# mysql profiler help

**URL:** <https://forums.percona.com/t/mysql-profiler-help/3317>\
**Category:** Other MySQL® Questions\
**Created:** [March 6, 2014, 5:56am UTC](https://forums.percona.com/t/mysql-profiler-help/3317 "2014-03-06T05:56:11Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![mixa](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/mixa/32/16881_2.png) [@mixa](https://forums.percona.com/u/mixa)\
**Post date:** [March 6, 2014, 5:56am UTC](https://forums.percona.com/t/mysql-profiler-help/3317/1 "2014-03-06T05:56:11Z")

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[COLOR=#3E454C] and read full of interesting article but i had a problem with mysl profiler. I was looking answer everywhere but didn’t find so i think maybe You can help me.

So:

I’m trying to use mysql profiler.  
I’m using the command:

set profiling=1;  
to turn it on.  
Later, i execute my query which is correlated subquery with EXISTS.  
It looks like:  
SELECT \* FROM A1 WHERE EXISTS (SELECT B1 FROM B2 WHERE B3=A2);

After that i use command:  
show profile;  
to see id of my query;  
mysql\> show profiles;  
±---------±-----------±-  
| Query\_ID | Duration| Query  
±---------±-----------±  
| 1 |1224.1249092 select …  
±---------±-----------±

But when i’m doing query to information\_schema.profiling for this query duration is much smaller. Why is such difference? Always displays 100 rows, and most of it is ‘sending data’. I can’t see ‘starting’ or ‘inicialization’ or ‘opening tables’. When i increase limit to 200 also displays 100 rows.

When i’m doing:  
select count(\*) from information\_schema.profiling where query\_id=1;  
It shows:

# count(\*) ‘100’

But when i’m doing:  
select \* from information\_schema.profiling where query\_id=1;  
SEQ starts from 1099931 and shows last 100 SEQ.

mysql\> select sum(duration) from information\_schema.profiling where query\_id=1;

# sum(duration)

12.234170

mysql\> show profile for query 1;  
executing 0.000003  
Sending data 0.004343  
executing 0.000003  
Sending data 0.293625  
executing 0.000003  
Sending data 0.294627  
executing 0.000003  
Sending data 0.293227  
executing 0.000003  
Sending data 0.293953  
executing 0.000004  
Sending data 0.293879  
executing 0.000004  
Sending data 0.293932  
executing 0.000003  
Sending data 0.293652  
executing 0.000003  
Sending data 0.003999  
executing 0.000002  
Sending data 0.292655  
executing 0.000004  
Sending data 0.295063  
executing 0.000005  
Sending data 0.296534  
executing 0.000003  
Sending data 0.295801  
executing 0.000004  
Sending data 0.296010  
executing 0.000004  
Sending data 0.004082  
executing 0.000003  
Sending data 0.297623  
executing 0.000004  
Sending data 0.317437  
executing 0.000003  
Sending data 0.301188  
executing 0.000004  
Sending data 0.301276  
executing 0.000004  
Sending data 0.295963  
executing 0.000004  
Sending data 0.300331  
executing 0.000004  
Sending data 0.296260  
executing 0.000003  
Sending data 0.004008  
executing 0.000002  
Sending data 0.294382  
executing 0.000004  
Sending data 0.310844  
executing 0.000005  
Sending data 0.295127  
executing 0.000006  
Sending data 0.005463  
executing 0.000003  
Sending data 0.296227  
executing 0.000003  
Sending data 0.302356  
executing 0.000004  
Sending data 0.294737  
executing 0.000004  
Sending data 0.295317  
executing 0.000004  
Sending data 0.314639  
executing 0.000003  
Sending data 0.296097  
executing 0.000005  
Sending data 0.297066  
executing 0.000003  
Sending data 0.294738  
executing 0.000003  
Sending data 0.315274  
executing 0.000004  
Sending data 0.296043  
executing 0.000003  
Sending data 0.293831  
executing 0.000003  
Sending data 0.294903  
executing 0.000003  
Sending data 0.293740  
executing 0.000003  
Sending data 0.294724  
executing 0.000005  
Sending data 0.297695  
executing 0.000004  
Sending data 0.294476  
executing 0.000003  
Sending data 0.297282  
executing 0.000004  
Sending data 0.298081  
executing 0.000003  
Sending data 0.297057  
executing 0.000004  
Sending data 0.004090  
end 0.000063  
query end 0.000006  
freeing items 0.000267  
logging slow query 0.000002  
logging slow query 0.000003  
cleaning up 0.000004

MySQL version 5.6.14 but I also try 5.5 and 5.1 and result is the same.  
Any help? Please ! I’m helpless!

– Izabela Stalończyk