# Latency configuration

These Liberator configuration items allow Liberator to add timestamps to objects for the purposes of latency measurement.

Since Liberator is a [Datasource application](../datasource/index.md), you can also set the [DataSource latency chain configuration items](../datasource/datasource-latency-chains-configuration.md).

Also, see [timestamp-field](liberator-object-configuration-part-1.md#timestamp-field) in [Object configuration (part 1)](liberator-object-configuration-part-1.md).

## timestamp-field

`timestamp-field` specifies the name of a field into which Liberator adds a millisecond timestamp to objects for the purposes of latency measurement. The timestamp allows a client application to calculate the time taken for the record represented by the object to be transmitted to it from this Liberator. The Liberator only adds the `timestamp-field`, and the timestamp within it, to objects that don’t already contain a field of that name.

When you want to measure the latency of data propagation through the Caplin Platform, you typically add a timestamp to updates within the component where the update records are first created - usually in the Integration Adapter that’s the source of the data. Defining a `timestamp-field` for the Liberator allows objects that didn’t originate from an Integration Adapter to be time stamped as well.

If you ensure that `timestamp-field` specifies the same field name as that used for the Integration Adapter’s timestamps, Liberator won’t add a second timestamp to objects received from the Integration Adapter, and it won’t overwrite the objects' original timestamps.

This timestamping facility is independent of, the [latency chain timestamps](../datasource/datasource-latency-chains-configuration.md), and it isn’t controlled by the setting of the [latency-chain-enable](../datasource/datasource-latency-chains-configuration.md#latency-chain-enable) configuration item.

This configuration item is overridden by the [timestamp-field](liberator-object-configuration-part-1.md#timestamp-field) option of [add-object](liberator-object-configuration-part-1.md#add-object) for that particular object only.

**Syntax:** `timestamp-field <field-name>`

**Type:** string

**Default value:** no timestamp field is defined so Liberator does not add timestamps to any objects, apart from objects that have been defined by [add-object](liberator-object-configuration-part-1.md#add-object) and have the [timestamp-field](liberator-object-configuration-part-1.md#timestamp-field) _option_ specified.

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**See also:**

* Reference: [Latency chains configuration](../datasource/datasource-latency-chains-configuration.md) in DataSource applications
* How can I... [Record latency in record updates](../datasource/datasource-record-latency-in-record-updates.md)
* How can I... [Monitor latency using the CMC](../cmc/cmc-monitor-latency-using-the-cmc.md)