Message-ID: <461e3601-24f1-d8e8-da5d-3e5de1ae45c1@enterprisedb.com>
Date: Tue, 12 Apr 2022 17:06:38 +0200
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Subject: Re: Performance for SQL queries on Azure PostgreSQL PaaS instance
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To: Frits Jalvingh <jal@etc.to>, "Kumar, Mukesh" <mkumar@peabodyenergy.com>
Cc: "pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>,
 MUKESH KUMAR <mukesh.kumar14@tcs.com>
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From: Tomas Vondra <tomas.vondra@enterprisedb.com>
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On 4/12/22 16:23, Frits Jalvingh wrote:
> You might be comparing apples and pears..
> 
> Your Oracle is running on prem while Postgres is running on Azure. Azure
> does not really have disks; it seems to have just a bunch of old people
> writing the data on paper - I/O on Azure is ridiculously slow. What
> disks/hardware does the on-prem Oracle have?
> 

Right. It'd be good to do some basic system benchmarks first, e.g. using
"fio" or similar tools, before comparing query timings. It's quite
possible this is due to Azure storage being slower than physical drives
in the on-premise system.

If that does not explain this, I suggest picking a single query and
focus on it, instead of investigating all queries at once. There's a
nice wiki page explaining what info to provide:

https://wiki.postgresql.org/wiki/Slow_Query_Questions


regards

-- 
Tomas Vondra
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company