NAME

       dbslower - Trace MySQL/PostgreSQL server queries slower than a threshold.

SYNOPSIS

       dbslower [-v] [-p PID [PID ...]] [-x PATH] [-m THRESHOLD] {mysql,postgres}

DESCRIPTION

       This traces queries served by a MySQL or PostgreSQL server, and prints those that exceed a
       latency (query time) threshold. By default a threshold of 1 ms is used.

       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.  Alternatively, MySQL queries can be traced without the USDT  support  using
       the -x option.

       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.

       -x PATH
              Path to MySQL binary. This option allow to MySQL  queries  even  when  USDT  probes
              aren't enabled on the MySQL server.

       -m THRESHOLD
              Minimum query latency (duration) to trace, in milliseconds. Default is 1 ms.

       {mysql,postgres}
              The database engine to trace.

EXAMPLES

       Trace MySQL server queries slower than 1 ms:
              # dbslower mysql

       Trace slower than 10 ms for PostgreSQL in process 408:
              # dbslower postgres -p 408 -m 10

FIELDS

       TIME(s)
              Time of query start, in seconds.

       PID    Process ID of the traced server.

       MS     Milliseconds for the query, from start to end.

       QUERY  Query string, truncated to 256 characters.

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, Brendan Gregg

SEE ALSO

       biosnoop(8), mysqld_qslower(8), dbstat(8)