… node within the sibling nodes , lft int unsigned — nested set implementation , rgt int unsigned — nested set implementation , node_type enum(‘identifier’,'constant’,…) — reference to…
Post: Moving Subtrees in Closure Table Hierarchies
February 14, 2011 By 18 Comments
… hierarchical data, such as threaded comments, personnel org charts, or nested bill-of-materials. Sometimes it’s tricky to do this… subtrees can be tricky in both Closure Table and the Nested Sets model. It can be easier with the Adjacency List…
Comment: Moving Subtrees in Closure Table Hierarchies
January 18, 2012 By 18 Comments
… currently researching how a closure tree will compare to a nested set tree for a reasonably sized tree, which led me to…
Comment: Faster MySQL failover with SELECT mirroring
February 1, 2009 By 9 Comments
… don’t see any connection between m-m replication and nested sets, so maybe you have several things you need to think…
Comment: Faster MySQL failover with SELECT mirroring
February 1, 2009 By 9 Comments
Baron. where to read about master-master MySQL replication in details? We ran into problems with master-master replication in case of nested sets storage of hierarchical data.
Post: A case for MariaDB's Hash Joins
May 31, 2012 By Leave a Comment
… is the Classic Hash Join. But its known as Block Nested Loop Hash (BNLH) Join in MariaDB. The Classic Hash Join… not bigger than this value. Hence, the reason I have set join_buffer_space_limit=32M. Benchmark Machine Specs The machine… scanning the right-side table becomes costly in comparison. Block Nested Loop Join would perform better than Hash Join when you…
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 4 Comments
… explain these optimizations. Batched Key Access Traditionally, MySQL always uses Nested Loop Join to join two or more tables. What this… MySQL has only supported one join algorithm and that is Nested Loop Join. MariaDB has introduced a new join algorithm Hash… benchmarking in-memory workload, the InnoDB buffer pool size is set to 6G and the buffer pool was warmed up, so…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 141 Comments
… count(pad) from large; +————+ | count(pad) | +————+ | 31457280 | +————+ 1 row in set (4 min 58.63 sec) mysql> select count(pad) from… hash join or sort merge join – it only can do nested loops method which requires a lot of index lookups which… faster. Avoid joins to large tables Joining of large data sets using nested loops is very expensive. Try to avoid it. Joins…
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
…-length. One reason denormalization is important is that nested-loop joins on large data sets are very expensive. If MySQL supported… Use the smallest data types you can, the simplest character sets you can, and watch out for NULLable columns. Use… to perform well on a data warehousing workload. The nested-loop joins are not all that fast on big joins…
Post: Sharing an auto_increment value across multiple MySQL tables
October 4, 2010 By 9 Comments
… insert does two operations to get the value: UPDATE option2 SET id=@id:=id+1; SELECT @id; So which is better… – auto_commit each statement Option 1 – nest each loop in a transaction Option 2 – nest each loop in a transaction The raw…
