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From: Mike Hearn <mike@plan99.net>
To: Gavin Andresen <gavinandresen@gmail.com>
Cc: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] LevelDB benchmarking
Date: Tue, 19 Jun 2012 18:06:30 +0200	[thread overview]
Message-ID: <CANEZrP08NrCJM2gxNitXrLjuY6AusNULvkcheN_0MbgFQV_QXw@mail.gmail.com> (raw)
In-Reply-To: <CABsx9T3pQFqL0xsvRfnixYEATO61qMCCDdLmtqZkbVLW0Vxytg@mail.gmail.com>

> What problem does it solve?

Primarily that block verification and therefore propagation is too
slow because it's very CPU and IO intensive. The CPU work can be
multi-threaded. The IO work, not as much. As Bitcoin grows we need to
scale the nodes. Eventually there may be multi-machine nodes, but for
now we can buy more time by making the existing nodes faster.

I don't see this as a replacement for moving users to SPV clients.
Obviously, otherwise I would not be writing one ;)

> If the problem it will solve is the "too easy to get a DB_RUNRECOVERY
> error" because bdb is fragile when it comes to its environment... then
> LevelDB looks very interesting.

I have no experience with how robust LevelDB is. It has an API call to
try and repair the database and I know from experience that BigTable
is pretty solid. But that doesn't mean LevelDB is.

> If the problem is bdb is creaky and old and has obscure semantics and
> a hard-to-work-with API, then yes, lets switch (I'm easily seduced by
> a pretty API and blazing fast performance).

The code is a lot simpler for sure.

> As long as it compiles and runs on mac/windows/linux that doesn't
> really worry me.

It was refactored out of BigTable and made standalone for usage in
Chrome. Therefore it's as portable as Chrome is. Mac/Windows/Linux
should all work. Solaris, I believe, may need 64 bit binaries to avoid
low FD limits.

> Lack of infrastructure because it is new does worry me; for example,
> could I rework bitcointools to read the LevelDB blockchain?  (are
> there python bindings for LevelDB?)

Yes: http://code.google.com/p/py-leveldb/

First look at the code is here, but it's not ready for a pull req yet,
and I'll force push over it a few times to get it into shape. So don't
branch:

https://github.com/mikehearn/bitcoin/commit/2b601dd4a0093f834084241735d84d84e484f183

It has misc other changes I made whilst profiling, isn't well
commented enough, etc.



  reply	other threads:[~2012-06-19 16:06 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-18 18:41 [Bitcoin-development] LevelDB benchmarking Mike Hearn
     [not found] ` <CAAS2fgTNqUeYy+oEFyQWrfs4Xyb=3NXutvCmLusknF-18JmFQg@mail.gmail.com>
2012-06-19  9:05   ` Mike Hearn
2012-06-19 11:38     ` Pieter Wuille
2012-06-19 15:05     ` Gavin Andresen
2012-06-19 16:06       ` Mike Hearn [this message]
2012-06-19 19:22         ` Stefan Thomas
2012-06-20  9:44           ` Mike Hearn
2012-06-20  9:53             ` Mike Hearn
2012-06-20 11:37             ` Pieter Wuille
2012-06-20 12:41               ` Mike Hearn
2012-06-25 16:32                 ` Mike Hearn
2012-07-21 18:49                   ` Mike Hearn

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