I think this entire proposal to move away from XML and to an ad-hoc format
is a very bad one.
I've seen many projects use XML for large datasets, and do so very
efficiently. Why not try to improve the existing implementation, rather
than inventing a new format and going through all the unnecessary pain?
The key to XML (or anything) is usually understanding the data flow of the
most important performance-sensitive operations, and then structuring your
implementation around it. If you are concerned about entries files that are
large enough that using an XML DOM is painful, then use one of the streaming
XML implementations, which give you a great deal of control over how the
data is read/written, and when.
Abandoning XML without truly compelling reasons is a very bad idea. And if
performance is so critical, then replace the XML entries file with a
Berkeley DB file (btree), rather than building yet another hacked-up text
format. At least with BDB, there's already a solid implementation.
-- arlie
-----Original Message-----
From: Peter N. Lundblad [mailto:peter@famlundblad.se]
Sent: Friday, April 21, 2006 2:03 AM
To: Peter Samuelson
Cc: dev@subversion.tigris.org
Subject: Re: [PROPOSAL] Drop XML from .svn/entries
Peter Samuelson writes:
>
> [Jonathan Gilbert]
> > Why not add *support* for the new format to the core libraries right >
> away, but not actually create/upgrade repositories at this > > point.
>
> Because maintaining the ability to read *and* write multiple repository
> formats at once is annoying. The normal mode is to read the old format >
but only write the new format.
In general, yes, but it depends on what the format change is. The recent
changes (nonxml-entries and storing wcprops in a single file) require the
odl write support to stay in the code so a new client can run cleanup on an
old WC (we don't try to upgrade a WC that needs cleanup). For
wcpropcaching, the situation is different because the code that runs the
logs doesn't deal with the way properties are stored directly. So, it gets a
little tricky... And everybody who knows how stupid I really am now fears
1.4:-)
Best,
//Peter
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Received on Sun Apr 23 02:51:44 2006