Databases are the long-term memory of enterprises: their content must be ported from one technology generation to the next one. Currently, the database market is « hot » regarding innovations: NoSql, Big Data / Hadoop, key-data databases, in-memory databases, cloud databases, etc. Eranea describes here its solution to migrate existing databases (db2, oracle, etc.) to a new technology in a safe and efficient manner, fully transparent to developers.

1. Solution for
database transformation / migration
1. Introduction
Databases are the long-term memory of
enterprises: their content must be ported from one
technology generation to the next one. Currently,
the database market is « hot » regarding
innovations: NoSql, Big Data / Hadoop, key-data
databases, in-memory databases, cloud databases,
etc. are becoming de facto standards after a period
of stability around the canonical relational
database model materialized by IBM Db2, Oracle
Database, Microsoft Sql Server as dominant
commercial players.
The CIO must carry this « enterprise memory »
from current standard to next one while
maximizing smoothness and invisibility when he
migrates those business data to a new platform. A
safe and riskless approach is key in order to
guarantee business continuity and stable quality
of services for the mission-critical applications.
This task is more complex than it seems because
each database, supposedly respecting the SQL
standard, extends it with additional proprietary
services often used by applications. Moreover, the
SQL standard is not sufficiently precise or is even
incomplete on some specification aspects: it
leaves room for incompatibilities between
implementation in sql requests, data formats, etc.
To satisfy this need for database transformation,
Eranea proposes a solution which is:
• Comprehensive: it covers transformation
of structures (tables, indexes) as well as
transformation of data but also real-time
adaptation of sql access requests to avoid
any impact on application source code.
• Incremental: data migration can happen in
consecutive steps: only one fragment of
the whole database in migrated at a time.
Transactional integrity mechanisms like
the X/Open XA protocol are used to
guarantee, during migration, full integrity
of data splitted between old and new
database management system.
• Transparent: data access requests are
adapted to the syntax of the new database
on the fly to avoid any requested change
on application source code during the
migration. Eranea's transformation engine
will intercept sql requests (select, insert,
update, delete,etc.) and responses in real
time and adapt their format to make
application source code compatible with
the new syntax of the new database
manager and make new answers fully
equivalent to old answers in their structure
and content. So, no change at all is
required on application source code.
• Efficient: the transformation engine
supplied by Eranea concentrates, in one
place, all changes made to sql requests and
data results. The migration is invisible to
application developers who can remain
focused on the implementation of new
business requirements.
• Riskless: the transparency of the switch to
the new system and the incrementality of
this transformation eliminate all risks of
the project in order to guarantee business
continuity.
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2. 2. Objectives
The CIO pursues various objectives when he
takes the decision to migrate databases:
• Cost optimization: Open Source databases
like PostgreSQL have vastly progressed in
the last years. The last 2015 « Magic
Quadrant » from Gartner Group positions
those OSS databases on par - regarding
functions and performances - with
proprietary and commercial systems. But,
the cost advantage for OSS databases
remains unbeatable: their license is free
and their cost may be limited to some very
affordable support contract.
source: Gartner Group 2015
• Rationalization: new application after new
application, diversity, and even
incoherence has emerged in the IT system
of the enterprise through the use of
various database technologies. The CIO
must reorganize this landscape through
unification on an homogeneous platform
in order to put all data under control with
maximum efficiency, in a period where the
volume of this data explodes.
• Flexibility / Agility: the innovation in the
area of database technology is currently
« boiling ». Optimal management and
leverage of corporate data through new
technologies (Big Data / Hadoop, etc.) is
essential to maximize business
competitive advantage. So, data
transformation toward those new
platforms must be fully automated, simple
and efficient.
3. References
Eranea's technology already allowed multiple
database migrations, especially through large-
scale projects aimed at transforming mainframe
(Cobol) or mission critical applications toward
Java/web for cloud computing, core business of
our company.
To mention some among most recent ones:
• Transformation from DB2 to PostgreSQL
for database of the core banking of a large
international private bank: 14'000
relational tables representing 5 terabytes
of data.
• Transformation from DB2 to Sql Server
for an insurance company: 1'500 tables
totaling 500 gigabytes of relational data.
Heavy use of triggers and referential
integrity.
Hence, Eranea's technology is proven and will
allow you to move your data toward a new
platform through a safe and efficient project.
4. Methodology
Eranea applies to data transformation the same
techniques that we practice daily in global system
transformation toward cloud computing:
• Automation: the various steps (example:
database unload / reload) of a database
migration are, by essence, repeated
multiple times during the course of large-
scale migration project. Eranea uses fully
automated tools to analyze and transform
ddl (creation of structures), to unload /
reload data, to analyze and transform dml
(data access). This way, those steps can be
repeated as often and as much as needed
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3. without incurring a cost explosion in
human resources and duration. The
database structure and content as well as
the application can then continue to evolve
without constraint while the migration
project is progressing.
• Incrementality:
◦ The techniques implemented in our
solution allow the database to be
migrated in chunks toward the new
target: data is partitioned into
independent subsets through
automated full-scale activity analysis.
Those subsets can then be migrated
one after the other. Data integrity is
ensured via XA from X/Open.
◦ The switch toward new target database
is initially invisible for the application
until full migration is achieved: the
real-time sql transformation engine
will intercept sql requests, analyze and
reformulate them to reach
compatibility with new system while
preserving strict iso-functionality in
the returned results (data formats,
return codes, etc.) with previous
database system. So, developers won't
suffer any impact during migration.
Only after migration project can they
start implementing, in their reference
source code, the changes done « under
the hood » by the transformation
engine in order to get rid of it.
• Productivity: the entire transformation
happens in a manner totally invisible to
developers and without any freeze of
application maintenance for end-users.
The maximum productivity of all
stakeholders is then fully maintained.
• Safety: fine-grained incrementality and
full transparency of the solution, coupled
to an objective and quantified testing, also
supplied by Eranea, delivers a fully
riskless transformation.
• Transparency: multiple reports produced
by analysis tools deliver very clear and
precise global information as well as full
details on the level of changes executed by
the various components on structures, data
as well as on access requests. It allows, in
particular, the customer to evaluate early
the amount of retro-fitting needed to
remove transformation engine after the
project.
5. Technology
Eranea's solution is mostly composed of
following services:
• A tool to analyze and transform the
containers (ddl: tables, indexes,
referential integrity constraints, triggers,
authorizations, etc.): it guarantees that the
definition of those containers is adapted
to match the requirement of the target
system with a minimum level of changes
when compared to their initial structure.
• A tool to unload / reload data: fully
parallel (= highly multi-threaded), it
allows to handle very large sets of data
with top-level performances. During
reloading, the tool will automatically
adapt data (encoding, structure, etc.) to a
format compatible with new database
system.
• The request transformation engine: based
on various interception techniques
depending on technical context, the
engine will capture the text of the original
sql request as produced by the
application. Then, the integrated sql
analyzer will parse it and regenerate it in
a new format compatible with the target
system. When answers are returned, the
engine will also, as needed, adapt the
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4. format of those answers (data, response
codes) to guarantee full transparency for
the application. This engine can also
operate in passive mode where it only
captures requests and answers to analyze
to details and where it produces metrics
(response time, throughput, etc.)
regarding database activity.
Those cornerstones of our technology are also
equipped with detailed reporting capabilities in
order to obtain very granular details on all
transformations performed to reach compatibity
with new target.
Finally, all the components work in a fully
automated mode in order to be executed
repeatedly as needed at no additional HR cost
during the project and to leverage best DevOps
practices.
6. Project organization
A standard project will usually incur the
following steps:
1. Analysis and execution of structure
(tables, indexes, etc.) transformation to
match constraints of new target (done in a
test environment).
2. Analysis and execution of data unload /
reload (done in a test environment).
3. In parallel with steps above, installation
and activation of interception engine in
passive mode on production systems to
measure and analyze database activity as
well as to evaluate all required
transformations of sql requests.
4. Execution of functional test scenarios
(transactional and batch) as supplied by
customer. Quantification of their relevance
through automated analysis of source code
coverage. Strict and automatic validation
of iso-functionality, request per request,
through comparison of responses obtained
by the application and of changes (directly
through application or indirectly via
referential integrity or triggers) made on
data in the system for an execution on the
old system and an execution on the new
system.
5. Incremental transformation of productive
systems through incremental migration of
independent data subsets, each
independent from each other from a data
integrity standpoint (ACID properties).
During this step, transformation is fully
invisible to application: no change in
source code.
6. Subsequent retro-fitting of needed changes
to match new database system constraints:
sql requests in application source code are
adapted. These adaptations can be done
very quietly and smoothly: as long as the
transformation engine remains in place, he
will transform automatically all sql
requests not yet changed by developers,
who can adapt at their own pace, for
example when they need to work on a
given module for functional
improvements.
In those projects, Eranea can provide, as needed,
additional professional services to train teams to
the new platform and to work as well on the
corresponding evolution of system architecture
(high availability, optimal performances, disaster
recovery, etc.) and the evolution of operations
(administration, data backup / recovery, etc.).
7. Next steps
Your mission-critical databases have to be
migrated smoothly and safely toward a new
system in order to optimize, transform the core IT
systems of your enterprise ?
We are available for any additional question that
you may have or information that you may need.
Drop us a mail: contact@eranea.com.
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