Is data import from Oracle table to Postgres table in Ora2pg consecutive or random?

From: duc hiep ha <haduchiep(at)googlemail(dot)com>
To: pgsql-general(at)lists(dot)postgresql(dot)org
Subject: Is data import from Oracle table to Postgres table in Ora2pg consecutive or random?
Date: 2023-09-08 10:19:01
Message-ID: CAM2ukh+iP-bFOm=5YpZQka9uyZ6JHtmnYojPCvCD1Vavv5_kaA@mail.gmail.com
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Hello friends,

I want to migrate a large Oracle table to PostgreSQL, which is
approximately 200GB in size and includes a LOB segment. This table has a
primary key column named "ID," which increments by one unit (similar to a
sequence). During the migration of this large table, sometimes the process
terminates prematurely (due to network issues, etc.). As a result, I have
to restart the import process either from the beginning or by using a WHERE
clause in the ora2pg configuration file to import the remaining data from
where it was previously terminated.

However, I've noticed that the import process in ora2pg doesn't seem to
follow a consecutive order, starting from a small ID number and progressing
to a larger ID number. Instead, it appears to import data randomly from
various rows of the table. This makes it impossible to continue importing
data from the point where it was terminated using a WHERE clause in ora2pg.

My questions are:

- Is it correct that ora2pg imports data from the Oracle table to the
PostgreSQL table randomly and not sequentially from a smaller ID to a
larger ID?
- Or can we add additional parameters to the ora2pg.conf file to control
this process and ensure that the data is imported sequentially, following
the primary key from smallest to largest?
Thank you,
Hans

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