June 18, 2013

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

June 10, 2013 By 3 Comments

…of the situation when the oldest untracked log records are overwritten by the new log data. … the CVE-2012-5627 vulnerability, where an unprivileged MySQL account owner could perform brute-force password …. Bug fixed #1186690. Under very rare circumstances, deleting a zero-size bitmap file at the …

Filed Under: MySQL, Percona Server, Percona Software Tagged With:

Post: MySQL Query Patterns, Optimized - Webinar questions followup

June 3, 2013 By 2 Comments

… on “MySQL Query Patterns, Optimized” for Percona MySQL Webinars.  If you missed it, you can still register to view the recording and my… column, and reinitializing the sequence after making certain insert/update/delete operations.  If you have a dataset that changes infrequently, then…

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Post: Finally. How to verify if all MySQL records were recovered

April 25, 2013 By Leave a Comment

… nearly every recovery case the same question arises: How many MySQL records were recovered and how many were lost. Until now there… number of records the page stores. Obviously it doesn’t count any deleted records. The second method to confirm how many records are in the page is to follow records pointers – and count…

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Comment: MySQL Partitioning - can save you or kill you

April 30, 2013 By 45 Comments

… (within a single connection) anywhere in any ‘free’ variant of MySQL. PARTITIONs are scanned one at a time. (Please provide specific… have rambled on about things as a preface to rebutting “delete records from this table, those will be quicker, as they will… can prune, the delete involves (1) find partition (if partitioned), (2) drill down the BTree, (3) remove one record. PARTITIONing makes very…

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Comment: MySQL Partitioning - can save you or kill you

April 30, 2013 By 45 Comments

… probably only recently read records will be cached, resulting in more disc reads. 2. If you need to delete records from this table…, these could easily be quicker on a partitioned table, as Mysql can fire off one thread per partition (at least I… with the table. Removing partitions is easier and quicker than deleting a few hundred thousand rows… for example, if you need…

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Post: Concatenating MyISAM files

November 19, 2012 By 5 Comments

… 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…) Records: 4 Duplicates: 0 Warnings: 0 mysql> delete from test_concat_part where id = 44; Query OK, 1 row affected (0.00 sec) mysql…’ Data records: 3 – Fixing index 1 myisamchk: error: Couldn’t fix table with quick recovery: Found wrong number of deleted records myisamchk: error…

Filed Under: MySQL

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

February 26, 2013 By 1 Comment

…1 warning (39.73 sec) Records: 0 Duplicates: 0 Warnings: 1 mysql> show warnings; +———+——+————————————————–+ | Level | Code | Message | …mysql> delete from dir_test_innodb LIMIT 200000; Query OK, 200000 rows affected (8.65 sec) mysql…

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Post: How to recover deleted rows from an InnoDB Tablespace

February 20, 2012 By 4 Comments

… recover deleted rows? We’re going to follow the same example as in my previous post so we need to delete the records of the employee 10008 from the table “salaries”. After the “accidental” deletion of rows you should stop MySQL, take… OK, 3 rows affected (0.01 sec) Records: 3 Deleted: 0 Skipped: 0 Warnings: 0 mysql (employees) > select * from salaries where emp_no…

Filed Under: Insight for DBAs, MySQL

Post: Using Flexviews - part two, change data capture

March 25, 2011 By 26 Comments

… like an appropriate name. The Binary Log is the MySQL log which records changes to tables in the database. FlexCDC reads the… rows): mysql> insert into test.demo values (NULL,2),(NULL,3); Query OK, 2 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…

Filed Under: Insight for DBAs, Insight for Developers, MySQL

Post: The case for getting rid of duplicate “sets”

May 17, 2011 By 2 Comments

…; Query OK, 9 rows affected (19.51 sec) Records: 9 Duplicates: 0 Warnings: 0 mysql> select * from ex2; +—–+———-+ | val | count(*) | +—–+———-+ | -10 | 1… delete. There is no index on this table. mysql> delete from data where val=16; Query OK, 1 row affected (3.14 sec) mysql…

Filed Under: MySQL
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