Re: Oracle vs SQL Server vs MySQL vs Postgres

From: Powell, Mark <mark.powell2_at_dxc.com>
Date: Thu, 2 Mar 2023 18:55:33 +0000
Message-ID: <CO1PR01MB67090D45CFA2031C1A17A865CEB29_at_CO1PR01MB6709.prod.exchangelabs.com>

SQL Server has row level locking by default however readers block writers and writers block readers. What it does not have by default but you can turn on is row versioning which makes the SQL Server read consistency model work like Oracle's default read consistency model. How row versioning works has been modified in the most recent releases, but I cannot speak to the performance impact the changes provide.

Mark Powell
Database Administration
(313) 592-5148

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From: oracle-l-bounce_at_freelists.org <oracle-l-bounce_at_freelists.org> on behalf of kyle Hailey <kylelf_at_gmail.com> Sent: Wednesday, March 1, 2023 3:54 PM
To: ORACLE-L <Oracle-L_at_freelists.org> Subject: Oracle vs SQL Server vs MySQL vs Postgres

Anyone know of good doc on the comparisons across the major RDMS , like the high level performance OMGs?

Examples

• SQL Server by default is missing row level locking (OMG! of course you can turn it on at a cost)
• Postgres , any open transaction, be it "create table foo(id int); select * from foo; " tanks performance for everyone on the DB doing transactions, everyone.
• Postgres - you wrap your transaction IDs and your database goes down a day or two
• MySQL has similar issue with "create table foo(id int); select * from foo; " where the history length list grows.
• MySQL wait events are worthless. the main wait, like 80% of all waits is a CPU, IO and LOCK all rolled into one, yes indeed, worthless OMG

Kyle

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Received on Thu Mar 02 2023 - 19:55:33 CET