diff --git a/docs/apm/agent-configuration.asciidoc b/docs/apm/agent-configuration.asciidoc index 2c408a5cc1e7e..4d2ae5d01688c 100644 --- a/docs/apm/agent-configuration.asciidoc +++ b/docs/apm/agent-configuration.asciidoc @@ -43,3 +43,8 @@ Adjusting the sampling rate controls what percent of requests are traced. `1.0` means _all_ requests are traced. If you set the `TRANSACTION_SAMPLE_RATE` to a value below `1.0`, the agent will randomly sample only a subset of transactions. Unsampled transactions only record the name of the transaction, the overall transaction time, and the result. + +IMPORTANT: In a distributed trace, the sampling decision is propagated by the initializing Agent. +This means if you're using multiple agents, only the originating service's sampling rate will be used. +Be sure to set sensible defaults in _all_ of your agents, especially the +{apm-rum-ref}/configuration.html#transaction-sample-rate[JavaScript RUM Agent].