… is however completely separate problem which can be fixed in MySQL 5.1 Data Clustering This again applies to Innodb tables…” items more frequently and data set is large auto_increment would work much better than UUID because UUID will have recent data scattered… 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
…with MySQL you might need to deal with RAID recovery every …1 Layout : left-symmetric Chunk Size : 64K Name : 001F33EABA01:2 UUID : 01a26106:50b297a8:1d542f0a:5c9b74c6 Events : 83 Number Major Minor…Fri Aug 26 13:51:11 2011 mdadm: size set to 2925544704K Continue creating array? y mdadm: Defaulting to…
Post: Impact of the sort buffer size in MySQL
October 25, 2010 By 8 Comments
… UUID=`uuidgen` mysql test -e “insert into sorttest value (‘$UUID‘);” let “COUNT=COUNT+1″ done I know, I could have used the uuid() function of MySQL… `seq 1 1000` do START=`date +%s.%N` OUT=`mysql -e “set session sort_buffer_size=32*1024*$i;select * from sorttest…
Post: MySQL Query Cache
July 27, 2006 By 69 Comments
… execution plans are cached. MySQL Query Cache is not. It does not cache the plan but full result sets. This means it… works with current data, uses non-deterministic functions such as UUID(), RAND(), CONNECTION_ID() etc it will not be cached. Table… of them quite likely would not have change their result set but MySQL has no way to identify which one of them…
Post: Make your file system error resilient
August 24, 2011 By 8 Comments
…volume name: Last mounted on: /mnt/data Filesystem UUID: f9f7a0c3-0350-46d5-9930-29c3ac1f4b32 Filesystem magic …depending on which filesystem became read only) To set error behavior to different value run tune2fs … needed for partition you store MySQL data on, as chances are MySQL server is only one …
Post: Using CHAR keys for joins, how much is the overhead ?
June 18, 2007 By 18 Comments
… row in set (1.70 sec) Here is explain if someone curious, it did not really change beside key lengths: mysql> explain… convert Innodb table to latin1 character set. I was expected this to shorten some internal buffers MySQL has to allocate for key… was – latin1 encoding is enough for most character based keys – uuid, sha1/md5 based etc. Latin1 encoding indeed gave significant improvement…
Post: Thinking about running OPTIMIZE on your Innodb Table ? Stop!
December 9, 2010 By 13 Comments
…inserts in very random order, such as indexes on UUID column or something similar. It also produces a …| optimize | status | OK | +——–+———-+———-+——————————————————————-+ 2 rows in set (4 min 5.52 sec) mysql> alter table a add key(c); Query…
Post: Stored Function to generate Sequences
April 2, 2008 By 15 Comments
…which also can be helpful: mysql> select seq(‘one’),seq(‘two’),seq(‘one… +————+————+————+————+ | 102 | 1002 | 103 | 104 | +————+————+————+————+ 1 row in set (0.00 sec) I… caching them in applications, using UUID_SHORT() and other methods …
