June 19, 2013

Post: Is your MySQL buffer pool warm? Make it sweat!

… the option innodb_fake_changes to prevent INSERTs, UPDATEs, and DELETEs from corrupting the data on the standby server. You will… our production systems. We restored a production database backup to our test database so that our test database was consistent before applying the captured query…

Post: Concatenating MyISAM files

…lib/mysql/test# cat test_concat_part.MYD >> test_concat.MYD root@django:/var/lib/mysql/test# myisamchk -rq test_concat – check record delete-chain – …mysql: mysql> use test Database changed mysql> flush tables; Query OK, 0 rows affected (0.00 sec) mysql> select * from test_concat; +—-+ | id…

Post: Recovery deleted ibdata1

… this fact and it allowed to salvage the database. Actually, the files were deleted long time ago – 6 months or so. As… possible to recover database fast. Let me illustrate how. Let’s simulate the accident. For that I will delete /var/lib/mysql…, using mysql Running the test with following options: Number of threads: 16 Doing OLTP test. Running mixed OLTP test Using Special distribution (12…

Comment: Database problems in MySQL/PHP Applications

… key references may add processing time to inserts, updates, and deletes but there are other benefits. Also – if you’re replicating… > with almost empty database. With database growth it will however start > to crawl. > So developing you PHP applications use test database with reasonable > amount…

Comment: How To Test Your Upgrades - pt-upgrade

I have got full query log including insert, delete and update as well. Should I parse to pt-query-… be slow query format? Second question is doest these test table and test databases are human created or they are being created as… –compare results,warnings –compare-results-method rows –limit 100% –temp-database pt_upgrade –clear-warnings-table pt_upgrade.temp –continue-on…

Post: Using Flexviews - part two, change data capture

… synchronously Database log reading to capture the changes asynchronously The first method has serious drawbacks, such that it can’t identify deleted…: 2 Duplicates: 0 Warnings: 0 And delete data in a second transaction: mysql> delete from test.demo where c1=1; Query OK, 1 row affected (0.00 sec) The changelog is flexviews.test_demo. This…

Post: InnoDB Full-text Search in MySQL 5.6 (part 1)

… tablespace files in our database directory: -rw-rw—-. 1 mysql mysql 8632 Feb 20 15:54 dir_test_innodb.frm -rw-rw… OPTIMIZE or two, delete some data, and see what happens: mysql> set global innodb_ft_aux_table=’test/dir_test_innodb’; mysql> set…) mysql> delete from dir_test_innodb LIMIT 200000; Query OK, 200000 rows affected (8.65 sec) mysql> optimize table dir_test_innodb; +———————-+———-+———-+———-+ | Table…

Post: SHOW INNODB STATUS walk through

… fails for table `test/child`: , CONSTRAINT `child_ibfk_1` FOREIGN KEY (`parent_id`) REFERENCES `parent` (`id`) ON DELETE CASCADE Trying to add… pool allocated 16773888 Buffer pool size 262144 Free buffers 0 Database pages 258053 Modified db pages 37491 Pending reads 0 Pending… in buffer pool, number of pages free, pages allocated by database pages and dirty pages. From these values you can learn…

Post: Recovering Innodb table Corruption

test“.”test“) InnoDB: Database

Post: Paul McCullagh answers your questions about PBXT

… and InnoDB/XtraDB. Tests show that PBXT’s performance is similar to InnoDB but, depending on your database designed and the application…? This is no longer necessarily the case. For example a test (http://mysqlha.blogspot.com/2009/03/pbxt-is-fast-no… recognizes which record versions are no longer needed and deletes them from the database. The Checkpointer flushes the data written by the…