database file to the recipient. That could take a long time, was fraught with problems of disconnection and there may have not been enough space to create a copy.

With this new feature we should be able to overcome or at least alleviate these issues and effectively implement "restore points" and "staged updates" for remote databases as well as bandwidth reduction while synchronising and configuring.

For example. We may store configuration information, amongst other things, in the database and only want to update that section. We may only want the last 24 hours of data sent back for exploitation. We may only want error or waveform meta information....and so on.

I'm looking forward to playing with this feature over the next few weeks. so if you have suggestions for another use-case, then I would like to hear it.

Edited June 21, 2016 by ShaunR