… columns (BLOB, VARCHAR, TEXT) in the index record, and the remainder stored in overflow pages. COMPACT became the default after MySQL 5…? As the fine MySQL manual states: This setting may still be useful for tables with many long BLOB, VARCHAR or TEXT columns…-build the table using ALTER TABLE via a null-operation like this: ALTER TABLE `t1` ENGINE=InnoDB ROW_FORMAT=COMPRESSED KEY…
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 5 Comments
…painful troubleshooting tasks with MySQL is troubleshooting memory usage. The problem usually starts like this – you have configured MySQL to use reasonable global…might look at how it uses MySQL to identify potential causes. Is it working with large blobs ? Using user variables ? Prepared Statements…
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… freed clustered index pages unavailable to the BLOB allocation. This function is also a likely culprit of InnoDB hangs that were observed… of a mini-transaction allocated (nonfree=TRUE) before storing the BLOBs, or freed (nonfree=FALSE) before committing the mini-transaction. btr…
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… bytes. These are 5 bytes where different flags are stored like “record is deleted” flag. The last two bytes are the… values format. BLOBs are printed in a hex form – 0ACD86… To upload the table back you should utilize UNHEX function: mysql> LOAD…
Post: MySQL Server Memory Usage
May 17, 2006 By 21 Comments
… also add the size of Operation System cache you would like MySQL to use for your table. Take this number add to… to be impractical. Here is why: List of rarely considered MySQL Server Memory Requirements Thread buffers can be allocated more than… have unbound memory requirements retriving result sets from remove queries. Blobs may require 3x time of memory. This is important if…
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
… enable logging atomically, not just for new connections as in MySQL. This is very helpful for measurement as otherwise we might… say if you were using the vanilla MySQL server, you would see an entry like this in the slow query log: # Time…, probably selecting only the needed columns which could exclude the blob ones. Conclusion The only conclusion, I can make out is…
Post: Adventures in archiving
February 11, 2013 By 16 Comments
… further testing. InnoDB’s inbuilt row compression MySQL‘s inbuilt compress() function leveraging zlib to … ( `id` int(11) NOT NULL AUTO_INCREMENT, `dat` blob, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1… is a list reduced to the most likely to affect production deployments. Use of Auto …
Post: State of MySQL Market and will Replication live ?
April 9, 2008 By 29 Comments
…no vendor lock in” policy and would not like proprietary solutions, another – typically ones having already … to these requirements ? From MySQL side we have further development of MySQL Cluster to be more … streaming to make it possible store large blobs such as images in the database efficiently. …
Post: 10+ Ways to Crash or Overload MySQL
November 13, 2007 By 20 Comments
… keep max_prepared_stmt_count very low. Prepared Statements and Blob Data If you’re want to get memory consumed by… subtables will likely cause your MySQL server to run out of file descriptors. The same is true for Partitioned tables in MySQL 5… you can see from these points it does not looks like MySQL tries to make server bullet proof if somebody tries to…
Post: Percona Testing: Innodb crash / recovery tests available
December 21, 2011 By Leave a Comment
… unfortunately, no tests have been created for the main MySQL branch. The MySQL at Facebook branch has a number of tests that… master has crashed and restarted: $ ./kewpie.py –suite=innodbCrash –basedir=mysql-5.5 –test-debug crashCommitAfter_test 20111221-142500 INFO MASTER…, but I also haven’t dug into partitions or blobs >: ) If you’d like to try these out yourself, they are in…
