Strikr case on Oracle to PostgreSQL migration (with some amount of information about MariaDB)

1. StrikrSystemsLLP
Oracle to
Strikr case on Database Migration

2. StrikrSystemsLLP
What tools were used
●
A variety of "freeware" tools were investigated
such as
– MyOraDump
– SQLines
– Ora2Pg
– ESF DB migration
●
On multiple Oracle databases of varying sizes
starting from 10Mb to 80Gb (spanning control
experiment db to real-life DB)

3. StrikrSystemsLLP
What was the goal
●
Within the context of the schema, the focus was high fidelity migration
of
– Schema
– Tablespace
– Identifier name(s)
– Table
– Views
– Stored procedures
– User-defined functions
– Triggers
– Index
– Constraints

4. StrikrSystemsLLP
What went well
●
Dump of data from Oracle in CSV format was
obtained
●
The following objects were migrated
– Table
– View
– Index, but no other database object.

5. StrikrSystemsLLP
Challenges faced
●
Stored procedures, user-defined function have
not migrated at all.
●
The storage size of data types of the column(s)
changed across both PostgreSQL and MariaDB
●

6. StrikrSystemsLLP
utf8mb4
●
utf8mb4 is a 4-byte UTF-8 encoding used in Oracle, where as MariaDB
and PostgreSQL use utf8 encoding.
●
tuned tool settings to utilize variable length encoding
●
Encoding expands the storage used by the table(s) and
– impacts 65535 bytes row restriction
– impacts 3072 bytes index key-size restriction.
●
post multiple customization's, the following object(s) were successfully
migrated
– Schema
– Table
– View
– Index (partial)

7. StrikrSystemsLLP
Stored Procedures
CREATE OR REPLACE FUNCTION
cs_fmt_browser_version(
v_name varchar2,
v_version varchar2
)
RETURN varchar2 IS
BEGIN
IF v_version IS NULL THEN
RETURN v_name;
END IF;
RETURN v_name || '/' || v_version;
END;
/
show errors;
CREATE OR REPLACE FUNCTION
cs_fmt_browser_version(
v_name varchar,
v_version varchar
)
RETURNS varchar AS $$
BEGIN
IF v_version IS NULL THEN
RETURN v_name;
END IF;
RETURN v_name || '/' || v_version;
END;
$$ LANGUAGE plpgsql;
plPERL, plPython, plJava
PostgreSQLOracle

8. StrikrSystemsLLP
Stored procedures
●
Unless the migration tool can successfully
parse the SQL grammar for Oracle functions
and navigate compiled object representations
(ie. stored procedures) and also understand
how to map it to the grammar of target
PostgreSQL, the migration of procedures,
functions would not happen as is

9. StrikrSystemsLLP
Way forward
●
We strongly recommend using PostgreSQL for all new application and service initiatives.
●
We must use this opportunity to refactor existing application database(s) prior to migration to
PostgreSQL or MariaDB.
●
However, this effort should be split across two parallel efforts
– consistent correct and verified data dump
– strict SQL standard compliant DDL usage
●
We would also recommend that application teams implement business logic inside application
server and not push it inside the database under the pretext of performance.
●
In the context of PostgreSQL, a strategic decision should be taken regarding which language
would be used for writing pgSQL functions aka user-defined functions ie. PERL, Python, Java
or some other language.

10. StrikrSystemsLLP
Thanks for your time
Thanks for viewing Strikr case study
on Oracle to PostgreSQL and
MariaDB migration.
Engineering
Ragini Jain
Saifi Khan
94 80 87 33 52
hello@strikr.in