focal (8) mysqld_qslower-bpfcc.8.gz

Provided by: bpfcc-tools_0.12.0-2_all bug

NAME
       mysqld_qslower - Trace MySQL server queries slower than a threshold.


SYNOPSIS
       mysqld_qslower PID [min_ms]


DESCRIPTION
       This  traces  queries  served  by  a  MySQL  server, and prints those that exceed a custom latency (query
       duration) threshold. By default, a minimum threshold of 1 millisecond is used. If a  threshold  of  0  is
       used, all queries are printed.

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


OPTIONS
       PID Trace this mysqld PID.

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


EXAMPLES
       Trace MySQL server queries slower than 1 ms for PID 1981:
              # mysqld_qslower 1981

       Trace slower than 10 ms for PID 1981:
              # mysqld_qslower 1981 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 128 characters.


OVERHEAD
       This  adds low-overhead instrumentation to MySQL 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
       Brendan Gregg


SEE ALSO
       biosnoop(8)