3 ms·

> Let me know if I am still using it wrong. You're not using it wrong, but you are measuring wrong. Check out the filetype of the journal files $ file -bi

> Let me know if I am still using it wrong. You're not using it wrong, but you are measuring wrong. Check out the filetype of the journal files $ file -bi /var/log/journal/1234blahblah/system@foobardedoopdedo.journal application/x-linux-journal; charset=binary Your measurement procedure is wrong because the `journalctl` command is doing something different. It isn't just reading a plain file, it is reading a binary file. On the other hand, `grep` and `rg` are reading straight text. > it seems difficult to believe that journalctl --grep can be faster. Why? It could be doing it in parallel. One thread starts reading at position 0 and reads till N, another starts at N+1 and reads to 2N, etc. That's a much faster read operation. But I'm guessing and have no idea if this is what is actually being done or not. P.S.: I know. As I specified in my earlier comment, I get burned with build artifacts and project logs. Things that most people would have in their .gitignore files but you can sure expect to grep through when debugging.

burntsushi 2y ago
Their measurement isn't wrong. It's demonstrating the exact point in question: that if the logs were just stored in plain text, then grepping them would be an order of magnitude faster (or multiple orders of magnitude in the case of ripgrep) than whatever `journalctl --grep` is doing.
- godelski 2y ago
  Their measurements are wrong because the journalctl command is also performing a decompression operation. THEY ARE NOT DOING THE SAME THING > that if the logs were just stored in plain text So store them in plain text then cat /etc/systemd/journald.conf https://www.freedesktop.org/software/systemd/man/latest/journald.conf.html
  - burntsushi 2y ago
    How it's doing the search is irrelevant. What's being measured here is the user experience. This isn't some kind of attempt to do an apples-to-apples grep comparison. This is about how long you have to wait for a search of your logs to complete.
bombela 2y ago
What matters in this discussion is the outcome. For the exact same logs: journalctl takes 10s to search through 4GiB. And misses most of the matches. (rip)grep takes (0.1)0.5s to search through 605MiB. In other words. journalctl consumes much more space, and a lot more time, to return an order or magnitude less results to the same query. What does journalctl offers, that makes this resource, time and correctness tradeoff worth it?

burntsushi 2y ago

Their measurement isn't wrong. It's demonstrating the exact point in question: that if the logs were just stored in plain text, then grepping them would be an order of magnitude faster (or multiple orders of magnitude in the case of ripgrep) than whatever `journalctl --grep` is doing.

godelski 2y ago
Their measurements are wrong because the journalctl command is also performing a decompression operation. THEY ARE NOT DOING THE SAME THING > that if the logs were just stored in plain text So store them in plain text then cat /etc/systemd/journald.conf https://www.freedesktop.org/software/systemd/man/latest/journald.conf.html
- burntsushi 2y ago
  How it's doing the search is irrelevant. What's being measured here is the user experience. This isn't some kind of attempt to do an apples-to-apples grep comparison. This is about how long you have to wait for a search of your logs to complete.

bombela 2y ago

What matters in this discussion is the outcome. For the exact same logs: journalctl takes 10s to search through 4GiB. And misses most of the matches. (rip)grep takes (0.1)0.5s to search through 605MiB. In other words. journalctl consumes much more space, and a lot more time, to return an order or magnitude less results to the same query. What does journalctl offers, that makes this resource, time and correctness tradeoff worth it?