Problems encountered when testing with mysqlslap

[Zhipan Wang]

Hi,

I was testing mysql server performance with mysqlslap. In the database there is a 'test' table with about 10,000 rows, and each row has a column 'id' as primary key and a column 'number' of type INT.

Command I used to do the test:

mysqlslap -h localhost -uuser -ppassword --create-schema=myschema --concurrency=64 --number-of-queries=64 --iterations=2 --query=query.sql

The problem was:
when iterations=1, it was always fine, and the result is like the following:
Benchmark
Average number of seconds to run all queries: 0.016 seconds
Minimum number of seconds to run all queries: 0.016 seconds
Maximum number of seconds to run all queries: 0.016 seconds
Number of clients running queries: 64
Average number of queries per client: 1

However, when iterations>=2, the command hangs sometimes, and even if it doesn't hang, the query duration is substantially longer. An example of the result with iterations=2 is:
Benchmark
Average number of seconds to run all queries: 0.808 seconds
Minimum number of seconds to run all queries: 0.015 seconds //my comment: first iteration?
Maximum number of seconds to run all queries: 1.602 seconds
Number of clients running queries: 64
Average number of queries per client: 1

The query (in query.sql) was simply 'SELECT * FROM test WHERE id=1000' where 1000 is a valid id. The mysql server is running on CentOS 6.3.

Did I do anything wrong in the test? or is there a likely incorrect configuration of the mysql server?

Thanks,
Zhipan



Edited 3 time(s). Last edit at 03/25/2013 12:56PM by Zhipan Wang.