June 20, 2013

Post: Percona Server 5.1.69-14.7 now available: A drop in replacement for MySQL

in replacement for MySQL, downloads are available  here and from the Percona Software Repositories. Based on MySQLrecords are overwritten by the new log data. In some corner cases this could lead to assertion errors intables in INFORMATION_SCHEMA (CLIENT_STATISTICS, INDEX_STATISTICS, TABLE…, deleting

Post: MySQL Query Patterns, Optimized - Webinar questions followup

MySQL Query Patterns, Optimized” for Percona MySQL Webinars.  If you missed it, you can still register to view the recording… certain insert/update/delete operations.  If you …in this case to force MySQL to scan the `title` table first, grouping by kind_id in index order.  This made the first table in

Comment: MySQL Partitioning - can save you or kill you

… _no_ parallel queries (within a single connection) anywhere in any ‘free’ variant of MySQL. PARTITIONs are scanned one at a time. (Please… “delete records from this table, those will be quicker, as they will come out of the partition, not the whole table“: * If the DELETE is… one record. PARTITIONing makes very little difference. * If it cannot prune, then partitioned would be slower, since it would attempt the DELETE in

Comment: MySQL Partitioning - can save you or kill you

… single table, where probably only recently read records will be cached, resulting in more disc reads. 2. If you need to delete records from this table, those will be quicker, as they will come out of the partition, not the whole table. 3… on a partitioned table, as Mysql can fire off one thread per partition (at least I have seen this happen in a MyIsam…

Post: How to debug long-running transactions in MySQL

…query log, and examine the log. In MySQL 5.1 and newer with the…some INFORMATION_SCHEMA tables that make this simple. Just query the tables, and if…the disk. #!/bin/bash # Begin by deleting things more than 7 days old find…transaction can possibly have undo log records! The greater moral of this story …

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

table_name | | | use_stopword | 1 | | table_state | 0 | +—————————+———+ 10 rows in set (0.00 sec) mysql> delete

Post: How to recover deleted rows from an InnoDB Tablespace

… need to delete the records of the employee 10008 from the table “salaries”. After the “accidental” deletion of rows you should stop MySQL, take a… directory with some subdirectories inside, one for every single index in the table: ~/recovery-tool# ls pages-1329221407/FIL_PAGE_INDEX/ 0…

Post: MySQL Slow query log in the table

As of MySQL 5.1 get MySQL slow query log logged in mysql.slow_log table instead of the file as you had in previous versions… sort records by physical position quickly without need to have indexes would be quite handy I also should tell log table implementation in MySQL… of in regards to avoiding trouble. For example you can’t ALTER log table while query is running, neither you can delete rows…

Post: Concatenating MyISAM files

… – check record delete-chain – recovering (with sort) MyISAM-table ‘test_concat’ Data records: 3 – Fixing index 1 Data records: 6 And then, back in mysql: mysql> use test Database changed mysql> flush tables; Query…

Post: Using Flexviews - part two, change data capture

… an appropriate name. The Binary Log is the MySQL log which records changes to tables in the database. FlexCDC reads the binary log to… in a moment. Lets create a table, insert some rows, add a change log, delete rows and then insert some more of them: mysql… rows affected (0.00 sec) Records: 2 Duplicates: 0 Warnings: 0 And delete data in a second transaction: mysql> delete from test.demo where c1…