[#CValidationInterface-TransactionRemovedFromMempool]
= xref:CValidationInterface.adoc[CValidationInterface]::TransactionRemovedFromMempool
:relfileprefix: ../
:mrdocs:

Notifies listeners of a transaction leaving mempool.

== Synopsis

Declared in `<validationinterface.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
virtual
void
TransactionRemovedFromMempool(
    xref:CTransactionRef.adoc[CTransactionRef] const& tx,
    xref:MemPoolRemovalReason.adoc[MemPoolRemovalReason] reason,
    uint64_t mempool_sequence);
----

== Description

This notification fires for transactions that are removed from the mempool for the following reasons:

* EXPIRY (expired from mempool after ‐mempoolexpiry hours)
* SIZELIMIT (removed in size limiting if the mempool exceeds ‐maxmempool megabytes)
* REORG (removed during a reorg)
* CONFLICT (removed because it conflicts with in‐block transaction)
* REPLACED (removed due to RBF replacement)

This does not fire for transactions that are removed from the mempool because they have been included in a block. Any client that is interested in transactions removed from the mempool for inclusion in a block can learn about those transactions from the MempoolTransactionsRemovedForBlock notification.

Transactions that are removed from the mempool because they conflict with a transaction in the new block will have TransactionRemovedFromMempool events fired _before_ the BlockConnected event is fired. If multiple blocks are connected in one step, then the ordering could be:

* TransactionRemovedFromMempool(tx1 from block A)
* TransactionRemovedFromMempool(tx2 from block A)
* TransactionRemovedFromMempool(tx1 from block B)
* TransactionRemovedFromMempool(tx2 from block B)
* BlockConnected(A)
* BlockConnected(B)

Called on a background thread.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *tx*
| The transaction removed from the mempool.
| *reason*
| Why the transaction was removed.
| *mempool_sequence*
| Mempool sequence number at the time of the removal.
|===


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