jerrinot

8 ms·

31.
by jerrinot 3y ago
A QuestDB engineer here: These are cool benchmarks! The idea to try Robin Hood probing came to me after receiving some feedback on Reddit. I ran initial experiments, and the results were promising, leading to its integration into our codeba
32.
Transaction Isolation in Postgres(thenile.dev)
160 points by jerrinot 3y ago|25 comments
33.
by jerrinot 3y ago
What are your requirements? We see some people switching from InfluxDB to QuestDB. Common reasons include SQL support (InfluxDB strategy is a bit confusing here), performance and issues with high-cardinality in InfluxDB. Full Disclosure: I
34.
by jerrinot 3y ago
QuestDB engineer here: It's true that our non-idiomatic Java usage denies us some of the benefits typically associated with Java programming. Automatic memory management and the old "Write Once, Run Anywhere" paradigm are dif
35.
by jerrinot 3y ago
QuestDB engineer here: We use jlink to create images for selected platforms. This means not even JRE is a dependency: You unpack a tarball and you are good to go. See: https://questdb.io/docs/get-started/binaries&#
36.
Leveraging Rust in our Java database(questdb.io)
151 points by jerrinot 3y ago|88 comments
37.
Temporal Fuzzing I: Memory Models (2021)(reitzen.com)
2 points by jerrinot 3y ago|0 comments
38.
by jerrinot 3y ago
I could use DirectByteBuffer instances as CHM values. But Java deallocates the backing memory of DirectByteBuffers during object finalization. If there is no on-heap memory pressure then there is no GC and thus no finalization. So it would
39.
by jerrinot 3y ago
I only learned about the left-right schema after finishing my design. I thought I came up with something novel - it turns out it was just my ignorance:) Still, I think the left-right crate could benefit from one optimization I came up with.
40.
by jerrinot 3y ago
That's actually exactly what I did! I removed this part from the article as I felt it was not relevant for the concurrent protocol design and it was adding mental load for readers not that fluent in Java.
41.
by jerrinot 3y ago
That's indeed a very good question! There are 2 sets of reasons: 1. Technical The contract is given - I'm receiving usernames as CharSequence(String). I could change that, but that would likely require changes in the SQL parser -
42.
by jerrinot 3y ago
Hello, the author here. It feels great to see my blog on HN! It was quite a journey, at first I thought I invented a novel concurrency schema. However, it turns out that it was simply a mix of my ignorance and hubris! :-) Still, I had a lot
43.
by jerrinot 3y ago
DirectByteBuffer exhibits an intriguing behavior: it deallocates its backing memory during the finalization process, which occurs after garbage collection cycles. This poses an issue if your system is conservative with on-heap allocations,
44.
by jerrinot 3y ago
it's the usual spectrum of tests: 1. correctness: from small units tests to relatively complex integrations tests. they typically populate a test database and query it via various interfaces, such as REST or the Postgres protocol. we u
45.
by jerrinot 3y ago
Hello, I'm Jaromir, one of the core engineers at QuestDB team. I just noticed this blog is trending! Andrei - the author - lives in Bulgaria and he is probably already sleeping. Happy to answer any question the blog left unanswered.
46.
The mystery of the shrinking FD limit: A deep dive into JVM file limits(questdb.io)
4 points by jerrinot 3y ago|0 comments
47.
Why Apache Kafka doesn't need fsync to be safe(jack-vanlightly.com)
2 points by jerrinot 3y ago|0 comments
48.
Brain scans can translate a person’s thoughts into words(technologyreview.com)
2 points by jerrinot 3y ago|0 comments
49.
by jerrinot 4y ago
Vanilla Firefox beats it too if you set `privacy.resistFingerprinting` to `true`. I assume Mullvad browsers has this on by default.
50.
by jerrinot 4y ago
Hi, it's the author here. I thoroughly enjoyed my troubleshooting session and thought that others might enjoy it too. How often do you debug the internals of a build tool? Therefore, I wrote this post to share my story and also to expr
51.
Unstable Builds and Open Source Infrastructure(questdb.io)
2 points by jerrinot 4y ago|1 comments
52.
Listen to Your CPU – Full-Table Scans Are Fast(questdb.io)
7 points by jerrinot 4y ago|0 comments
53.
by jerrinot 4y ago
The article is not _just adding an index_. They are embedding one of the search fields in a table _primary key_. That likely means the whole physical table layout is tailored for that single specific query. While it can help to win this ver
54.
LockSupport.parkNanos() Under the Hood and the Curious Case of Parking(hazelcast.com)
2 points by jerrinot 5y ago|0 comments
55.
by jerrinot 6y ago
The truth is the original Hazelcast replication protocol was not a good fit for some data-structures. We took the analysis seriously. I know every project and vendor claims that. Here is what we did in recent years: 1. Re-implemented concu
56.
by jerrinot 6y ago
I didn't know about fully concurrent root scanning, thank you! How does root scanning work wrt to Loom? Are stacks of virtual threads treated as roots? I guess there is no other option?
57.
by jerrinot 6y ago
Modern Garbage Collectors do concurrent scanning. I believe most GC implementations have non-concurrent "initial marking" phase, but that's typically fairly quick. It has to scan roots of your object graph, think stack, JNI,
58.
Processing 10M items / second with gRPC and natural batching(jet-start.sh)
1 points by jerrinot 6y ago|0 comments
59.
Processing 10M queries / second on a single node using Jet and gRPC(jet-start.sh)
5 points by jerrinot 6y ago|0 comments
60.
Tutorial: MySQL Change Data Capture with Debezium and Hazelcast(jet-start.sh)
2 points by jerrinot 6y ago|0 comments

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