The document discusses the challenges of querying a distributed relational database management system (RDBMS), highlighting issues such as aggregation, distinctive values, joins, and sub-queries. It suggests that careful data arrangement across partitions and understanding query nature can help mitigate these challenges. Scalebase provides tools for intelligent data distribution to improve the functionality and scalability of distributed databases.

1. Challenges in Querying a
Distributed Relational Database

2. 2
The Challenges of Querying a Distributed RDBMS
This presentation examines some common
challenges that can occur when querying a
distributed RDBMS.
- Challenges
- Solution

3. Challenges

4. 4
The Challenges of Querying a Distributed RDBMS
A distributed relational database can give your
application unlimited scalability.
However, a number challenges can occur when
querying a distributed RDBMS.
1. Aggregation
2. Distinctive Value
3. Joins
4. Sub-Queries
5. The “Combination”

5. 5
1 - The Aggregation Challenge
• Let’s assume that a company stores the HR data
of several departments across multiple partitions.
• When requesting the average salary of all
employees, all departments must be examined.
• If the average salary is calculated separately on
each partition and later amalgamated with all
other results, the final result will be inaccurate.

6. 6
2 - The Distinctive Values Challenge
• Data entries, such as age or salary, will often repeat
throughout the database.
• Finding identical values across multiple partitions can
skew data analysis and produce false query results.
• When an application requests a list of distinct values,
the data needs to be processed in a way where
repetitions are eliminated from result set.

7. 7
3 - The Joins Challenge
• Ideally, records that exist in different partitions
should be joined after considering all of the query
criteria.
The Sharding Conflict - attempting multiple joins from
records that are situated across various partitions
poses a challenge due to the Sharding Conflict

8. 8
4 - The Sub-Queries Challenge
• Often the result of one query is needed to complete
another query. This brings dependencies and
complexity into the system.
For instance, a query examining all employees with
above average salaries requires a sub-query to
determine the average salary, considering all partitions.
In order to yield correct results, this sub-query has to
be processed independently, and before the parent
query.

9. 9
5 - The “Combination” Challenge
• Any combination of:
• Aggregation
• Distinctive Values
• Joins
• Sub-Query
For example, trying to get an average of the distinctive
values of salary.
In order to accomplish this, we first need to eliminate
repetitions and only then aggregate. It’s impossible to do
both together.

10. Solution

11. 11
Meeting the Challenges
• DBAs need to carefully consider how to arrange data
across multiple partitions in a distributed database.
• Distributing the data with
intelligence about the application,
schema and workloads will help
you avoid many conflicts.
• place data together what is used together
• Cross-partition queries will always exist. Considering the
nature of the queries and the application is key to
creating a functional distributed database.

12. 12
ScaleBase – Your Distributed DDBMS Experts
ScaleBase provides specialized data distribution
technology that resolve a broad range of these
challenges
1. ScaleBase Analysis Genie
• Free, SaaS data distribution policy builder
• A guided analysis of the nature of your data, data
relationships and the functional use of your data
2. ScaleBase Software
• A distributed MySQL database management system

13. 13
ScaleBase Analysis Genie, Free, SaaS
• Determines the best way to
scale out a single MySQL
instance to a distributed
relational database
• Creates the best data
distribution policy for your
specific app by analyzing
your schema and queries
• Ensures relational integrity of MySQL with the scalability of
a modern distributed database architecture
• Automated or Expert mode: provides you visibility and
control over all elements of data distribution policy

14. 14
ScaleBase Software
ScaleBase is a distributed MySQL database management system. It is
optimized for the cloud and deploys in minutes so you can scale out to an
unlimited number of users, data and transactions
Dynamically optimizes workloads and availability by logically distributing
data across public, private and geo-distributed clouds
Contact Us
sales@scalebase.com
or
Download free software
ScaleBase Software
www.scalebase.com/software/

15. 15
Start Using ScaleBase Today
Check out ScaleBase software
On Rackspace
On Amazon
On IBM