…another…select count(*) from ontime_fact;” | ./run_query Array ( [count(*)] => 135125787 ) 1…table-size=64M transaction-isolation=READ-COMMITTED user=mysql wait-timeout=86400 To be continued You can now set up a cluster from 1…
Post: Can MySQL temporary tables be made safe for statement-based replication?
May 26, 2008 By 8 Comments
…select * from test.t *************************** 6. row *************************** Log_name: mysql-bin.000011 Pos: 477 Event_type: Query Server_id: 1…TABLE is logged in statement format. But that’s a topic for another…
Post: Review of MySQL 5.6 Defaults Changes
October 8, 2012 By 10 Comments
…a second even from as little … innodb_file_per_table =1 Great! We found…metadata = off Yet another change I actively…MySQL is typically protected by Firewall to begin with. open_files_limit = 5000 strangely enough this is where the smart selection…sort_buffer_size = 256K Good choice for very small sorts…
Post: MySQL: what read_buffer_size value is optimal ?
September 17, 2007 By 25 Comments
…sort performance and today I’ve discovered even read_buffer_size selection…table scans, with 3 runs and averaged results. MySQL 5.1.21-beta was used for tests. mysql> select count(*) from…tables with fragmented rows when IO pattern can be a lot different. The degree of parallelizm is another…
Post: A case for MariaDB's Hash Joins
May 31, 2012 By Leave a Comment
…_table=1 …switch=’mrr_sort_keys=…by MySQL 5.5 is as follows: SELECT s_nationkey, l_shipmode, count(*) FROM supplier INNER JOIN lineitem ON s_suppkey = l_suppkey GROUP BY…table orders in PK order has another benefit that it implies reading the table lineitem in PK order. Hence, these benefits mean MySQL…
Post: Multi Column indexes vs Index Merge
September 19, 2009 By 31 Comments
…selecting about 1% rows from this table which contains about 10M rows. mysql [localhost] {msandbox} (test) > explain select avg(length(val)) from…selective. Now lets do another test. I’ve changed the table…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…1…tables, I’ll paste in mysql> show global variables like ‘%table_size%’; +———————+———–+ | Variable_name | Value | +———————+———–+ | max_heap_table_size | 268435456 | | tmp_table…SELECT id FROM…sorts…by doing another pass through. We may also want to have another…
Post: Improved InnoDB fast index creation
November 6, 2011 By 4 Comments
…SELECT RAND() FROM t; Query OK, 2097152 rows affected (10.11 sec) Records: 2097152 Duplicates: 0 Warnings: 0 mysql> ALTER TABLE…table” part will not be affected by a slow tmpdir, but rebuilding the indexes will obviously take longer. Another…
Post: MySQL-Memcached or NOSQL Tokyo Tyrant - part 1
October 15, 2009 By 16 Comments
…as well? What sort of throughput would we… then compare using MySQL to using MySQL + Memcached, and … from that row to lookup up a row in another table … to a challenge faced by almost everyone how …selects a random # between 1 and 2 Million and looks up the result via that key. It then uses data from…
Post: MySQL Backup tools used by Percona Remote DBA for MySQL
March 13, 2013 By 8 Comments
…some sort of…table (or entire schema) was dropped accidentally Your InnoDB table was corrupt and mysql… from backup is another…TABLES WITH READ LOCK” –compress, compresses tables per file and should typically be enabled by… -> 1 hour…TABLE WITH READ LOCK”. Namely when a select is blocking the flush from…
