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Andrey Satarin @asatarin.bsky.social · 26/10/2025

Hades 2? What's your game preferences?

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TigerBeetle @tigerbeetle.com · 18/08/2025

#SD25 online continues today! Join Kyle Kingsbury for Jepsen 18: Serializable Mom How three unconventional systems ensure--or violate--key safety properties 10am PT / 1pm ET / 7pm CET www.youtube.com/watch?v=dpTx... @jepsen.mastodon.jepsen.io.ap.brid.gy

youtube.com

Jepsen 18: Serializable Mom by Kyle Kingsbury

YouTube video by TigerBeetle

Andrey Satarin @asatarin.bsky.social · 14/07/2025

AFAIR circa 10 years ago ApacheCommons (or other popular library) had matcher using reflection to compare two objects. I think it even supported excluding fields, but not nested exclusion.

Andrey Satarin @asatarin.bsky.social · 10/07/2025

Calvin protocol has shards communicate read-write sets and values via messages.

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Hillel @hillelwayne.com · 20/06/2025

------- "Jepsen 18: Serializable Mom", Kyle Kingsbury/@aphyr.com , #sd25 Engineers are tasked with building towers of abstraction, building everything higher and higher above the towering tire fire that is databases. "I professionally set those tires on fire".

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Hillel @hillelwayne.com · 20/06/2025

It's day two of Systems Distributed, hosted by @tigerbeetle.com! I'll be liveskeeting all of the talks, except mine (at 11 AM). Since the venue is a film museum, they're setting up special posters for each talk. #sd25

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Andrey Satarin @asatarin.bsky.social · 20/06/2025

AFAIU very few disaggregated / serverless databases scale to true zero. It’s a pretty special feature

Hillel @hillelwayne.com · 19/06/2025

Reposted by Andrey Satarin

Greetings from #sd25! It's a two-day single-track conference hosted by @tigerbeetle.com. I'll be aiming to liveskeet as many of the talks as I can. Super excited to be here! systemsdistributed.com

systemsdistributed.com

Systems Distributed '25

A conference to teach systems programming and thinking, and how to apply these ideas. All the way across the stack. From systems languages and compilers, to databases and distributed systems.

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Andrey Satarin @asatarin.bsky.social · 19/06/2025

Are these different CPUs? E.g. oversubscribed or something? Should one compare to pure VM costs to see what the premium is for the database?

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Jepsen @jepsen.mastodon.jepsen.io.ap.brid.gy · 06/06/2025

A new #Jepsen report! We worked with TigerBeetle to find seven crashes, elevated latencies during single-node failures, and requests which were retried forever in version 0.16.11. We found only two safety issues: missing results for queries with multiple predicates, and incorrect timestamps in a […]

mastodon.jepsen.io

Original post on mastodon.jepsen.io

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Andrey Satarin @asatarin.bsky.social · 29/05/2025

Notepad++ is awesome. Long time ago it was the only (or one of the few) option to open 1G+ text files on windows. Not sure if still.

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Jepsen @jepsen.mastodon.jepsen.io.ap.brid.gy · 29/04/2025

A small issue in Amazon RDS for PostgreSQL: at the "Repeatable Read” isolation level, which in PostgreSQL normally means Snapshot Isolation, Amazon RDS for PostgreSQL clusters appear to exhibit Long Fork. We observed this behavior in healthy clusters, in versions ranging from 13.15 to 17.4 […]

mastodon.jepsen.io

Original post on mastodon.jepsen.io

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Andrey Satarin @asatarin.bsky.social · 13/01/2025

More on: - reusing corpora of tests from existing systems - metamorphic tests with SQLancer - verifying control plan with fault injection and fuzzing Added to the list asatarin.github.io/testing-distribu…

Curated list of resources on testing distributed systems

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Andrey Satarin @asatarin.bsky.social · 13/01/2025

"Correctness at Feldera" talks about various correctness techniques, including: - machine proof of the underlying DBSP algorithm - differential testing of the implementation www.feldera.com/blog/correctness-at…

feldera.com

Correctness at Feldera

In this blog post, we briefly describe our efforts and development processes that ensure Feldera's engine is correct.

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Andy Pavlo @andypavlo.bsky.social · 01/01/2025

Buckle up because we're banging into the new year with my annual retrospective of the last year in databases! Highlights include license change blowback, Databricks vs. Snowflake gangwar, @duckdb.org's shotgun weddings, and buying a quarterback to impress your lover: www.cs.cmu.edu/~pavlo/blog/...

cs.cmu.edu

Databases in 2024: A Year in Review

Andy rises from the ashes of his dead startup and discusses what happened in 2024 in the database game.

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This is a sample from a list "testing-sql-databases" I have. It's more drafty, most likely missing a ton from big tech, startups and academia alike and not published.

Reposted by Andrey Satarin

Good old Microsoft published some work: - "Deploying a Steered Query Optimizer in Production at Microsoft" dl.acm.org/doi/abs/10.1... - This great talk "The Cascades Framework for Query Optimization at Microsoft" touches on correctness youtu.be/pQe1LQJiXN0

Deploying a Steered Query Optimizer in Production at Microsoft | Proceedings of the 2022 International Conference on Management of Data

You will be notified whenever a record that you have chosen has been cited.

Reposted by Andrey Satarin

Work on correctness of optimizers from Greenplum - "Automatic capture of minimal, portable, and executable bug repros using AMPERe" dl.acm.org/doi/10.1145/... - "Testing the accuracy of query optimizers" dl.acm.org/doi/10.1145/...

Automatic capture of minimal, portable, and executable bug repros using AMPERe | Proceedings of the Fifth International Workshop on Testing Database Systems

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Reposted by Andrey Satarin

Similar work from Databricks: - "SparkFuzz: searching correctness regressions in modern query engines" dl.acm.org/doi/abs/10.1... - "Correctness and Performance of Apache Spark SQL" youtu.be/fddBOZxdUKI

SparkFuzz | Proceedings of the workshop on Testing Database Systems

Reposted by Andrey Satarin

You already mentioned "Snowtrail: Testing with Production Queries on a Cloud Database" from Snowflake dl.acm.org/doi/10.1145/...

Snowtrail | Proceedings of the Workshop on Testing Database Systems

Reposted by Andrey Satarin

MongoDB team did great work on performance: - "Creating a Virtuous Cycle in Performance Testing at MongoDB" dl.acm.org/doi/10.1145/... - "The Use of Change Point Detection ..." dl.acm.org/doi/abs/10.1... - "Fair Benchmarking Considered Difficult" mytherin.github.io/papers/2018-...

Creating a Virtuous Cycle in Performance Testing at MongoDB | Proceedings of the ACM/SPEC International Conference on Performance Engineering

Reposted by Andrey Satarin

Randomized Testing of Cloud Spanner

To counter balance your argument some big tech work on correctness of (SQL) database in a thread below. Spanner has incredibly sophisticated random generated checks internally, this just scratches the surface: - "Randomized Testing of Cloud Spanner" medium.com/@jcorbett_26...

medium.com

One of the secrets behind Cloud Spanner quality is randomized testing. SQL databases like Cloud Spanner have complex APIs. Complete unit…

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Get your point, but to be fair, this list is not targeting correctness of databases (SQL or otherwise). It almost entirely excludes anything single node or targeting single threaded execution (like a fuzzer), with some late additions in asatarin.github.io/testing-dist...

Curated list of resources on testing distributed systems

Alex Miller @alexmillerdb.bsky.social · 12/12/2024

Reposted by Andrey Satarin

I'd be happy to learn that this is just a gap in my testing knowledge, or that there's a bunch of secret testing systems in big companies that I don't know about, but even just skimming the list of asatarin.github.io/testing-dist... kind of illustrates my point. (Thanks again @asatarin.bsky.social!)

Curated list of resources on testing distributed systems

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Alex Miller @alexmillerdb.bsky.social · 12/12/2024

Deterministic simulation has been entirely pushed by startups. Jepsen is jepsen. All the SQL fuzzing stuff I know of comes from academia or database startups. Larger companies seem to only be winning in the application of formal methods (because they can afford to hire a team of ex-professors?)

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Alex Miller @alexmillerdb.bsky.social · 12/12/2024

When I think of advancements in quality and correctness of databases, it feels most things have come from startups or individuals, and not large well-established companies. Which seems... backwards? We talk of startups hacking out code and megacorps crawling to keep a high quality bar.

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This is a sample from a list "testing-sql-databases" I have. It's more drafty, most likely missing a ton from big tech, startups and academia alike and not published.

Deploying a Steered Query Optimizer in Production at Microsoft | Proceedings of the 2022 International Conference on Management of Data

You will be notified whenever a record that you have chosen has been cited.

Automatic capture of minimal, portable, and executable bug repros using AMPERe | Proceedings of the Fifth International Workshop on Testing Database Systems

You will be notified whenever a record that you have chosen has been cited.

SparkFuzz | Proceedings of the workshop on Testing Database Systems

You already mentioned "Snowtrail: Testing with Production Queries on a Cloud Database" from Snowflake dl.acm.org/doi/10.1145/...

Snowtrail | Proceedings of the Workshop on Testing Database Systems

Creating a Virtuous Cycle in Performance Testing at MongoDB | Proceedings of the ACM/SPEC International Conference on Performance Engineering

Randomized Testing of Cloud Spanner

medium.com

One of the secrets behind Cloud Spanner quality is randomized testing. SQL databases like Cloud Spanner have complex APIs. Complete unit…

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Curated list of resources on testing distributed systems

Andrey Satarin @asatarin.bsky.social · 10/12/2024

You should be surprised then. If I recall correctly, @alexmillerdb.bsky.social had (another) rant somewhere about the state of database correctness testing. Generalization is a hard challenge, but there are ways to do it, cough (SQLancer) cough.

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Would give benefit of the doubt and assume they suggest to mock some higher level storage / retrieval API, not the actual DB. This could be useful for unit tests and fast iteration. Agree DBs are too large and non-domain specific surface for mock to be useful or cheap.

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Andrey Satarin @asatarin.bsky.social · 08/12/2024

Google docs (collaborative editing in general)? For sure there is a significant edge part to the system. But saying hardly any datacenter usage is ignoring major part of the system.

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Andy Pavlo @andypavlo.bsky.social · 03/12/2024

Alexey's @clickhouse.com talk here is hilariously off-the-chain. I highly recommend watching it: www.youtube.com/watch?v=jmVx... You can hear me yelling at him from the audience at 1:09, 2:40, and 7:33.

youtube.com

My Database Can Do This by Alexey Milovidov (DBDBD 2024)

YouTube video by DSDSD - Dutch Seminar on Data Systems Design

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Andrey Satarin @asatarin.bsky.social · 27/11/2024

Great. Looking forward to reading.

Andrey Satarin @asatarin.bsky.social · 25/11/2024

Try to use ShellCheck for anything remotely complicated. At the very least have IDE report. The tool definitely knows Bash better than me. $() is what the tool recommends.