How Traditional BI Tool
Work:
Every computer has two types of data storage mechanisms – disk
(hard disk) and RAM (Random Access Memory). The traditional disk based
technology the query accesses information from multiple tables stored on a
server’s hard disk.
How does Qlikview
In-memory processing Work:
With in-memory database, all information is initially loaded into
memory. It eliminates the need for optimizing database like creating indexes,
aggregates and designing of cubes and star schemas.
Qlikview uses the compression
algorithms which reduce the size of in-memory data than what would be
needed for hard disks. Users query the data loaded into the system’s memory
thereby avoiding slower database access and performance bottlenecks. QlikView
has an inference engine that maintains associations in the data automatically.
It calculates aggregations on the fly as needed for use by multiple people. It
caches data in memory.
Memory and CPU sizing is very important for QlikView, end user
experience is directly connected to the hardware QlikView is running on. The
main performance factors are data model complexity, amount of unique data, UI
design and concurrent users.
Advantages of Qlikview
In-memory:
With In-memory processing the source
database is queried only once instead of accessing the database every time a
query is run thereby eliminating repetitive processing and reducing the burden
on database servers. By scheduling to populate In-memory database overnight
the database servers can be used for operational purposes during peak hours.
Disadvantages of
Qlikview In-memory:
The
increase in number of users and data volumes the amount of RAM needed also
increases which in turn affects the hardware costs. Because RAM is
comparatively more expensive than disk-based memory,
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