Manual: dbstat-bpfcc

dbstat(8)				   System Manager's Manual				   dbstat(8)

NAME
       dbstat - Collect histograms of MySQL/PostgreSQL query latencies.

SYNOPSIS
       dbstat [-v] [-p PID [PID ...]] [-m THRESHOLD] [-u] [-i INTERVAL] {mysql,postgres}

DESCRIPTION
       This  traces queries served by a MySQL or PostgreSQL server, and collects a histogram of query laten‐
       cies. The histogram is printed at the end of collection, or at specified intervals.

       This uses User Statically-Defined Tracing (USDT) probes, a feature added to MySQL and PostgreSQL	 for
       DTrace support, but which may not be enabled on a given installation. See requirements.

       Since this uses BPF, only the root user can use this tool.

REQUIREMENTS
       CONFIG_BPF,  bcc,  and  MySQL  server  with  USDT  probe	 support  (when configuring the build: -DEN‐
       ABLE_DTRACE=1) or PostgreSQL server with USDT probe support (when configuring  the  build:  --enable-
       dtrace).

OPTIONS
       -h Print usage message.

       -p PID Trace  this  PID.	 If  no	 PID is specified, the tool will attempt to automatically detect the
	      MySQL or PostgreSQL processes running on the system.

       -m THRESHOLD
	      Minimum query latency (duration) to trace, in milliseconds.  Default is all queries.

       -u     Display query latencies in microseconds (default: milliseconds).

       -i INTERVAL
	      Print summaries (histograms) at this interval, specified in seconds.

       {mysql,postgres}
	      The database engine to trace.

EXAMPLES
       Display histogram of MySQL query latencies:
	      # dbstat mysql

       Display histogram of PostgreSQL query latencies slower than 10ms in pid 408:
	      # dbstat postgres -p 408 -m 10

       Display histogram of PostgreSQL query latencies at 3-second intervals:
	      # dbstat postgres -i 3

OVERHEAD
       This adds low-overhead instrumentation to queries, and only emits output data from  kernel  to  user-
       level if they query exceeds the threshold. If the server query rate is less than 1,000/sec, the over‐
       head is expected to be negligible. If the query rate is higher, test to gauge overhead.

SOURCE
       This is from bcc.

	      https://github.com/iovisor/bcc

       Also  look  in the bcc distribution for a companion _examples.txt file containing example usage, out‐
       put, and commentary for this tool.

OS
       Linux

STABILITY
       Unstable - in development.

AUTHOR
       Sasha Goldshtein

SEE ALSO
       dbslower(8)

USER COMMANDS					 2017-02-15					   dbstat(8)