Tracking Page Changes for Your Database and Bitmap Backups
This session will give an overview of a new feature in development in XtraDB and XtraBackup: tracking of changed InnoDB data pages to understand your workload, write patterns, and to enable fast incremental backups.
In this feature, XtraDB writes out the space, page id pairs of changed data pages between InnoDB checkpoints to a new disk file that uses compact bitmap representation. To make use of this information, new INFORMATION_SCHEMA tables have been introduced and we will present interesting and useful ways to query this information: understand write patterns in your data and identify the most accessed data pages.
Moreover, having this feature in XtraDB enables a new incremental backup algorithm in XtraBackup: as the bitmaps store all the changed page ids since a particular checkpoint, full data file scans are no longer necessary for incremental backups, saving I/Os. We will present the usage of this feature together with performance measurements.
The talk is intended for intermediate and advanced audience. The complexity of topics discussed will vary from sample INFORMATION_SCHEMA queries for understanding data access patterns to feature implementation details of interest to InnoDB engineers.