Skip to content
logo
Percona Server for MySQL
Improved InnoDB I/O scalability
Initializing search
    percona/psmysql-docs
    percona/psmysql-docs
    • Home
      • Release notes index
      • Percona Server for MySQL 8.0.33-25 Update (2023-08-02)
      • Percona Server for MySQL 8.0.33-25 (2023-06-15)
      • Percona Server for MySQL 8.0.32-24 (2023-03-20)
      • Percona Server for MySQL 8.0.31-23 (2023-02-09)
        • Percona Server for MySQL 8.0.30-22 Update (2022-11-21)
        • Percona Server for MySQL 8.0.30-22 (2022-11-21)
        • Percona Server for MySQL 8.0.29-21 (2022-08-08)
        • Percona Server for MySQL 8.0.28-20 (2022-06-20)
        • Percona Server for MySQL 8.0.28-19 (2022-05-12)
        • Percona Server for MySQL 8.0.27-18 (2022-03-02)
        • Percona Server for MySQL 8.0.26-17 (2022-01-26)
        • Percona Server for MySQL 8.0.26-16 (2021-10-20)
        • Percona Server for MySQL 8.0.25-15 (2021-07-13)
        • Percona Server for MySQL 8.0.23-14 (2021-05-12)
        • Percona Server for MySQL 8.0.22-13 (2020-12-14)
        • Percona Server for MySQL 8.0.21-12 (2020-10-13)
        • Percona Server for MySQL 8.0.20-11 (2020-07-21)
        • Percona Server for MySQL 8.0.19-10 (2020-03-23)
        • Percona Server for MySQL 8.0.18-9
        • Percona Server for MySQL 8.0.17-8
        • Percona Server for MySQL 8.0.16-7
        • Percona Server for MySQL 8.0.15-6
        • Percona Server for MySQL 8.0.15-5
        • Percona Server for MySQL 8.0.14
        • Percona Server for MySQL 8.0.13-4
        • Percona Server for MySQL 8.0.13-3
        • Percona Server for MySQL 8.0.12-2rc1
      • Limiting the disk space used by binary log files
      • Extended mysqlbinlog
      • Slow query log rotation and expiration
      • Extended SELECT INTO OUTFILE/DUMPFILE
      • Support for PROXY protocol
      • SEQUENCE_TABLE(n) function
      • Trigger updates
      • Expanded fast index creation
      • Kill idle transactions
      • Percona Toolkit UDFs
      • Utility user
      • The ProcFS plugin
      • Adaptive network buffers
      • Thread pool
      • Quickstart guide for Percona Server for MySQL
      • Install Percona Server for MySQL from repositories
        • Use APT repositories
        • Files in DEB package
        • Build APT packages
        • Downloaded DEB packages
        • Apt pinning
        • Run Percona Server for MySQL
        • Uninstall
        • Use RPM repositories
        • Files in RPM package
        • Downloaded RPM packages
        • Run Percona Server for MySQL
        • Uninstall
        • Install with binary tarballs
        • Binary tarballs available
        • Install Percona Server for MySQL from a source tarball
        • Compile Percona Server for MySQL 8.0 from source
        • Install using Docker
        • Docker environment variables
      • Upgrade guide
      • Upgrade using the Percona repositories
      • Upgrade from systems that use the MyRocks or TokuDB storage engine and partitioned tables
      • Upgrade using Standalone Packages
      • Downgrade
      • Binary logs and replication improvements
      • Post-installation
      • Working with AppArmor
      • Working with SELinux
      • Extended SHOW GRANTS
      • Backup and restore overview
      • Backup locks
      • Extended mysqldump
      • Start transaction with consistent snapshot
        • Using LDAP authentication plugins
        • LDAP authentication plugin system variables
      • Data masking
      • PAM authentication plugin
      • SSL improvements
      • Server variables
      • FIDO authentication plugin
      • Encryption functions
        • Data at Rest Encryption
        • Use the keyring component or keyring plugin
          • Using the Key Management Interoperability Protocol (KMIP)
          • Use the Amazon Key Management Service (AWS KMS)
          • Encrypt File-Per-Table Tablespace
          • Encrypt schema or general tablespace
          • Encrypt system tablespace
          • Encrypt temporary files
          • Encrypt Binary Log Files and Relay Log Files
          • Encrypting the Redo Log data
          • Encrypt the undo tablespace
          • Rotate the master key
          • Advanced encryption key rotation
          • Encrypt doublewrite buffers
          • Verify the encryption for tables, tablespaces, and schemas
      • Manage group replication flow control
      • Group replication system variables
      • Audit log plugin
      • Jemalloc memory allocation profiling
      • User statistics
      • Slow query log
      • Process list
      • Misc. INFORMATION_SCHEMA tables
      • Use Percona Monitoring and Management (PMM) Advisors
      • Too many connections warning
      • Handle corrupted tables
      • Thread based profiling
      • Stacktrace
      • Libcoredumper
        • The Percona XtraDB storage engine
        • Improved MEMORY storage engine
        • Improved InnoDB I/O scalability
          • Version specific information
          • System variables
            • innodb_flush_method
          • Status variables
        • Enforcing storage engine
        • Extended show engine InnoDB status
        • Show storage engines
        • Compressed columns with dictionaries
        • InnoDB full-text search improvements
        • XtraDB changed page tracking
        • XtraDB performance improvements for I/O-bound highly-concurrent workloads
        • Multiple page asynchronous I/O requests
        • Prefix index queries optimization
        • Limit the estimation of records in a Query
        • InnoDB page fragmentation counters
        • Percona MyRocks introduction
        • Percona MyRocks installation guide
        • Updated supported features
        • MyRocks limitations
        • Differences between Percona MyRocks and Facebook MyRocks
        • MyRocks Information Schema tables
        • MyRocks server variables
        • MyRocks status variables
        • Gap locks detection
        • Data loading
        • Installing and configuring Percona Server for MySQL with ZenFS support
        • TokuDB introduction
        • TokuDB installation
        • Use TokuDB
        • Fast updates with TokuDB
        • TokuDB files and file types
        • TokuDB file management
        • TokuDB background ANALYZE TABLE
        • TokuDB variables
        • TokuDB status variables
        • TokuDB fractal tree indexing
        • TokuDB troubleshooting
        • TokuDB Performance Schema integration
        • Frequently asked questions
        • Migrate and removing the TokuDB storage engine
        • Percona TokuBackup
      • List of variables introduced in Percona Server for MySQL 8.0
      • List of features available in Percona Server for MySQL releases
      • Percona Server for MySQL feature comparison
      • Understand version numbers
      • Development of Percona Server for MySQL
      • Trademark policy
      • Index of INFORMATION_SCHEMA tables
      • Frequently asked questions
      • Copyright and licensing information
      • Glossary

    • Version specific information
    • System variables
      • innodb_flush_method
    • Status variables

    Improved InnoDB I/O scalability¶

    Because InnoDB is a complex storage engine it must be configured properly in order to perform at its best. Some points are not configurable in standard InnoDB. The goal of this feature is to provide a more exhaustive set of options for XtraDB.

    Version specific information¶

    • 8.0.12-1: The feature was ported from Percona Server for MySQL 5.7.

    Note

    Implemented in Percona Server for MySQL 8.0.13-4, max checkpoint age has been removed because the information is identical to log capacity.

    System variables¶

    innodb_flush_method¶

    Option Description
    Command-line Yes
    Config file Yes
    Scope Global
    Dynamic No
    Data type Enumeration
    Default NULL
    Allowed values fsync, O_DSYNC, O_DIRECT, O_DIRECT_NO_FSYNC, littlesync, nosync

    The following values are allowed:

    * `fdatasync`: use `fsync()` to flush data, log, and parallel doublewrite files.
    
    * `O_SYNC`: use `O_SYNC` to open and flush the log and parallel doublewrite files; use `fsync()` to flush the data files. Do not use `fsync()` to flush the parallel doublewrite file.
    
    * `O_DIRECT`: use O_DIRECT to open the data files and `fsync()` system call to flush data, log, and parallel doublewrite files.
    
    * `O_DIRECT_NO_FSYNC`: use O_DIRECT to open the data files and parallel doublewrite files, but does not use the `fsync()` system call to flush the data files, log files, and parallel doublewrite files. Do not use this option for the *XFS* file system.
    
    * `ALL_O_DIRECT`: use O_DIRECT to open data files, log files, and parallel doublewrite files
    and use `fsync()` to flush the data files but not the log files or
    parallel doublewrite files. This option is recommended when *InnoDB* log files are big (more than 8GB), otherwise, there may be performance degradation.
    

    Note

    On an ext4 filesystem, set innodb_log_write_ahead_size to match the filesystem’s write-ahead block size. This variable avoids unaligned AIO/DIO warnings.

    Starting from Percona Server for MySQL 8.0.20-11, the innodb_flush_method affects doublewrite buffers exactly the same as in MySQL 8.0.20.

    Status variables¶

    The following information has been added to SHOW ENGINE INNODB STATUS to confirm the checkpointing activity:

    The max checkpoint age
    The current checkpoint age target
    The current age of the oldest page modification which has not been flushed to disk yet.
    The current age of the last checkpoint
    ...
    ---
    LOG
    ---
    Log sequence number 0 1059494372
    Log flushed up to   0 1059494372
    Last checkpoint at  0 1055251010
    Max checkpoint age  162361775
    Checkpoint age target 104630090
    Modified age        4092465
    Checkpoint age      4243362
    0 pending log writes, 0 pending chkp writes
    ...
    

    Contact us

    For free technical help, visit the Percona Community Forum.

    To report bugs or submit feature requests, open a JIRA ticket.

    For paid support and managed or consulting services , contact Percona Sales.


    Last update: 2023-05-09
    Percona LLC and/or its affiliates, © 2023
    Made with Material for MkDocs

    Cookie consent

    We use cookies to recognize your repeated visits and preferences, as well as to measure the effectiveness of our documentation and whether users find what they're searching for. With your consent, you're helping us to make our documentation better. Read more about Percona Cookie Policy.