[KPhotoAlbum] Startup performance: the final frontier
rlk at alum.mit.edu
Thu Jun 1 02:32:22 CEST 2017
On Tue, 30 May 2017 22:22:11 -0400 (EDT), Robert Krawitz wrote:
> The last big performance problem I have with kpa is startup. It takes
> about 18 seconds to start up, with the 220K photos in my database.
> I intend to kcachegrind this one of these days. It's a somewhat
> painful experience, given how long it takes to start that way. At
> least from the splash screen, it looks like maybe 80% of the time is
> spent in loading the database, the remainder in creating the main
> window (whatever that really means).
> Saving is also problematic, and autosave is very annoying, but not as
> bad as startup.
> I know there was a move afoot a while back to have an SQL database
> rather than an XML file (and XML's pretty unwieldly for this), but
> IIRC nobody ever got it working and eventually it was pulled out.
So, a little research shows me kpa isn't parsing the config file in
the most efficient way:
It's using QDomDocument, which reads the entire file in. That makes
it easy to extract things the way we want, but is less efficient than
using QXmlStreamReader, which is more of a tokenizer that feeds us
It's possible to read the config.xml file quickly; I did so with
xmllint, which took 2 or 3 seconds. It's something that may be worth
Robert Krawitz <rlk at alum.mit.edu>
*** MIT Engineers A Proud Tradition http://mitathletics.com ***
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