---
name: "pmdatrace"
section: "1"
platform: "linux"
package: "pcp"
version: "7.2.2-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/pmdatrace"
---

# pmdatrace(1)

application-level transaction performance metrics domain agent

## NAME

**pmdatrace** - application-level transaction performance metrics domain agent

## SYNOPSIS

**$PCP\_PMDAS\_DIR/trace/pmdatrace** \[**-D** *debug*\] \[**-d** *domain*\] \[**-l** *logfile*\] \[**-A** *access*\] \[**-I** *port*\] \[**-M** *username*\] \[**-N** *buckets*\] \[**-T** *period*\] \[**-U** *units*\]

## DESCRIPTION

**pmdatrace** is a Performance Metrics Domain Agent (PMDA) which exports transaction performance metrics from application processes which use the *pcp\_trace* library described in [**pmdatrace**(3)](/pmdatrace/3.md).

A brief description of the **pmdatrace** command line options follows:

- **-d**

  It is absolutely crucial that the performance metrics *domain* number specified here is unique and consistent. That is, *domain* should be different for every PMDA on the one host, and the same *domain* number should be used for the same PMDA on all hosts.

- **-l**

  Location of the log file.  By default, a log file named *trace.log* is written in the current directory of [**pmcd**(1)](/pmcd/1.md) when **pmdatrace** is started, i.e. **$PCP\_LOG\_DIR/pmcd**. If the log file cannot be created or is not writable, output is written to the standard error instead.

- **-A**

  Host-based access control for **pmdatrace**. *access* must be either an allow or deny specification, using either allow:hostspec:maxconns or disallow:hostspec, where \`allow' and \`disallow' are keywords, \`hostspec' is a host specification conforming to the format used by both [**pmcd**(1)](/pmcd/1.md) and [**pmlogger**(1)](/pmlogger/1.md), and \`maxconns' is the maximum number of connections allowed from a given \`hostspec'. Using a maximum connections of zero specifies an unlimited number of connections for the accompanying \`hostspec'.

- **-I**

  Communicate with *pcp\_trace* clients via the given Internet *port*. This can alternatively be specified by setting **$PCP\_TRACE\_PORT** in the environment to some valid port number (use of the **-I** option overrides this). The default port number is 4323.

- **-T**

  *period* defines the aggregation period used to compute the recent averages and extrema. Specified as a time interval using the syntax described in [**PCPIntro**(1)](/PCPIntro/1.md) for the common **-t** PCP argument, e.g. **30 seconds** or **1 min**. The default is 60 seconds.

- **-M**

  User account under which to run the agent. The default is the unprivileged "pcp" account in current versions of PCP, but in older versions the superuser account ("root") was used by default.

- **-N**

  Internally, the aggregation *period* is divided into *bucket* divisions, and the rolling average is recomputed every *period*/*bucket* seconds. For example, the defaults correspond to -T 60 and -N 12, which means the average is recomputed every five seconds for a period covering the prior 60 seconds.

- **-U**

  This option allows the dimension and scale associated with the observation value metric to be configured. *units* is a comma-separated string of six integer values, which are the space dimension, time dimension, count dimension, space scale, time scale, and count scale, respectively. The default dimension and scale is \`\`none'', which is equivalent to presenting \`\`0,0,0,0,0,0'' as the argument to -U. The units associated with a metric are most easily viewed using the -d (metric description) option to [**pminfo**(1)](/pminfo/1.md). The Install script described below steps through this option quite explicitly, so it is recommended that the Install script be used for building up the *units* specification.

Essentially, the exported metrics provide statistics on the time for completion of each transaction, and an average count of transactions completed and watch points passed over a given time *period*.

## INSTALLATION

In order for a host to export the names, help text and values for the Trace performance metrics, do the following as root:

```
# cd $PCP_PMDAS_DIR/trace
# ./Install
```

If you want to undo the installation, do the following as root:

```
# cd $PCP_PMDAS_DIR/trace
# ./Remove
```

**pmdatrace** is launched by [**pmcd**(1)](/pmcd/1.md) and should never be executed directly. The Install and Remove scripts notify [**pmcd**(1)](/pmcd/1.md) when the agent is installed or removed.

## FILES

- **$PCP\_PMCDCONF\_PATH**

  command line options used to launch **pmdatrace**

- **$PCP\_PMDAS\_DIR/trace/help**

  default help text file for the trace metrics

- **$PCP\_DEMOS\_DIR/trace/\***

  example programs which use the *pcp\_trace* library

- **$PCP\_PMDAS\_DIR/trace/Install**

  installation script for the **pmdatrace** agent

- **$PCP\_PMDAS\_DIR/trace/Remove**

  undo installation script for **pmdatrace**

- **$PCP\_LOG\_DIR/pmcd/trace.log**

  default log file for error messages and other information from **pmdatrace**

## PCP ENVIRONMENT

Environment variables with the prefix **PCP\_** are used to parameterize the file and directory names used by PCP. On each installation, the file **/etc/pcp.conf** contains the local values for these variables. The **$PCP\_CONF** variable may be used to specify an alternative configuration file, as described in [**pcp.conf**(5)](/pcp.conf/5.md).

## DEBUGGING OPTIONS

The **-D** or **--debug** option enables the output of additional diagnostics on *stderr* to help triage problems, although the information is sometimes cryptic and primarily intended to provide guidance for developers rather than for end-users. *debug* is a comma separated list of debugging options; use [**pmdbg**(1)](/pmdbg/1.md) with the **-l** option to obtain a list of the available debugging options and their meaning.

Debugging options specific to **pmdatrace** are as follows:

| | |
| --- | --- |
| Option | Description |
| appl0 | authentication parsing, client changes, IPC, metric data and metadata refreshes |
| appl1 | raw data for rate metrics |

## SEE ALSO

[**PCPIntro**(1)](/PCPIntro/1.md), [**pmcd**(1)](/pmcd/1.md), [**pmtrace**(1)](/pmtrace/1.md), [**PMAPI**(3)](/PMAPI/3.md) and [**pmdatrace**(3)](/pmdatrace/3.md).