gpmt analyze_session

This tool traces busy processes associated with a Greenplum Database session. The information collected can be used by VMware Support for root cause analysis on hung sessions.

Usage

  1. gpmt analyze_session [-session <session_id> ] [-master-dir <directory>] 
  2. [-segment-dir <directory>]

Options

-session

Greenplum session ID which is referenced in pg_stat_activity.

-master-dir

Working directory for master process.

-segment-dir

Working directory for segment processes.

-free-space

Free space threshold which will exit log collection if reached. Default value is 10%.

-a

Answer Yes to all prompts.

Examples

Collect process information for a given Greenplum Database session id:

  1. gpmt analyze_session -session 12345

The tool prompt gives a high-level list of only the servers that are running busy processes and how processes are distributed across the Greenplum hosts. This gives an idea of what hosts are busier than others, which might be caused by processing skew or other environmental issue with the affected hosts.

Note: lsof, strace, pstack, gcore, gdb must be installed on all hosts. gcore will perform a memory dump of the Greenplum process and the size could be anywhere from 300MB to several Gigabytes. Isolating which hosts to collect using the gpmt global option -hostfile to limit the collection size.