> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/server/reference/clientserver-protocol/replication-protocol/heartbeat_log_event.md).

# HEARTBEAT\_LOG\_EVENT

A heartbeat event sent over the network by the master when there are no binlog events, ensuring the replica knows the connection is still active.

This event does not appear in the [binary log](/docs/server/server-management/server-monitoring-logs/binary-log.md). It's only sent over the network by a master to a replica server to let it know that the master is still alive, and is only sent when the master has no binlog events to send to replica servers.

{% hint style="info" %}
This event is never written to the binary log file.
{% endhint %}

## Header

* Timestamp is set to `0`.
* Next position is set to last position.
* Type is set to `HEARTBEAT_EVENT` (`0x1b`).

## Fields

* [string\<EOF>](/docs/server/reference/clientserver-protocol/protocol-data-types.md#fixed-length-bytes) The current master binary log name.

## Example of Transmission (Without CRC32)

```
T 127.0.0.1:8808 -> 127.0.0.1:57157 [AP]
  23 00 00 04 00 00 00 00    00 1b 67 2b 00 00 22 00    '.........g+..&.
  00 00 ed 01 00 00 20 00    66 6f 6f 2d 62 69 6e 2e    ...... .log-bin.
  31 30 30 30 31 33 39                                  1000139
```

## Network Replication protocol, 5 bytes

* packet size \[3] = 23 00 00 => 00 00 23 => 35 (ok byte + event size).
* pkt sequence \[1] = 04.
* `OK` indicator \[1] = 0 (`OK`).

## Heartbeat Event

### **Header**

* Timestamp \[4] = 00 00 00 00 => 0.
* Event Type \[1] = 1b => 27.
* Server\_id \[4] = 67 2b 00 00 => 00 00 2b 67 => 111111.
* Event Size \[4] = 22 00 00 00 => 00 00 00 26 => 34 (header + data).
* Next\_pos \[4] = ed 01 00 00 => 00 00 01 ed => 493.
* Flags \[2] == 20 00 => 00 20 = > 32.

### **Content, String\<EOF>**

* log-bin.1000139.

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{% @marketo/form formId="4316" %}