Within the MySQL data directory, the InnoDB storage engine creates two types of files — the data files and the redo log files. Each data file (or ibd file) belongs to exactly one tablespace. Each tablespace is given a unique identifier called the space_id. …
Category Archives: InnoDB
Some Notes on Index Statistics in InnoDB
In MySQL 5.6 we introduced a huge improvement in the way that index and table statistics are gathered by InnoDB and subsequently used by the Optimizer during query optimization: Persistent Statistics. Some aspects of the way that Persistent Statistics work could be improved further though, and we’d really like your input on that.…
Resizing the InnoDB Buffer Pool Online
As described in the MySQL 5.7 manual here, we can now resize the buffer pool without restarting the mysqld process starting with MySQL 5.7.5.
You can now use the "SET GLOBAL innodb_buffer_pool_size = xxxx" command which causes a resizing job to begin in background.…
InnoDB General Tablespaces – Preview
The new InnoDB Labs release contains the ability to create and use independent multi-table general tablespaces.
This feature will provide a way to group tables together into tablespaces at a location and filename of your choosing. Tables using row formats of Redundant, Compact, and Dynamic can be combined together into the same general tablespace. …
New InnoDB Memcached Functionality in 5.7 Lab Release
InnoDB Memcached’s read only query performance in 5.7 has already achieved a remarkable 1.1 million QPS record. Now, the read only query bottleneck shifts to the memcached client itself. Thus anything that can batch the queries and shorten the query strings helps.…
Online Truncate of InnoDB UNDO Tablespaces
We have received a lot of requests from our user community regarding the ability to truncate UNDO tablespaces (‘truncate’ here means that the size of the tablespace is reset back to what it was when it was first created). We are happy to say that we’ve now been able to implement this anticipated feature.…
About the Data Dictionary Labs Release
For a long time, the MySQL development community and many others have wanted a server that worked without FRM files. The motivation behind removing FRM files, and the design goals around new data dictionary, can be explored in more detail in the blog post by Ståle Deraas “A New Data Dictionary for MySQL”.…
The MySQL 5.7.5 Milestone Release is Available
The MySQL Development team is happy to announce our 5.7.5 development milestone release (DMR), now available for download at dev.mysql.com. You can find the full list of changes and bug fixes in the 5.7.5 release notes. Here are the highlights.…
Externally Stored Fields in InnoDB
This article discusses the storage (inline and external) of field data in the InnoDB storage engine. All fields of variable length types like VARCHAR, VARBINARY, BLOB and TEXT can be stored inline within the clustered index record, or stored externally in separate BLOB pages outside of the index record (but within the same tablespace).…
Improving Innochecksum
In WL#6045 we improved the innochecksum tool so that it opens the tablespace file and validates the checksum for each page. It compares the calculated checksum to the stored checksum in the page and reports mismatches, if any. It can also now rewrite page checksums in the tablespace.…