…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 18 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: 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…
Post: MySQL EXPLAIN limits and errors.
July 24, 2006 By 6 Comments
… how many rows will be examined MySQL will still print full number. Here is example: mysql> explain select * from lt limit 10… known – for example BLOB fields can’t work with in memory temporary table. The other thing – since MySQL 4.1 sorting can… like structure of opertions applied to the data, methods used, costs etc. Simple table like output format is good but with growing MySQL…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 17 Comments
… 8100 bytes InnoDB will not allocate additional space for blobs, even if each blob is larger than 768. 2. InnoDB will allocate… distant future, I would like to have the memlock also. PZ: memlock already works – it is global MySQL Server option, though it… a LARGE value (somewhat like 200) for additional throughput? HT: ha_innodb.cc in 5.1: static MYSQL_SYSVAR_ULONG(thread_concurrency…
