…with the client clarified the use case: clients make a mistake and … at a point in time. When running Percona Server, you can …. However, you need to have existing table structures in place. Fortunately, …ENGINE=’InnoDB’; EOF mysql -N -B <<'EOF' > import-ddl.sql SELECT CONCAT(‘ALTER TABLE `’, table…
Post: Percona XtraDB Cluster 5.5.30-23.7.4 for MySQL now available
April 17, 2013 By 2 Comments
…script would hang in case the MySQL server on a …existing temporary table would be replicated when TOI was used in wsrep_OSU_method variable. This bug was fixed for the case when…case CREATE TABLE AS SELECT statement was running in parallel with the DDL statement on the selected table, in some cases…
Post: Implications of Metadata Locking Changes in MySQL 5.5
February 1, 2013 By 9 Comments
… > select * from test_2 order by id; session8 > select * from test_2 order by id; session9 > select …MySQL version < 5.5 as the datastore. There was another interesting case this time with how Active MQ uses MySQL when…TABLE should fail in such a case when the table already exists and there is no …
Post: Helgrinding MySQL with InnoDB for Synchronisation Errors, Fun and Profit
November 24, 2011 By 2 Comments
… anybody is aware of their existence, is very welcome. Enter the…: JOIN::exec() (sql_select.cc:1863) ==9090== by 0x6A7D72: mysql_select(THD*, Item***, TABLE_LIST…variables_hash. Deadlock is possible when one connection issues SHOW …set_waiters above and similar cases. And then Helgrind would …
Post: Upgrading MySQL
January 5, 2010 By 24 Comments
… can run MySQL 5.0 database with MySQL 5.1 with no problems in most cases. When storage type… used application rather than your site which exists in single installation – Wordpress, vBulletin etc. With such…. The tool will run SELECT queries on both new and old MySQL installations and check result set…
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 5 Comments
…for Table Cache Related Allocations There are cases when MySQL will allocate a lot of memory for…_table_size and which also only exist for duration of query execution so … tables (both in memory and not): mysql> select * from information_schema.global_temporary_tables \G *************************** 1…
Post: The case for getting rid of duplicate “sets”
May 17, 2011 By 2 Comments
… it serially. When the relational database was first implemented, write-ahead-logging and other technologies did not exist. This made …set (0.00 sec) mysql> select count(*) from ex1; +———-+ | count(*) | +———-+ | 73027220 | +———-+ 1 row in set (0.00 sec) mysql> select sum(val) from …
Post: Shard-Query turbo charges Infobright community edition (ICE)
May 6, 2011 By 23 Comments
… only 29 air carriers in the table: mysql> select count(*), count(distinct UniqueCarrier) from dim_flightG *************************** 1…-Query is faster in nearly every case. The performance of the queries is … when working with large quantities of data. Shard-Query can be used with existing data…
Post: Recovery deleted ibdata1
August 10, 2012 By 9 Comments
…case when a customer deleted the InnoDB main table space – ibdata1 – and redo logs – ib_logfile*. MySQL…mysql# And restart MySQL: root@localhost:/var/lib/mysql# /etc/init.d/mysql restart After the restart all InnoDB tables are reachable: mysql> select…
Post: Quickly finding unused indexes (and estimating their size)
December 5, 2012 By 2 Comments
…mysql> drop view if exists droppable_indexes; mysql> create view droppable_indexes as select… big in this case with test data): mysql> select * from droppable_indexes; +————–+—————+—————————–+—————+ | table…end of the story when it comes to reclaiming …
