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From: Mike Hearn <mike@plan99.net>
To: Jeremy Spilman <jeremy@taplink.co>
Cc: "bitcoin-development@lists.sourceforge.net"
	<bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] Access to Mempool
Date: Sat, 28 Dec 2013 14:46:05 +0000	[thread overview]
Message-ID: <CANEZrP3t_QYP6giYhJ7H7Zumo0DwaVe=APeY4Kqv=S66g=-QQw@mail.gmail.com> (raw)
In-Reply-To: <op.w8skf2pmyldrnw@laptop-air.hsd1.ca.comcast.net>

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>
> I was reading there are some commands to access a peer's mempool state.
> The purpose being to allow miners to recover faster after a reboot, I
> think?
>

The "mempool" command allows nodes to request the contents of a peers
memory pool, yes.

It is currently used by SPV clients to find transactions that were
broadcast before they were started up (but not yet confirmed).


> Reading peer mempool definitely allows recovering faster after a reboot.
> So does persisting mempool in a database locally.


0.9 has code to save the mempool to disk.


> But what can you learn about a node from its mempool? Basically, are there
> distinguishing
> features in the mempool, or could there be?
>

Er, you mean, distinguishing features beyond the nodes IP address?

The contents of the mempool may vary depending on when the node was started
and what it saw at what times. I guess it's distinguishing in a way, but
not in any important way. Nodes are not intended to be completely
indistinguishable, just indistinguishable enough that it doesn't matter
which you connect to.


> Are there transactions you can receive which go into your own mempool but
> which you don't forward?


I don't think so, unless there are quirks to do with sendrawtransaction
RPCs or strangely crafted wallet spends. Normally if a tx is in the mempool
it will be relayed.


> By the way, are there recommended places to go to compare features
> implemented by different wallet software?
>

I don't know of any such place, but I'm sure people have compiled tables
somewhere.

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      reply	other threads:[~2013-12-28 14:46 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-28  7:29 [Bitcoin-development] Access to Mempool Jeremy Spilman
2013-12-28 14:46 ` Mike Hearn [this message]

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