[TYPO3-50-general] PHPCR Performance

Martin Poelstra martin at beryllium.net
Fri Jun 22 19:17:32 CEST 2007


Hi Sebastian,

> My current thoughts and ideas are at
> http://www.5-0.dev.typo3.org/trac/TYPO3/wiki/TYPO3CRPerformance - I am
> very curious about your comments!

You actually touched most of the problems one could encounter with this 
scheme quite nicely, so I don't have much to add here :)

For what it's worth, I think you shouldn't concentrate tooooo hard on the 
performance issues of this thing. Trying to put an XML tree in a relational 
database is hard, and according to documents like [1] major modifications 
have been done to (the relational database) MonetDB to make it work fast.
They talk about logical pages, with a separate table for storing the 
pageoffsets, delta-tables for storing the required changes to the records, 
staircase-joins etc. Some of these issues can be resolved by introducing 
extra tables and slightly different (but much slower) queries, but some 
things (like the delta-tables) cannot be implemented in 'normal SQL'.
Especially those delta-tables are necessary to be able to have updates to 
the database while simultaneously being able to read (and write) in other 
requests.

As the latter is probably not really 'fixable' using integer keys, the 
database will be slower anyway. I therefore think, that the 
variable-length-key scheme is the best, if it is possible to implement it, 
as it will not require much maintenance. If that doesn't work, then please 
just use the integer spacing-variant, and if people want real performance 
they just have to use a real solution ;)

Grtz,
Martin

[1] http://pathfinder-xquery.org/files/updating-pre-post.pdf 




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