…is a single row (well, the PRIMARY KEY index entry for that row). This means typically on…modified cluster-wide is once per RTT. What about WAN clusters? Callaghan’s law applies to WAN clusters as well…to define the relationship between them. When someone joins a group, you run a transaction that …
Post: Percona XtraDB Cluster: Failure Scenarios with only 2 nodes
July 25, 2012 By 6 Comments
…index_size | 2 | | wsrep_cluster_conf_id | 18446744073709551615 | | wsrep_cluster_size | 1 | | wsrep_cluster_state_uuid | 8dccca9f-d4b8-11e1-0800-344f6b618448 | | wsrep_cluster…2491595e99bb, 86928728-d56d-11e1-0800-f7c4916d8330, } joined { 7e6d285b-d56d-11e1-0800-2491595e99bb, } left { } partitioned …
Comment: Database problems in MySQL/PHP Applications
August 11, 2006 By 13 Comments
… disagree with you on this completely because InnoDB uses a clustered index based on (in order) the primary key you specify (an…=1) Ouch! Use INNER JOIN for this instead because it allows the optimizer to use the indexes to join rows together, potentially preventing a table scan. The trick is to know what kind of JOIN to use…
Post: MySQL Indexing Best Practices: Webinar Questions Followup
August 16, 2012 By 4 Comments
… you’re looking for a lot. This will cause data clustering done by these columns which can be helpful if you…. Table2 joins to table1 using Table1′s primary key. Should table2 have an index on the field that is used to join the… need an index on a field which is used to join tables in table2 Q: In regards to extending an index being better…
Post: Percona XtraDB Cluster reference architecture with HaProxy
June 20, 2012 By 63 Comments
… point to a node in the cluster which is already up, so it will join the cluster. The server_id and wsrep_node…] WSREP: New cluster view: global state: 77c9da88-b965-11e1-0800-ea53b7b12451:97, view# 18: Primary, number of nodes: 3, my index: 0… you have a 3 node cluster. mysql> show global status like ‘wsrep_cluster_size’; +——————–+——-+ | Variable_name | Value | +——————–+——-+ | wsrep_cluster_size | 3 | +——————–+——-+ 1 row…
Post: Join performance of MyISAM and Innodb
May 29, 2006 By 6 Comments
… primary key joins are very fast as data is clustered together with index and generally highly optimized Innodb builds hash indexes which helps to speed up lookup by indexes by passing BTREE index…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 19 Comments
… can’t wait for ability to create physically sorted indexes with Innodb (with index built by sort) this is when this should… a single extent. For big tables, a secondary index reserves different extents from the clustered index. Q4: Does Innodb ever merges sequential pages… denormalized database (for example, if ORDER and ORDERLINE tables are joined to form a single table), it might make sense for…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 141 Comments
… referenced by indexes also could be located sequentially or require radom IO if index ranges are scanned. There are also clustered keys in Innodb which combine index access with data access… reduce the gap but I doubt it will be closed. Joins Joins are used to compose the complex object which was previously…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…_row_length: 241 Data_length: 1616904192 Max_data_length: 0 Index_length: 539279360 Data_free: 4194304 Auto_increment: NULL Create_time… joins and other background operations. This will have a direct impact in our query response times and throughput. Setting up a cluster… 1 (assuming a 20 node cluster): cd shard-query ./start_workers 80 I normally start (2 * TOTAL_CLUSTER_CORES) workers. That is…
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
…does this have to do with InnoDB? Data clustering. InnoDB’s primary keys define the physical order… can we improve here? Especially assuming that there are indexes other than the primary key, we can shrink…workload. The nested-loop joins are not all that fast on big joins; the query optimizer can…
