eivanov89

7 ms·

31.
by eivanov89 7mo ago
Unfortunately, we don't have a proper measurements for IOPOLL mode with and without IOMMU, because initially we didn't configure IOPOLL properly. However, I bet that this mode will be affected as well, because disk still has to wr
32.
by eivanov89 7mo ago
That's a popular DBMS pattern. We chosen writes over reads, because on many NVMe devices writes are faster and it is easier to measure software latency. I guess that in case of sequential I/O result would be similar. However with
33.
by eivanov89 7mo ago
Dear folks, I'm the author of that post. A short summary below. We ran fio benchmarks comparing libaio and io_uring across kernels (5.4 -> 7.0-rc3). The most surprising part wasn’t io_uring gains (~2x), but a ~30% regression caused
34.
Sharded Is Not Distributed: What You Should Know When PostgreSQL Is Not Enough(medium.com)
1 points by eivanov89 1y ago|0 comments
35.
by eivanov89 1y ago
That's indeed interesting, thank you for sharing.
36.
The Surprising gRPC Client Bottleneck in Low-Latency Networks(blog.ydb.tech)
76 points by eivanov89 1y ago|21 comments
37.
Sharded Is Not Distributed: What You Should Know When PostgreSQL Is Not Enough(blog.ydb.tech)
3 points by eivanov89 1y ago|0 comments
38.
by eivanov89 1y ago
To the extent of my knowledge, only forks like YugabyteDB make PostgreSQL truly distributed. Or you should switch to another DB.
39.
by eivanov89 1y ago
Dear friends, I’m the author of this post and I’d love to hear your thoughts and discuss it here.
40.
by eivanov89 2y ago
My post is a secondary research regarding potential issues with weak isolation levels. It includes a link [0] to an in-depth description of what happened to Flexcoin. Additionally, the post references another similar BTC attack [1] that exp
41.
by eivanov89 2y ago
Sorry, might be that the title is a little bit inaccurate. However, the post indeed describes multiple cases, when attackers have stolen many BTC from the exchanges, because of the issue with a weak isolation level. Moreover, one of the exc
42.
Weak isolation levels allowed to steal BTC using plain SQL(blog.ydb.tech)
15 points by eivanov89 2y ago|5 comments
43.
by eivanov89 2y ago
Hi there, I'm the author of the post. I'm happy to answer any questions and appreciate any feedback and experience shared.
44.
by eivanov89 3y ago
I think Denis addressed this in his post: "Overall, as an engineer, you will never regret taking part in the development of a sharding solution. It’s a complex engineering problem with many non-trivial tasks to solve". In other wo
45.
by eivanov89 3y ago
In YDB with block 4+2 erasure coding, you need half the disk space compared to mirror-3-dc schema. Meanwhile CPU usage is just a little bit higher, thus in high throughput tests mirror-3-dc wins. Indeed as mentioned in the post there might
46.
by eivanov89 3y ago
We plan, but currently we are blocked by this issue: https://github.com/yugabyte/tpcc/issues/147 Thus, we consider either waiting for the improvement or trying running DBMSs in containers.
47.
by eivanov89 3y ago
Absolutely. Both CockroachDB and YDB have replication factor equal to 3. So it's similar to Postgres with 2 sync replicas.
48.
by eivanov89 3y ago
Thank you! Any chance you have a list of favourite benchmarks? Now, we are open for suggestions.
49.
by eivanov89 3y ago
Nice to see this link shared on HN. I'm the post author and I'm glad to answer any questions. Also it would be interesting if you share your approach to the benchmarking, when you have to choose between Postgres and any other DB,
50.
by eivanov89 3y ago
That's indeed amusing! I just published a post with title "When Postgres is not enough". It seems that the true distributed databases we have evaluated aren't quite Postgres's cup of tea: https://blog.ydb
51.
An empirical answer to the question, when Postgres is not enough(blog.ydb.tech)
21 points by eivanov89 3y ago|3 comments
52.
When Postgres is not enough: PostgreSQL vs. Distributed DBMSs(blog.ydb.tech)
8 points by eivanov89 3y ago|1 comments
53.
by eivanov89 3y ago
It's really interesting, that Postgres is extremely efficient, but same time can't scale vertically well enough, when there is synchronous replication. Unlike its distributed counterparts.
54.
by eivanov89 3y ago
There're some proofs, check the https://blog.ydb.tech/ for comparison against CockroachDB and YugabyteDB.
55.
by eivanov89 3y ago
Perhaps we'll give HikariCP a chance. However, please keep in mind that the goal of the YDB team is to enhance database performance. We needed virtual threads to make TPC-C efficient enough to generate a reasonable load on a modest amo
56.
by eivanov89 3y ago
Your comparison is indeed thoughtful. I would note a counterexample, though: an expensive restaurant with a very simple description gives no guarantee that you will be delighted, while some inexpensive places (possibly with basic ads) might
57.
by eivanov89 3y ago
I would suggest looking at it from another perspective. Writing a text that precicely describes the image you want might require a lot of effort. Crafting this text to get as close as possible to the imagined picture also requires effort. A
58.
by eivanov89 3y ago
Haha, but quite frankly we had one more in TPC-C for YDB. But unrelated to the virtual threads.
59.
by eivanov89 3y ago
I would like to reply with a quote of sir Tony Hoare's 1980 ACM Turing Award Lecture: "There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies and the other wa
60.
We switched to Java 21 virtual threads and got a deadlock in Postgres TPC-C(blog.ydb.tech)
17 points by eivanov89 3y ago|0 comments

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