Morgan Tocker

Work: Cash App. Previously: TiDB, MySQL, Vitess.

[Morgan Tocker @morgo]

Great overview + all applies to Spirit too. But also jealous my videos don’t have the same level of visualizations.

Particularly agree on all the caveats about online DDL. It’s very hard to navigate and be successful.

[Holly Guevara @hollylawly]

Ahhh my first video is liveeee! 🙈 I give a demo of how schema changes can lock up your database, how online schema change tools work, and how you can make schema changes without any locking or downtime.

https://t.co/uQOw6ZCcIP

[lefred - @lefredbe.bsky.social @lefred]

If you are a user of gh-ost or pt-online-schema-change, take a look at Spirit! Presented by @morgo during the #MySQLBelgianDays #MySQL #MySQLCommunity

[Morgan Tocker @morgo]

@altmannmarcelo @lefred @stoker @datacharmer I've done one even better: dropped a column instead of an index.

[Ronald Bradford @RonaldBradford]

Fellow Brisbane native @morgo speaking at #MySQLBelgiumDays2024 #MySQLCommunity #mysql https://t.co/QMn6hTMZ09…

[Morgan Tocker @morgo]

@sunbains @mjovanovictech IMHO the explanation of the cache-aside is too simplistic. If you depend on the cache there will be a race (aka stampede) where everyone tries to regenerate the cache at once.

Regenerate it from the DB is nice, but usually in the cache you want to store more complicated objects

[lefred - @lefredbe.bsky.social @lefred]

We are sold-out ! But there is a waiting list, please don't hesitate to subscribe to it if you want to attend we might free some spots next week ! #MySQLBelgianDays #MySQLCommunity 🐬🇧🇪

[Sunny Bains @TiDB @sunbains]

Interesting idea by @morgo

https://t.co/gFXppOxTzV

I think it’s doable but don’t think it’s as simple as taking multiple views from a single transaction. IIRC, handling the deletes makes it tricky.

Perhaps easier to use a transaction per B-tree sub-tree. Once a sub-tree scan completes delete the read view.

[Morgan Tocker @morgo]

@sunbains Yes, apply phase can be tricky:

Gh-ost/spirit implement the "multiple read views" feature already outside the server (autocommit reads), so that part of the FR was not novel.

Gh-ost is single threaded apply. Spirit is multi-threaded only when PK is mem comparable.

[Morgan Tocker @morgo]

@sunbains Think of it as a dirty copy (except uncommitted data) followed by an apply of all deltas

[Morgan Tocker @morgo]

@sunbains It can be multiple transactions. There is no reason it has to be one, it just needs to be RC+. As long as it subscribes and applies changes (delete,insert, update) at the end it will be consistent.

[Giuseppe Maxia @datacharmer]

The end of dbdeployer
#mysql

https://t.co/AjeGKhRW7s

[Morgan Tocker @morgo]

@datacharmer Thank you so much for your work over the years! It has saved me many hours of work.

[Morgan Tocker @morgo]

@sjmudd It is easy for me to add them to CI. Last I checked they were not in dbdeployer's built in download list. That was the only hold up :-)

[Morgan Tocker @morgo]

Part 2 of our MySQL Schema Change story: https://t.co/4GDqdAEaaU (Spirit; a reimplementation of gh-ost)

[Morgan Tocker @morgo]

More Resilient Schema Changes at Scale https://t.co/ubgx7EAVfy (part 1 of 2 in introducing 'Spirit'; our online schema change tool for MySQL).

[Morgan Tocker @morgo]

A much needed improvement.

[lefred - @lefredbe.bsky.social @lefred]

Wim Coekaerts presented the new release model for @MySQL during #MySQL Summit: LTS & Innovation Releases !#MySQLSummit #LevelUp

[Morgan Tocker @morgo]

A fun blog post - some random database feature ideas that are 'keynote worthy' https://t.co/DmZzvieeNv

[Morgan Tocker @morgo]

A TiDB success story (feat. Plan Digests) https://t.co/rgW2dCM5iP

[Morgan Tocker @morgo]

@tobias_petry @Muffins_ @MySQL @mariadb This is likely the result of MySQL cost-model work in ~MySQL 5.7. I think it is relevant because new cost model work is a MariaDB 11 feature. Implementations will likely differ of course.

[Morgan Tocker @morgo]

Blip: A New Open Source MySQL Metrics Collector https://t.co/Vn5vtqgeSS