Re: Oracle to Postgres

We did the safe thing, and sized the RDS Postgresql the same as the Linux
system running Oracle 12. Turned out to be massively over-sized.

Your mileage will *certainly* vary, though.

PG12 used a lot less CPU and RAM than PG12.
On Thu, Jul 11, 2024 at 9:45 PM Sam Stearns <sam(dot)stearns(at)dat(dot)com> wrote:

> Thanks for all the advice on the conversion stuff!
>
> For the resource sizing I was chasing more CPU and memory analysis then
> giving recommendations on right-sizing the VM.
>
> On Fri, Jul 12, 2024 at 10:53 AM Ron Johnson <ronljohnsonjr(at)gmail(dot)com>
> wrote:
>
>> On Thu, Jul 11, 2024 at 8:02 PM Sam Stearns <sam(dot)stearns(at)dat(dot)com> wrote:
>>
>>> Howdy,
>>>
>>> We have a project to migrate our Oracle databases that are hosted on an
>>> Oracle Database Appliance to Postgres hosted on a Linux VM. Questions:
>>>
>>>
>>> 1. Is there a tool out there that we can use to analyze resource
>>> sizing on the Appliance that will give resource sizing recommendations for
>>> the VM?
>>>
>>>
>> The appliance doesn't tell you how much space your database uses???
>>
>> Anyway, we converted an 8TB on-prem Oracle 12 db (heavy on CLOBs) to RDS
>> Postgresql 12; the resulting db was about 6TB. I'm sure that vanilla PG
>> would be about the same size (or smaller now, since compression on
>> dupes-allowed b-tree indices is much better now than in PG 12).
>>
>>
>>>
>>> 1. Is there a schema conversion tool or similar out there that we
>>> can use to convert Oracle ==> Postgres?
>>>
>>>
>> As Keith said, Google is your friend.
>>
>> That's how I found ora2pg, which we used in our conversion project (for
>> the data only; someone had to rewrite all the stored procedures).
>>
>> If you use ora2pg, remember to tell it to convert all of the
>> NUMERIC(38,0) columns to BIGINT.
>>
>>>
>
> --
>
> *Samuel Stearns*
> Lead Database Administrator
> *c:* 971 762 6879 | *o:* 503 672 5115 | DAT.com
> [image: DAT]
> <https://www.dat.com/?utm_medium=email&utm_source=DAT_email_signature_link>
>