… MySQL is troubleshooting memory usage. The problem usually starts like this – you have configured MySQL to use reasonable global buffers, such as innodb… might look at how it uses MySQL to identify potential causes. Is it working with large blobs ? Using user variables ? Prepared Statements…
Post: Blob Storage in Innodb
February 9, 2010 By 13 Comments
… blob can be stored on the page. However if row does not fit on the page, for example containing two 7KB blobs Innodb will have to pick some of them and store them in external blob pages. It however will… bytes of the BLOB may look strange, especially as MySQL internally has no optimizations to read portions of the blob – it is either…
Post: MySQL Blob Compression performance benefits
January 11, 2008 By 17 Comments
…compressed. Unfortunately MySQL does not provide compressed BLOB/TEXT columns (I would really love to have COMPRESSED attribute for the BLOB/TEXT columns… with true data size and performance gains, especially for Innodb tables. With Innodb tables BLOB gets its own page (allocated outside of clustered…
Post: Percona Testing: Innodb crash / recovery tests available
December 21, 2011 By Leave a Comment
… may know this, but there are precious few innodb crash recovery tests available. Some folks have noticed … no tests have been created for the main MySQL branch. The MySQL at Facebook branch has a number of … but I also haven’t dug into partitions or blobs >: ) If you’d like to try these out yourself…
Post: Bug#12704861
November 20, 2011 By 1 Comment
… in MySQL 5.1.60. I’ll repeat here the full documentation from the release notes: “InnoDB Storage Engine: Data from BLOB columns… are into InnoDB internals: The fix of Bug#12612184 broke crash recovery. When a record that contains off-page columns (BLOBs) is… clustered index pages unavailable to the BLOB allocation. This function is also a likely culprit of InnoDB hangs that were observed when…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 17 Comments
… little known new features in MySQL 5.1 Q15: How frequently does Innodb fuzzy checkpointing is activated HT: InnoDB flushes about 128 dirty… than 8100 bytes InnoDB will not allocate additional space for blobs, even if each blob is larger than 768. 2. InnoDB will allocate additional… serialization. MySQL‘s binlog and InnoDB‘s log must have the transactions in the same order, for a recovery based on MySQL‘s…
Post: Recover BLOB fields
July 1, 2010 By 4 Comments
… types like BLOB, TEXT were not supported by Percona InnoDB Recovery Tool. The reason consists in a special way InnoDB stores BLOBs. An InnoDB table…), PRIMARY KEY (`ID`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 Here COMPACT format is used, which is default in MySQL >= 5.1. The record… values format. BLOBs are printed in a hex form – 0ACD86… To upload the table back you should utilize UNHEX function: mysql> LOAD…
Post: Innodb row size limitation
April 7, 2011 By 11 Comments
…, fterms TEXT, PRIMARY KEY (id) ) Engine=InnoDB; Now you insert some test data into it: mysql> INSERT INTO example -> VALUES ( ->Â Â… length columns and the complete row size exceeds this limit, InnoDB chooses variable length columns for off-page storage. In these… specific, see http://www.mysqlperformanceblog.com/2010/02/09/blob-storage-in-innodb/ for further reference). It’s worth mentioning that this…
Post: Innodb undo segment size and transaction isolation
January 12, 2011 By 2 Comments
… Percona Server it is easy to check: mysql> select * from information_schema.innodb_rseg; +———+———-+———-+———+————+———–+ | rseg_id | space_id | zip_size | … will require more space, depending on row size. Long blobs (the ones which are not stored on the page) …
Comment: Blob Storage in Innodb
February 10, 2010 By 13 Comments
… imagine a blob that is 1 GB in size and you have 25 conncurrent requests for such a sized blob, innodb will need to allocate 25 GB of memory to satisfy this query. See: http://mysqlinsights.blogspot.com/2009/01/mysql-blobs-and-memory-allocation.html The people at pbxt have created a solution for their storage engine using a streaming blob…
