A Change-Data-Capture use-case: designing an evergreen cache

Track

Technologies & Solutions

Date and time

Tuesday, 12. October 2021., 10:50

Room

Hall A

Duration

45'

When one’s app is challenged with poor performances, it’s easy to set up a cache in front of one’s SQL database. It doesn’t fix the root cause (e.g. bad schema design, bad SQL query, etc.) but it gets the job done. If the app is the only component that writes to the underlying database, it’s a no-brainer to update the cache accordingly, so the cache is always up-to-date with the data in the database.Things start to go sour when the app is not the only component writing to the DB. Among other sources of writes, there are batches, other apps (shared databases exist unfortunately), etc. One might think about a couple of ways to keep data in sync i.e. polling the DB every now and then, DB triggers, etc. Unfortunately, they all have issues that make them unreliable and/or fragile.You might have read about Change-Data-Capture before. It’s been described by Martin Kleppmann as turning the database inside out: it means the DB can send change events (SELECT, DELETE and UPDATE) that one can register to. Just opposite to Event Sourcing that aggregates events to produce state, CDC is about getting events out of states. Once CDC is implemented, one can subscribe to its events and update the cache accordingly. However, CDC is quite in its early stage, and implementations are quite specific.In this talk, I’ll describe an easy-to-setup architecture that leverages CDC to have an evergreen cache.

Lecture details

Talk Attendence: Attendance in person
Type: Lecture
Level of difficulty: Detailed
Desirable listeners function: Software Developer or Architect
Group of activity: Technologies & Solutions

About speaker

Organizers

The conference is organized by the Croatian Association of Oracle users & Croatian Java Users Association. 

Like us on Facebook

We post news, photos and other interesting facts on official JavaCro Facebook Page.

Follow us on Twitter

Keep up to date with all the news on Twitter!

Zlatni pokrovitelj

Medijski pokrovitelji