bcc-mysqld_qslower(8)

1mysqld_qslower(8)           System Manager's Manual          mysqld_qslower(8)
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NAME

6       mysqld_qslower - Trace MySQL server queries slower than a threshold.
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SYNOPSIS

9       mysqld_qslower PID [min_ms]
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DESCRIPTION

12       This  traces  queries  served  by a MySQL server, and prints those that
13       exceed a custom latency (query duration) threshold. By default, a mini‐
14       mum  threshold  of  1 millisecond is used. If a threshold of 0 is used,
15       all queries are printed.
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17       This uses User Statically-Defined  Tracing  (USDT)  probes,  a  feature
18       added  to  MySQL  for DTrace support, but which may not be enabled on a
19       given MySQL installation. See requirements.
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21       Since this uses BPF, only the root user can use this tool.
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REQUIREMENTS

24       CONFIG_BPF, bcc, and MySQL server with USDT probe support (when config‐
25       uring the build: -DENABLE_DTRACE=1).
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OPTIONS

28       PID Trace this mysqld PID.
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30       min_ms Minimum  query  latency  (duration)  to  trace, in milliseconds.
31              Default is 1 ms.
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EXAMPLES

34       Trace MySQL server queries slower than 1 ms for PID 1981:
35              # mysqld_qslower 1981
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37       Trace slower than 10 ms for PID 1981:
38              # mysqld_qslower 1981 10
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FIELDS

41       TIME(s)
42              Time of query start, in seconds.
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44       PID    Process ID of the traced server.
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46       MS     Milliseconds for the query, from start to end.
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48       QUERY  Query string, truncated to 128 characters.
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OVERHEAD

51       This adds low-overhead instrumentation to MySQL queries, and only emits
52       output data from kernel to user-level if they query exceeds the thresh‐
53       old. If the server query rate is less than 1,000/sec, the  overhead  is
54       expected  to  be negligible. If the query rate is higher, test to gauge
55       overhead.
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SOURCE

58       This is from bcc.
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60              https://github.com/iovisor/bcc
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62       Also look in the bcc distribution for a  companion  _examples.txt  file
63       containing example usage, output, and commentary for this tool.
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OS

66       Linux
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STABILITY

69       Unstable - in development.
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AUTHOR

72       Brendan Gregg
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