Hi Alex/Vadim, We had install mysql-server-wsrep-5.5.20-23.4 with galera-23….] WSREP: Failed to prepare for incremental state transfer: Local state UUID (00000000-0000-0000-0000-000000000000) does not match group state UUID (8630f2a8-7be8-11e1-0800-7e1ae413f999): 1 (Operation not permitted) Apr …
Post: To UUID or not to UUID ?
March 13, 2007 By 28 Comments
… is however completely separate problem which can be fixed in MySQL 5.1 Data Clustering This again applies to Innodb tables… set is large auto_increment would work much better than UUID because UUID will have recent data scattered all across. Lookups Later… of 40305 rows/sec. For UUID process took over 12 hours and is still going. From MySQL status I can see it…
Post: Recovering Linux software RAID, RAID5 Array
August 27, 2011 By 2 Comments
Dealing with MySQL you might need to deal with RAID recovery every so … : 1 Layout : left-symmetric Chunk Size : 64K Name : 001F33EABA01:2 UUID : 01a26106:50b297a8:1d542f0a:5c9b74c6 Events : 83 Number Major Minor RaidDevice… Offset : 8 sectors Recovery Offset : 5631463944 sectors State : clean Device UUID : 77ea1f91:5d4915c3:5cd17402:7f1ecafb Update Time : Fri Aug 26 22…
Post: Impact of the sort buffer size in MySQL
October 25, 2010 By 8 Comments
… UUID=`uuidgen` mysql test -e “insert into sorttest value (‘$UUID‘);” let “COUNT=COUNT+1″ done I know, I could have used the uuid() function of MySQL… important point here, at least for the Linux, glibc and MySQL versions I used and for the test I did, there…
Post: MySQL Partitioning - can save you or kill you
December 11, 2010 By 14 Comments
I wanted for a while to write about using MySQL Partitioning for Performance Optimization and I just got a relevant … mainly due to modifying the uu index. This is because UUID() spreads values prefix very well effectively giving almost uniform access… does not exist, which reduced performance for random selects by UUID from 400 to 20 per second (from single thread). Decreasing…
Post: MySQL Query Cache
July 27, 2006 By 69 Comments
… great feature called “Query Cache” which is quite helpful for MySQL Performance optimization tasks but there are number of things you… works with current data, uses non-deterministic functions such as UUID(), RAND(), CONNECTION_ID() etc it will not be cached. Table… lets speak a bit about Query Cache configuration and mainance. MySQL Manual is pretty good on this: Query Cache Query Cache…
Post: Make your file system error resilient
August 24, 2011 By 8 Comments
…-2010) Filesystem volume name: Last mounted on: /mnt/data Filesystem UUID: f9f7a0c3-0350-46d5-9930-29c3ac1f4b32 Filesystem magic number: 0xEF53 Filesystem… is probably not needed for partition you store MySQL data on, as chances are MySQL server is only one doing writes on… as needed, same as you would every so often check MySQL tables for corruption. To change those options you can run…
Comment: To UUID or not to UUID ?
April 20, 2010 By 28 Comments
… you already “know” when you store it. Portions of the UUID never change when generated on the same server, so if…: $uuid = substr($uuid, 0, 
. substr($uuid, 9, 4) . substr($uuid, 14, 4) . substr($uuid, 19, 4); where $uuid is the result of doing a SELECT UUID() in MySQL…
Comment: To UUID or not to UUID ?
April 15, 2008 By 28 Comments
… have seen those problems with UUID‘s in MySQL when stored as text. Ideally, MySQL would have a UUID column type to store the… improve the situation, I created a simple UUID class capable of generating random UUID‘s with an option to store them in… conversion and come up with a case-sensitive 22-byte UUID representation (VTIW7xOgReOGrL3vMRjm4Q, for example). The performance increase was enormous, and…
Comment: To UUID or not to UUID ?
July 20, 2010 By 28 Comments
… PHP/MySQL, I suggest this approach. First simply SELECT REVERSE(UNHEX(REPLACE(UUID(),’-',”))); this will give us the UNHEXed and REVERSEd UUID in… the database later, you call SELECT HEX(REVERSE(‘{$uuid}’)); And to make the UUID look more “natural,” simply run strtolower() to remove…
