What is journal table in Teradata?
Journal tables are assigned PERM space and they reside in same database as of parent or they can reside on different database. They are mainly used for protection of data and sometimes also for disaster recovery ( fallback is better in this case )
What is scalability in Teradata?
A more precise definition of scalability is familiar to users of the Teradata Database: > Expansion of processing power leads to proportional performance increases. > Overall throughput is sustained while adding additional users. > Data growth has a predictable impact on query times.
What is execute parallel in Teradata?
Parallel execution is usually enabled in Teradata by hash-partitioning the data across all the AMPs defined in the system. Once data is assigned to an AMP, the AMP provides all the database services on its allocation of data blocks.
What is permanent Journal?
Permanent journals are continuously monitoring tables changes, tracking all UPDATE, INSERT and DELETE statements; They are protecting us from data losses by logging changes until the journal tables are manually dropped (pausing the usage of journaling is possible as well).
Which component operates on data in Teradata?
Access Module Processor (AMP) − AMPs, called as Virtual Processors (vprocs) are the one that actually stores and retrieves the data. AMPs receive the data and execution plan from Parsing Engine, performs any data type conversion, aggregation, filter, sorting and stores the data in the disks associated with them.
Which component is part of Teradata’s open architecture?
The main components of Teradata architecture is PE (Parsing Engine), AMP (Access Module Processor) and BYNET . We look into these components in details after looking the logical view of the architecture.
How do I run multiple SQL statements in Teradata?
To allow multiple queries
- Select Tools > Options and select the General tab.
- Choose one or both of the following options: Allow connections to multiple data sources (Query window) Allow multiple queries per connection (Tabs in the Query window)
How do I run a SQL query in parallel?
To achieve parallelism for SQL DML statements, you must first enable parallel DML in your session: ALTER SESSION ENABLE PARALLEL DML; Then any DML issued against a table with a parallel attribute will occur in parallel, if no PDML restrictions are violated.
What is fallback and no fallback in Teradata?
Fallback. Fallback protects the table data by storing the second copy of rows of a table on another AMP called as Fallback AMP. If one AMP fails, then the fallback rows are accessed. With this, even if one AMP fails, data is still available through fallback AMP.