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 latencies. 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:
       -DENABLE_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 overhead 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, output, and commentary for this tool.

OS

       Linux

STABILITY

       Unstable - in development.

AUTHOR

       Sasha Goldshtein

SEE ALSO

       dbslower(8)