[kepler-dev] [Bug 5429] improve default provenance store performance

[bugzilla-daemon at ecoinformatics.org]

http://bugzilla.ecoinformatics.org/show_bug.cgi?id=5429

--- Comment #3 from Derik Barseghian <barseghian at nceas.ucsb.edu> 2011-07-06 17:25:25 PDT ---
Did more research yesterday and found some changes to hsqldb post 1.8 that
sound valuable wrt our shutdown performance issue w/ our large database where
the entire 

Found this change comment somewhere:
----------------
New features for incremental backup of the .data file allow speedy handling of
huge databases up to 16GB.

and this:
----------------
22 Feb 2011 - SVN 4096 - 2.1.0 rc4
-- changes to avoid creation of new .data files at checkpoint and allow
incremental enlargement of this file

and 2.0 has this new setting:
----------------
SET FILES BACKUP INCREMENT

set files backup increment statement

<set database backup increment statement> ::= SET FILES BACKUP INCREMENT { TRUE
| FALSE }

Older versions of HSQLDB perform a backup of the .data file before its contents
are modified and the whole .data file is saved in a compressed form when a
CHECKPOINT or SHUTDOWN is performed. This takes a long time when the size of
the database exceeds 100 MB or so (on an average 2010 computer, you can expect
a backup speed of 20MB / s or more).

The alternative is backup in increments, just before some part of the .data
file is modified. In this this mode, no backup is performed at CHECKPIONT or
SHUTDOWN. This mode is prefered for large databases which are opened and closed
frequently.

The default mode is TRUE. If the old method of backup is prefered, the mode can
be set FALSE.

Only a user with the DBA role can execute this statement.

http://hsqldb.sourceforge.net/doc/2.0/guide/deployment-chapt.html

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