<p>Amiti Uttarwar answered this in this Bitcoin Core PR review club <a href="https://bitcoincore.reviews/18038" rel="nofollow noreferrer">session</a> on the <a href="https://github.com/bitcoin/bitcoin/pull/18038" rel="nofollow noreferrer">PR 18038</a> in April 2020.</p>
<p><strong>Unbroadcast</strong> (introduced in PR 18038) is defined as when the initial broadcast of a transaction hasn't been deemed successful. Every 10-15 minutes a node re-attempts broadcast of unbroadcast transactions.</p>
<p>An initial broadcast is deemed <strong>successful</strong> by the mempool if it receives a single <code>GETDATA</code> request for that transaction (ie a peer requests the data for that transaction). The mempool keeps track of transactions that it initially broadcasts and maintains a set of unbroadcast transactions containing the txids. It doesn't necessarily know the reason for a &quot;failure&quot;. It may be that the transaction was dropped and didn't reach peers or it may be the case that peers weren't interested in that transaction for some reason. Peers are unlikely to already know about the transaction as it was originated by the source of the initial broadcast.</p>

CC BY-SA 4.0
2021-06-24T08:11:19.633Z
2021-06-24T08:20:00.920Z
2021-06-24T08:20:00.920Z
Michael Folkson
<p>What does &quot;unbroadcast&quot; mean? What does it mean for a transaction to be &quot;successfully&quot; broadcast?</p>
<p>These questions were asked in this Bitcoin Core PR <a href="https://bitcoincore.reviews/22261" rel="nofollow noreferrer">review club</a> on <a href="https://github.com/bitcoin/bitcoin/pull/22261" rel="nofollow noreferrer">PR 2261</a> hosted by Gloria Zhao and have been paraphrased.</p>

<bitcoin-core-development><p2p><broadcast>
What does unbroadcast mean? What does it mean for a transaction to be successfully broadcast?
Michael Folkson
# What does unbroadcast mean? What does it mean for a transaction to be successfully broadcast?

(Asked by: username_0 on 2021-06-23)

What does "unbroadcast" mean? What does it mean for a transaction to be "successfully" broadcast?

These questions were asked in this Bitcoin Core PR [review club](https://bitcoincore.reviews/22261) on [PR 2261](https://github.com/bitcoin/bitcoin/pull/22261) hosted by Gloria Zhao and have been paraphrased.

**Tags:** bitcoin-core-development, p2p, broadcast


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## 1 answers

### Answer by username_0 on 2021-06-24. Score: 2 | Accepted answer

Amiti Uttarwar answered this in this Bitcoin Core PR review club [session](https://bitcoincore.reviews/18038) on the [PR 18038](https://github.com/bitcoin/bitcoin/pull/18038) in April 2020.

**Unbroadcast** (introduced in PR 18038) is defined as when the initial broadcast of a transaction hasn't been deemed successful. Every 10-15 minutes a node re-attempts broadcast of unbroadcast transactions.

An initial broadcast is deemed **successful** by the mempool if it receives a single `GETDATA` request for that transaction (ie a peer requests the data for that transaction). The mempool keeps track of transactions that it initially broadcasts and maintains a set of unbroadcast transactions containing the txids. It doesn't necessarily know the reason for a "failure". It may be that the transaction was dropped and didn't reach peers or it may be the case that peers weren't interested in that transaction for some reason. Peers are unlikely to already know about the transaction as it was originated by the source of the initial broadcast.


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