…tables | 0.270664 | 0.295955 | 0.025996 | 0.024996 | 34 | 35 | 2056 | 1488 | 48 | 48 | | 2 | starting | 0.000230 | 0.000192 | 0.000000 | 0.000000 | 0 | 0 | 0 | 0 | 29 | 29 | | 9 | statistics | 0.000130 | 0…
Post: How much space does empty Innodb table take ?
December 16, 2008 By 7 Comments
…OK, 0 rows affected (0.30 sec) Check out files (using Innodb File Per Table) -rw-rw—- 1 mysql mysql…0 kB 1 row in set (0.00 sec) Such table‘s .idb file takes 128K from the start…file_per_table the per table tablespaces are not going …table can cause significant space use overhead if small tables are…
Post: Best kept MySQLDump Secret
March 23, 2012 By 13 Comments
…table once it is dropped, transaction also will see the new table which was created after transaction was started, including table created by ALTER TABLE…mysql> alter table C add i int not null; Query OK, 1 row affected (0.65 sec) Records: 1 Duplicates: 0 Warnings: 0…
Post: Percona XtraDB Cluster - installation and setup webinar follow up Q&A
October 28, 2012 By 4 Comments
… the future. The 0.3 – 0.4 second delay… galera and built-in mysql replication are independent from each … For automatic cluster starting, should it be ok to have in…not part of the presentation then as a comment near the end, is how to start…not xtrabackup itself while holding a lock using FLUSH TABLES…
Post: Derived Tables and Views Performance
August 31, 2006 By 16 Comments
Starting MySQL 4.1, MySQL had support for what is called derived tables, inline views or basically subselects in the from clause. In MySQL 5.0…Tables are still handled by materializing them in the temporary table, furthermore temporary table with no indexes (so you really do not…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 28 Comments
…0.001% Which server is badly tuned? Maybe you’re objecting that you don’t know enough about the servers. OK…before the MySQL world started to come around. There are even… technical terms, counters are surrogate measures. They are not helpful. And…those tables are to you, how big the indexes are on disk…
Post: Can we improve MySQL variable handling ?
February 18, 2012 By 8 Comments
…however this only works well if settings are set in my.cnf as if …-defaults –verbose –help … timed-mutexes FALSE tmp-table-size 16777216 tmpdir /tmp transaction-alloc-…started with) yet there seems not to be a way to read it: mysql> set global sort_buffer_size=DEFAULT; Query OK, 0 rows affected (0…
Post: Profiling MySQL stored routines
January 19, 2009 By 4 Comments
…0 Rows_affected: 0 Rows_read: 1 # QC_Hit: No Full_scan: No Full_join: No Tmp_table: No Tmp_table…MySQL builds since it is part of MySQL community version ever since 5.0.37 (note – not all Percona builds are…mysql> set profiling=1; Query OK, 0 rows affected (0.00 sec) mysql> … could start digging deeper…
Post: Improved InnoDB fast index creation
November 6, 2011 By 4 Comments
…TABLE t MODIFY v VARCHAR(2); Query OK, 4194304 rows affected (36.07 sec) Records: 4194304 Duplicates: 0 Warnings: 0 mysql> SHOW PROFILE; +——————————+———–+ | Status | Duration | +——————————+———–+ | starting | 0…
Post: Faster Point In Time Recovery with LVM2 Snaphots and Binary Logs
February 23, 2012 By 3 Comments
…0.15 sec) mysql> drop table salaries; — Ooops! Query OK, 0 rows affected (0.49 sec) mysql> alter table employees add column age smallint unsigned not null default 0; Query OK…
