Ultraprune merged in mainline

Hello everyone,

I've just merged my "ultraprune" branch into mainline (including Mike's LevelDB work). This is a very significant change, and all testing is certainly welcome. As a result of this, many pull requests probably don't apply cleanly anymore. If you need help rebasing them on the new structure, ask me.

The idea behind ultraprune is to use an ultra-pruned copy (only unspent transaction outputs in a custom compact format) of the block chain for validation (as opposed to a transaction index into the block chain). It still keeps all blocks around for serving them to other nodes, for rescanning, and for reorganisations. As such, it is still a full node. So, despite the name, it does not implement any actual pruning yet, though pruning would be trivial to implement now. This would have profound effects on the network though, so may still need some discussion first.

A small summary of the changes: * Instead of blk000?.dat, we have blocks/blk000??.dat files of max 128 MiB, pre-allocated per 16 MiB * Instead of a Berklely DB blkindex.dat, we have a LevelDB directory blktree/. This only contains a block index, no transaction index. * A new LevelDB directory coins/, which contains data about the current unspent transaction output set. * New files blocks/rev000??.dat contain undo data for blocks (necessary for reorganisation). * More information is kept about blocks and block files, so facilitate pruning in the future, and to prepare for a headers-first mode. * Two new RPC calls are added: gettxout and gettxoutsetinfo.

The most noticeable change should be performance: LevelDB deals much better with slow I/O than BDB does, and the working set size for validation is an order of magnitude smaller. In the longer run, I think it is an evolution towards separation between validation nodes and archive nodes, which is needed in my opinion.

i can happily start testing this this weekend. however i'm not 100% sure how to get a copy. i looked around github, but wasn't sure which was the proper project. could i get a link and a simple "do this, this and this"? thanks.

i feel like a newb. ugh.

Arklan

---------- As long as there is light, the darkness holds no fear. And yet, even in the deepest black, there is life. - Arklan Uth Oslin

I want to leave this world the same way I came into it: backwards and on fire. - Arklan Uth Oslin

On Sat, Oct 20, 2012 at 4:33 PM, Pieter Wuille <pieter.wuille@gmail•com>wrote:

> Hello everyone,
>
> I've just merged my "ultraprune" branch into mainline (including
> Mike's LevelDB work). This is a very significant change, and all
> testing is certainly welcome. As a result of this, many pull requests
> probably don't apply cleanly anymore. If you need help rebasing them
> on the new structure, ask me.
>
> The idea behind ultraprune is to use an ultra-pruned copy (only
> unspent transaction outputs in a custom compact format) of the block
> chain for validation (as opposed to a transaction index into the block
> chain). It still keeps all blocks around for serving them to other
> nodes, for rescanning, and for reorganisations. As such, it is still a
> full node. So, despite the name, it does not implement any actual
> pruning yet, though pruning would be trivial to implement now. This
> would have profound effects on the network though, so may still need
> some discussion first.
>
> A small summary of the changes:
>  * Instead of blk000?.dat, we have blocks/blk000??.dat files of max
> 128 MiB, pre-allocated per 16 MiB
>  * Instead of a Berklely DB blkindex.dat, we have a LevelDB directory
> blktree/. This only contains a block index, no transaction index.
>  * A new LevelDB directory coins/, which contains data about the
> current unspent transaction output set.
>  * New files blocks/rev000??.dat contain undo data for blocks
> (necessary for reorganisation).
>  * More information is kept about blocks and block files, so
> facilitate pruning in the future, and to prepare for a headers-first
> mode.
>  * Two new RPC calls are added: gettxout and gettxoutsetinfo.
>
> The most noticeable change should be performance: LevelDB deals much
> better with slow I/O than BDB does, and the working set size for
> validation is an order of magnitude smaller. In the longer run, I
> think it is an evolution towards separation between validation nodes
> and archive nodes, which is needed in my opinion.
>
> --
> Pieter
>
>
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