Postgres System Columns Explained (ctid, xmin,xmax)

Рет қаралды 9,228

Күн бұрын

In this video I explain the difference between ctid,xmin and xmax columns in postgres with repeatable read and read committed.
0:00 Intro
2:00 ctid tuple id
7:00 xmin (minimum transaction id) with read committed
8:00 xmin with read committed
13:00 xmin with repeatable read
19:00 xmax (maximum transaction id)
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Пікірлер: 19

@hnasr Жыл бұрын

Fundamentals of Database Engineering course database.husseinnasser.com

@sagepages9504 Жыл бұрын

Another great video. Would love to see a backend dive into Auth0's private cloud platform!

@diwakarparajuli12 Жыл бұрын

Beautifully explained .. one of the best videos I have seen in a long time.. Thanks man!

@JohnZakaria Жыл бұрын

I have always been reading about isolation levels, tombstones but never have I ever seen them in action. Thank you for Video!

@lakhveerchahal Жыл бұрын

Fascinating stuff! I also recently discovered these columns and pg_stat_user_tables and now very happy to see your video on the same! I guess we were reading the same stuff 😄 Some relevant stuff around this to read would be: - Fillfactor (how it affects ctid) - HOT updates (because postgres always does INSERT operation because of MVCC reasons, it also needs to update the reference pointers in indexes which are pointing to dead tuples, there is definitely cost associated to it but postgres has a smart way to reduce it using HOT chaining) Thanks for the great video Hussein!!

@lakhveerchahal Жыл бұрын

From all this, the takeaway for me was to avoid UPDATE heavy workflows as much as possible.

@lakhveerchahal Жыл бұрын

Amazing video

@krishnaMurari48 Жыл бұрын

excellent video

@blank001 Жыл бұрын

Your content is amazing, I always learn something new ever time I open your videos, if possible can you provide a documentation link or some kind of written article link, I am thinking of making notes of your content, and having a quick access which I can search through.

@priyaghosh5406 Жыл бұрын

nice video

@user-vp1qk6fz5b Жыл бұрын

Great stuff. I think this is too advanced for me, can you please provide real life scenarios where I can benefit from this?

@lautarojayat7914 Жыл бұрын

Excelent

@darpanmalhotra2 Жыл бұрын

Waiting for another video on Repeatable Read v/s Serializable.

@ayuobmousa6589 Жыл бұрын

GOLD

@PiroCoder Жыл бұрын

@Adi-yi6qq 8 ай бұрын

Hi Hussein! If ctid returns the page & slot number of the row on disk then how come running ctid on multiple tables (in postgres) gives same set of (page_id, slot_id) in output? I tried for 3-4 tables and I see a lot of common ctid among them.

@streetfashiontv9149 Жыл бұрын

Does anyone know how to access a postgre SQL database from another computer (windows) other than local Host (loop back 127.10 etc). I have tried modifying the config file but still no connection. I want to be able to log onto another windows computer and open a database application that I packed into a jar using launch4j?