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  1. MariaDB Server
  2. MDEV-6664

Windows IOPS issue (slow read)



    • Bug
    • Status: Closed (View Workflow)
    • Major
    • Resolution: Not a Bug
    • 10.0.13
    • N/A
    • None
    • 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.


        1. Memory limited.PNG
          Memory limited.PNG
          9 kB
        2. PerfMon Disk MariaDB.PNG
          PerfMon Disk MariaDB.PNG
          12 kB
        3. PerfMon Disk SQL Server.PNG
          PerfMon Disk SQL Server.PNG
          10 kB
        4. Result MariaDB.PNG
          Result MariaDB.PNG
          27 kB
        5. Result SQL Server.PNG
          Result SQL Server.PNG
          25 kB
        6. Table.sql
          3 kB



            Unassigned Unassigned
            giordy Simone Giordano
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