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MySQL 5.7 Reference Manual  /  ...  /  mysqldumpslow — Summarize Slow Query Log Files

4.6.8 mysqldumpslow — Summarize Slow Query Log Files

The MySQL slow query log contains information about queries that take a long time to execute (see Section 5.4.5, “The Slow Query Log”). mysqldumpslow parses MySQL slow query log files and summarizes their contents.

Normally, mysqldumpslow groups queries that are similar except for the particular values of number and string data values. It abstracts these values to N and 'S' when displaying summary output. To modify value abstracting behavior, use the -a and -n options.

Invoke mysqldumpslow like this:

shell> mysqldumpslow [options] [log_file ...]

Example of usage:

shell> mysqldumpslow

Reading mysql slow query log from /usr/local/mysql/data/mysqld57-slow.log
Count: 1  Time=4.32s (4s)  Lock=0.00s (0s)  Rows=0.0 (0), root[root]@localhost
 insert into t2 select * from t1

Count: 3  Time=2.53s (7s)  Lock=0.00s (0s)  Rows=0.0 (0), root[root]@localhost
 insert into t2 select * from t1 limit N

Count: 3  Time=2.13s (6s)  Lock=0.00s (0s)  Rows=0.0 (0), root[root]@localhost
 insert into t1 select * from t1

mysqldumpslow supports the following options.

Table 4.21 mysqldumpslow Options

Format Description
-a Do not abstract all numbers to N and strings to 'S'
-n Abstract numbers with at least the specified digits
--debug Write debugging information
-g Only consider statements that match the pattern
--help Display help message and exit
-h Host name of the server in the log file name
-i Name of the server instance
-l Do not subtract lock time from total time
-r Reverse the sort order
-s How to sort output
-t Display only first num queries
--verbose Verbose mode

  • --help

    Display a help message and exit.

  • -a

    Do not abstract all numbers to N and strings to 'S'.

  • --debug, -d

    Run in debug mode.

  • -g pattern

    Consider only queries that match the (grep-style) pattern.

  • -h host_name

    Host name of MySQL server for *-slow.log file name. The value can contain a wildcard. The default is * (match all).

  • -i name

    Name of server instance (if using mysql.server startup script).

  • -l

    Do not subtract lock time from total time.

  • -n N

    Abstract numbers with at least N digits within names.

  • -r

    Reverse the sort order.

  • -s sort_type

    How to sort the output. The value of sort_type should be chosen from the following list:

    • t, at: Sort by query time or average query time

    • l, al: Sort by lock time or average lock time

    • r, ar: Sort by rows sent or average rows sent

    • c: Sort by count

    By default, mysqldumpslow sorts by average query time (equivalent to -s at).

  • -t N

    Display only the first N queries in the output.

  • --verbose, -v

    Verbose mode. Print more information about what the program does.


User Comments
User comments in this section are, as the name implies, provided by MySQL users. The MySQL documentation team is not responsible for, nor do they endorse, any of the information provided here.
  Posted by Muruges Muthu on December 19, 2011
Count: 19 Time=11.16s (212s) Lock=0.00s (0s) Rows=1.0 (19) ...

Read the results as, this particular query got executed 19 times and 'Time=<Average time taken for one execution 11.16 seconds> (<Time taken for all 19 executions 212 seconds>)' ...
  Posted by Rick James on February 2, 2016
Which -s option should I use? Here are my tips:

`-s t` says to start with the queries that have the most impact on the server. If your system is having general performance problems, use that.

`-s at` is good for looking for queries that are the most sluggish to the end-users.
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