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From: mahamood hussain <hussain.ieg@gmail.com>
Date: Thu, 16 Oct 2025 02:44:26 +0530
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 <CAGc_7HnBQZva+cnnm_=_pWSmrS6v217FPW7b8DC43RKXi9jqvQ@mail.gmail.com>
Subject: Guidance Requested: Migrating Large-Scale DB2 Databases to PostgreSQL
To: Pgsql-admin <pgsql-admin@lists.postgresql.org>
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Hi Team,

We are in the process of migrating several DB2 databases to PostgreSQL,
primarily to reduce the high licensing costs associated with DB2. These
databases support retail applications (e.g., supermarkets and stores), and
during peak hours, we anticipate over 100 concurrent connections.
------------------------------
Current Database Profile:

   -

   Approximately 3,000 tables in total
   -

   Around 100 tables contain active data
   -

   Most tables have low data volume
   -

   A few large tables range from 10 GB to 2 TB
   -

   The largest table contains approximately 80 billion rows

------------------------------
Migration Approach:

   -

   We are using Ispirer for code conversion (DB2 to PostgreSQL).
   -

   For data migration, we are evaluating Fivetran, but noted that it relies
   on the COPY method for data loading.

------------------------------
Questions & Areas Where We Need Guidance:

   1.

   Is Fivetran a suitable option for migrating very large datasets (e.g.,
   tables with 80+ billion rows)?
   2.

   Are there any reliable open-source tools for DB2 to PostgreSQL data
   migration that we can use internally, without needing to invest in a too=
l
   like Fivetran?
   3.

   Are there more scalable or efficient alternatives for both the initial
   load and ongoing/incremental sync to PostgreSQL?

------------------------------
Additional Input Requested:

   -

   What are the key best practices (Do=E2=80=99s and Don=E2=80=99ts) to kee=
p in mind during
   a large-scale DB2 =E2=86=92 PostgreSQL migration?
   -

   Are there specific PostgreSQL settings or configurations we should pay
   attention to for optimizing performance, especially for large datasets a=
nd
   DB2-style workloads?

------------------------------

We are keen to ensure performance, data integrity, and scalability
throughout this migration. Any insights=E2=80=94particularly from those wit=
h
experience in similar large-scale PostgreSQL implementations=E2=80=94would =
be
highly appreciated.

If this is not the right forum for these questions, please do let me know
if there is a better place to seek this guidance.

Thanks in advance for your support!

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<div dir=3D"ltr"><div dir=3D"ltr"><div dir=3D"ltr"><p>Hi Team,</p><p>We are=
 in the process of migrating several DB2 databases to PostgreSQL, primarily=
 to reduce the high licensing costs associated with DB2. These databases su=
pport retail applications (e.g., supermarkets and stores), and during peak =
hours, we anticipate over 100 concurrent connections.</p><hr><h3><span styl=
e=3D"font-weight:normal">Current Database Profile:</span></h3><ul>
<li>
<p>Approximately 3,000 tables in total</p>
</li>
<li>
<p>Around 100 tables contain active data</p>
</li>
<li>
<p>Most tables have low data volume</p>
</li>
<li>
<p>A few large tables range from 10 GB to 2 TB</p>
</li>
<li>
<p>The largest table contains approximately 80 billion rows</p>
</li>
</ul><hr><h3><span style=3D"font-weight:normal">Migration Approach:</span><=
/h3><ul>
<li>
<p>We are using Ispirer for code conversion (DB2 to PostgreSQL).</p>
</li>
<li>
<p>For data migration, we are evaluating Fivetran, but noted that it relies=
 on the <code>COPY</code> method for data loading.</p>
</li>
</ul><hr><h3><span style=3D"font-weight:normal">Questions &amp; Areas Where=
 We Need Guidance:</span></h3><ol>
<li>
<p>Is Fivetran a suitable option for migrating very large datasets (e.g., t=
ables with 80+ billion rows)?</p>
</li>
<li>
<p>Are there any reliable open-source tools for DB2 to PostgreSQL data migr=
ation that we can use internally, without needing to invest in a tool like =
Fivetran?</p>
</li>
<li>
<p>Are there more scalable or efficient alternatives for both the initial l=
oad and ongoing/incremental sync to PostgreSQL?</p>
</li>
</ol><hr><h3><span style=3D"font-weight:normal">Additional Input Requested:=
</span></h3><ul>
<li>
<p>What are the key best practices (Do=E2=80=99s and Don=E2=80=99ts) to kee=
p in mind during a large-scale DB2 =E2=86=92 PostgreSQL migration?</p>
</li>
<li>
<p>Are there specific PostgreSQL settings or configurations we should pay a=
ttention to for optimizing performance, especially for large datasets and D=
B2-style workloads?</p>
</li>
</ul><hr><p>We are keen to ensure performance, data integrity, and scalabil=
ity throughout this migration. Any insights=E2=80=94particularly from those=
 with experience in similar large-scale PostgreSQL implementations=E2=80=94=
would be highly appreciated.</p><p>If this is not the right forum for these=
 questions, please do let me know if there is a better place to seek this g=
uidance.</p><p>


</p><p>Thanks in advance for your support!</p></div></div></div>

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