Welcome in Dinesh Patel Blog

BI Concept:  Star Schema: The star schema has a center, represented by a fact table, and the points of the star, represented by the dimension tables. Snowflake Schema: In a snowflake, the dimension tables are normalized. ODS: ODS should be considered only when information retrieval requirements are to be real time and cannot access OLTP systems because of criticality of resources. Dimension Types: Changing Dimension:  Changing dimension is the dimension which has at least one attribute whose value would change over the time. Slowly Changing Dimensions: Attributes of a dimension that would undergo changes over time. For example: Employee work location  • Type I: The existing record is updated with change. • Type II: History is preserved, a new record is added to dimension and old record is marked as inactive.  EndDate or IsLatest is generally used to represent latest record of a business key. • Type III: Type III preserve...

Netezza: ======== Netezza is rows base database using colummar compression Hash algorithm is used S-Blade / Snippet Processing Unit (SPU): ======================================= Blade Server Card and Netezza DB Accelerator (FPGA) 1 Blade Server Card = 8 Core CPU (2 Intel Quad-Core) 1 Blade Server Card = 16 GB DRAM 1 Netezza DB Accelerator = 8 Core FPGA (4x Dual-Core) 1 Snipet Processing Unit = 8 Disks (responsible for) 1 Snipet Processing Unit = 8 Snippet Processor 1 Snippet Processer = 1 Core CPU, 1 Core FPGA and 2 GB DRAM 1 S-Blade = 6 sisks and 2 spare disks Snippet Processing Array (SPA): =============================== 1 Storage Processing Array (SPA) = 4 Disk Encloures 1 Storage Processing Array (SPA) = 2 Spares Disks 1 Disk Encloures = 12 Disks 1 Disk = 1 TB SAS Drive 1 Disk = data on drive call data slice (table are splits across data slides 1 Disk = Devided into three partion - Primary, Mirror and Temp Failed drive is automatically regenerated on a ...