Status: Closed (View Workflow)
Resolution: Not a Bug
Windows 7 x64, SSD disk
There is something strange on disk usage (IOPS) on Windows version.
I'm doing some tests porting an ERP archive from SQL Server to MariaDB.
The test archive is a ledger table with 22.800.000 rows, each rows has 69 columns for a total row length of 832 bytes.
There is a primary key which is an autoincrement.
On the same machine (i5 4 core, Samsung SSD 840) there is a big difference between SQL Server and MariaDB.
My test is with a query without indexes (ex. search for a specific value or GROUP BY and SUM) so the engine have to do a full table scan.
I need this type of test (obviously I can speed up the query with an index).
Each engine is limited to 2 GB of RAM (for MariaDB with innodb_buffer_pool_size).
Same query repeated a lot of times, takes about 30sec for a full table scan on SQL Server and about 90sec with MariaDB. 3x times!
Watching filesystem activity with Performance Monitor, I've seen that SQL Server can reach 400/450 MB/sec reading its MDF file.
MariaDB is stuck at 150 MB/sec to read IDB file.
I've tried with innodb_io_capacity parameter but without lucky.
In attachment you find table structure and some screenshots.