Andrei Matei

126 posts

Andrei Matei

Andrei Matei

@andreimatei1

Co-founder of Data Ex Machina

New York City Katılım Ocak 2010
266 Takip Edilen211 Takipçiler
Andrei Matei retweetledi
Andrew Werner
Andrew Werner@ajwerner·
Ever wanna just know if a line of code is being hit? Or how often? Or from where? In prod!? We've been hard at work making that just a click away with side-eye.io!
English
0
5
21
4.9K
Andrei Matei
Andrei Matei@andreimatei1·
@felixge Rando question - is there any code out there for parsing trace files that allows some degree of random access to different time spans, rather than the reader API in x/exp/trace that reads all events? FWIW, for Side-Eye we turn traces into DuckDB, which works out nice for analysis
English
1
0
2
77
Felix Geisendörfer
Felix Geisendörfer@felixge·
For the past few days, I've been hacking on a new algorithm for analyzing go execution traces. It seemed great, but fell apart on real data because it was O(N²) and I struggled to figure out how to optimize it. This morning the solution came to me. Thank you Santa 🎅🏻🎁🎉!!
English
4
4
69
4.7K
Andrei Matei
Andrei Matei@andreimatei1·
@halvarflake FWIW, CockroachDB is written in Go and cares about what's keeping allocations alive - a question for which there's almost no tooling.
English
0
1
7
1.9K
Halvar Flake
Halvar Flake@halvarflake·
Strange thing about memory profiling in GCed languages vs C++ is: In C++ you care what's eating all your memory, in GCed langs you care more "who is causing all the allocations". Different problems...
English
2
1
25
3.5K
Halvar Flake
Halvar Flake@halvarflake·
Perf nerds: What's everybody's view on continuously profiling operations other than CPU cycles in production? Thinking page faults or IOPS, what else is useful? (Forget user space mem profiling for a moment, diff kettle of fish).
English
13
3
37
10K
Andrei Matei
Andrei Matei@andreimatei1·
@asubiotto I don't really know what I'm talking about. The rationalization for LSMs that I've heard was that Google popularized them because GFS is append-only. Otherwise, in CRDB, the read-amp and write-amp are killing us, and the fact that writers externalize the cost to later compaction.
English
1
0
2
0
Alfonso Subiotto ❄️
Alfonso Subiotto ❄️@asubiotto·
Are fully in-memory LSMs a thing or is there a better option? We'd still like to compact levels to take advantage of com{paction,pression} & reduce memory size. Thinking of the storage engine as an LSM when doing lvled compaction seems intuitive regardless of the backing storage
English
4
1
4
0
Halvar Flake
Halvar Flake@halvarflake·
... about Prodfiler that you are curious about and that you want us to talk about, let me know in replies!
English
6
0
15
0
Halvar Flake
Halvar Flake@halvarflake·
I am happy to announce that @seanhn and me will be giving a talk at re:Invent on the internals of our profiler. We plan on talking about how we do unwinding without frame pointers and symbols, how we deal with the JVM from eBPF and some other stuff. If there is anything ...
English
1
26
144
0
Andrei Matei
Andrei Matei@andreimatei1·
@justinjaffray @brandur After Redpanda, I think SingleStore will be the next big WASM user (and they seem to want to go beyond stored procedures github.com/singlestore-la…). Also, Scylla, Postgres, TiDB and CockroachDB seem to all be experimenting with it. It's definitely coming to a DB near you.
English
0
0
1
0
Brandur
Brandur@brandur·
Put down some thoughts trying to articulate where I've found it appropriate to push logic down to the database in the form of stored procs and triggers. The opacity of the side effects of such isn't great, but it's a useful technique given some restraint. brandur.org/fragments/code…
English
3
0
21
0
Andrei Matei
Andrei Matei@andreimatei1·
@largedatabank @CockroachDB I think you're playing word switcheroo. In an open source context, "freeloading" generally means not contributing back code, not $ (to the extent that it means anything at all). But what we all really want, as you admit, is Amazon's $, not their patches.
English
1
0
1
0
Andrei Matei
Andrei Matei@andreimatei1·
@bradfitz I think you can intercept packets/connections at different layers with BPF and keep track of sequence numbers in a map?
English
0
0
1
0
Brad Fitzpatrick 🌻
Brad Fitzpatrick 🌻@bradfitz·
As root on Linux, can you get latest TCP sequence numbers of open connections? Without pcap. (so no tcpkill) It's not in /proc/net/tcp, which can be read by regular users. Netlink INET_DIAG? Not seeing there either. I missing something?
English
14
3
55
0
James Cowling
James Cowling@jamesacowling·
I've been eating gummy bears my whole life and only just realized that the green ones are strawberry and not "green flavored".
English
3
0
10
0
Andrei Matei
Andrei Matei@andreimatei1·
@justinjaffray You could've started reciting some group theory and explain that the cube is just an application.
English
0
0
0
0