Data warehousing with MySQL MySQL MS-SQL Oracle MySQL DB2 Flat Files Free and Open Source Software MySQL is licensed under GPL. The GPL is a Free and Open Source Software (FOSS) license that grants licensees many rights to the software under the condition that, if they choose to share the software, or software built with GPLlicensed software, they share it under the same liberal terms. Free and Open Source Software Advantages of Open Source •MySQL has 5 million plus active installation base. •New releases immediately downloaded by users providing early feedback on bugs and features. •Access to source code •Write your own features/proprietary Storage Engine •Freedom ! Data Warehousing application Data Warehouse is a relational database. It is designed for query and analysis rather than for transaction processing. It enables an organization to consolidate data from several resources. Extraction ,Transformation and Loading Data Source Staging Tables MERGE & BULK INSERT MERGE Tables Indexes, Memory Views, Summary SWH AWH HEAP Extract Load Transform Storage Performance OLTP/ BI Users Extraction ,Transformation and Loading • • • • • • • Staging database “LOAD DATA INFILE ….” Command. Merging of SQLs Segregating Informations View enhancements Index Enhancement Memory Manipulation Extraction, Transformation and Loading Staging Area and its benefits Relational Table structures are flattened to support extract processes in Staging Area. • First data is loaded into the temporary table and then to the main DB tables. • Reduces the required space during ETL. • Data can be distributed to any number of data marts Partitioning and Storage Engine The MERGE Table MERGE SALES Table • A collection of identical MyISAM tables used as one • You can use SELECT, DELETE, UPDATE, and INSERT on the collection of tables. • Use it when having large tables • DROP the MERGE table, you drop only the MERGE spec. • Advantage : manageability and performance Sales for Yr’04 Aug’04 Oct’04 Sep’04 Partitioning and Storage Engine MERGING based on month as Range JUN2004 JUL2004 JUN2004 OCT2004 AUG2004 SEP2004 OCT2004 Partitioning and Storage Engine MERGE Table Example mysql> CREATE TABLE jan04 ( -> a INT NOT NULL AUTO_INCREMENT PRIMARY KEY, -> message CHAR(20)); mysql> CREATE TABLE feb04 ( -> a INT NOT NULL AUTO_INCREMENT PRIMARY KEY, -> message CHAR(20)); mysql> CREATE TABLE year04 ( -> a INT NOT NULL AUTO_INCREMENT, -> message CHAR(20), INDEX(a)) -> TYPE=MERGE UNION=(jan04,feb04) INSERT_METHOD=LAST; Partitioning and Storage Engine MyISAM Storage Engine • Supports MERGE table. • Support fulltext indexing • “INSERT DELAYED ...” option very useful when clients can't wait for the INSERT to complete. Many client bundled together and written in one block • Compress MyISAM tables with “myisampack” to take up much less space. • Benefit from higher performance on SELECT statements Partitioning and Storage Engine Restrictions on MERGE tables • You can use only identical MyISAM tables for a MERGE table. • MERGE tables use more file descriptors. If 10 clients are using a MERGE table that maps to 10 tables, the server uses (10*10) + 10 file descriptors. • Key reads are slower. When you read a key, the MERGE storage engine needs to issue a read on all underlying tables to check which one most closely matches the given key. Partitioning and Storage Engine • my.cnf parameters for DWH (example) key_buffer = 1G • myisam_sort_buffer_size = 256M • sort_buffer = 5M • query_cache_type = 1 • query_cache_size = 100M key_buffer is the important one, this tells mysql how much memory to cap itself Business Intelligence Using MySQL database server • Drastically reduce information retrieval by distributing data into replicated clusters. This enables parallel processing. • Tighter storage format (3 TB squeezed to 1TB) • Aggregate huge amount of data and deliver reports for OLAP • Relieve overloaded OLTP databases • Availability, scalability and throughput for the most demanding applications, and of course affordability Summary • • • • • • Free and Open Source under GPL MyISAM Storage Engine No Transactional Overhead MERGE Table Tighter storage format Highly efficient