log4j ?

Dec. 24th, 2021 01:04 pm
malyj_gorgan: (Default)
[personal profile] malyj_gorgan
Слухайте, а хтось може в парі абзаців пояснити, що то таке сабж і з чим його їдят? Дідько з нею, з його vulterability'ею, я хочу зрозуміти, чим був такий хороший чи зручний чи потрібний сам log4j, що та вульнерабіліті виявилася такою проблємною? Тільки пояснити так, на хлопский розум, без відсилань в непотрібні абревіатури.
Дякую!

Date: 2021-12-26 12:33 am (UTC)
From: [personal profile] sassa_nf
чудово.

остання проблема, в діагностиці якої я приймав участь - all the threads are waiting on connection pool. Everyone is tormenting the DB connection pool team to get them to make connection pool more efficient. Looking at the heap dump it became clear there are no connection at all, and it is not about efficiency of borrowing connections. What then? Digging through the logs we see login timeouts during connection establishment. Looking at the flight recordings for the said time, we see the connection getting closed, but we do not see long IO operation causing the timeout. What then?

Well...looking at the flight recordings, we see CPU spiked for minutes, and we see almost all of it is spent on DH key negotiation - during DB connection establishment. Why does it take minutes? Because it switched from compiled and optimised to interpreted mode. So the fix is in working out why it switched to interpreted mode all of a sudden.

I don't know how many production issues caused by NPEs and the absence of monads were fixed without me lending a hand. But I get a feeling that stuff just breaks.

Date: 2021-12-26 01:04 am (UTC)
juan_gandhi: (Default)
From: [personal profile] juan_gandhi

You are pointing at a typical issue that has been driving me nuts for years. Not at that company where we had monads and no NPE, but at all other companies.

Date: 2021-12-26 02:42 am (UTC)
From: [personal profile] sassa_nf
I suppose you mean connection pooling. Unfortunately this is a resource sharing question. Tracking lifetimes becomes unavoidable. Additionally, connections consume resources on two ends, so you can't assume that both ends are going to be fine if you create a connection any time you like: for you it may be 1 a second; for them it may be 1000 a second.

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