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Franck Pachot 💙 💛
@FranckPachot
I used to explain AWS Aurora as "write as if it is data guard / read as if it is RAC". Really nice to read
@KnownAsMarkus
analysis on on Aurora "The log is the database" architecture. I'll add a few immediate subjective opinions on it👇
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Markus Michalewicz
@KnownAsMarkus
Based on #AlloyDB's and #AmazonAurora's approach, some of us at #Oracle were asked about the usefulness of applying redo in the storage tier. These are some of our thoughts: blogs.oracle.com/maa/post/about /cc @dbinmemory, @ashishray
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Franck Pachot 💙 💛
@FranckPachot
Big difference between AWS Aurora read replicas and Oracle Active Data Guard queries: when you add the cache invalidation arrows onto the Aurora architecture diagram, it quickly looks like a monolithic database spaghetti plate over multiple instances
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Franck Pachot 💙 💛
@FranckPachot
>> the same idea has been picked up by two primarily cloud vendors simultaneously Not really simultaneously. GCP is a follower here. And
@neondatabase
is an open-source newcomer. Same idea of separating compute and storage but different times.
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Franck Pachot 💙 💛
@FranckPachot
>> Both solutions send the WAL directly to the read replicas, which amplifies writes Not really. WAL is sent to storage. 6 mirrors across 3 AZs. This is the write amplification, but for HA with q quorum of 4. Then read replicas on top, plus cache invalidation.
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Franck Pachot 💙 💛
@FranckPachot
Note that this (Aurora & AlloyDB) apply to PostgreSQL with full-row copy on any update and full page logging, on cloud providers where inter-AZ is not free. Oracle has optimized in-place updates, and free inter-AD network cost. Main reason for Aurora was the write cost
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