mhttpd and mlogger have been updated with potentially troublesome changes.
Before using these latest versions, please make a backup of your ODB. This is
svn revisions 4434 (mhttpd.c) and 4435 (mlogger.c).

These new features are now available:
- a "feature complete" implementation of "history in an SQL database". We use
this new code to write history data from the T2K test setup in the TRIUMF M11
beam line to a MySQL database (mlogger) and to make history plots directly from
this database (mhttpd). We still write normal midas history files and we have a
utility to import midas .hst files into an SQL database (utils/mh2sql). The code
is functional, but incomplete. For best SQL database data layout, you should
enable the "per variable history" (but backup your ODB before you do this!). All
are welcome to try it, kick the tires, report any problems. Documentation TBW.
- experimental implementation of "ODBRpc" added to the midas javascript library
(ODBSet, ODBGet & co). This permits buttons on midas "custom" web pages to
invoke RPC calls directly into user frontend programs, for example to turn
things on or off. Documentation TBW.
- the mlogger/mhttpd implementation of /History/Tags has proved troublesome and
we are moving away from it. The SQL database history implementation already does
not use it. During the present transition period:
- mlogger and mhttpd will now work without /History/Tags. This implementation
reads history tags directly from the history files themselves. Two downsides to
this: it is slower and tags become non-persistent: if some frontends have not
been running for a while, their variables may vanish from the history panel
editor. To run in this mode, set "/History/DisableTags" to "y". Existing
/History/Tags will be automatically deleted.
- for the above 2 reasons, I still recommend using /History/Tags, but the format
of the tags is now changed to simplify management and reduce odb size. mlogger
will automatically convert the tags to this new format (this is why you should
make a backup of your ODB).
- using old mlogger with new mhttpd is okey: new mhttpd understands both formats
of /History/Tags.
- using old mhttpd with new mlogger is okey: please set ODB
"/History/CreateOldTags" to "y" (type TID_BOOL/"boolean") before starting mlogger.

K.O.