Roundtable August 2020

roundtable@muug.ca

8 participants
5 discussions

How does on get the date function to work in Libre Office spreadsheet?
by eh＠eduardhiebert.com 08 May '23

08 May '23

Hi, I've formatted the cells as date mm/dd/yy and entered the values as is. Also tried by preceeding with equal sign in case deemed to be a formula but neither works. I assume a difference between two days yields the difference in days, correct? Or are the formula different than plain math? Eduard the Osborne guy at last meeting

4 6

Battery replacement service
by Kevin McGregor 31 Aug '20

31 Aug '20

Sorry for off topic posting. Does anyone know of a place where I can get a battery replaced for an early 2015 MacBook Pro? It gets a very low repairability score, and I don’t want to try it myself.

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sshd: Corrupted MAC on input.
by Gilbert E. Detillieux 11 Aug '20

11 Aug '20

I've been getting errors such as the following on one of my systems recently... Jul 29 11:15:33 localhost sshd[26456]: Corrupted MAC on input. Jul 29 11:15:33 localhost sshd[26456]: ssh_dispatch_run_fatal: Connection from 123.123.12.34 port 61436: message authentication code incorrect These tend to happen during large rsync runs, which causes rsync to abort. Following some advice I found on The Google, I tried setting various different values for the "MACs" keyword in sshd_config, but it doesn't seem to change the behaviour. (And, yes, I did remember to restart the sshd service after each config change. Running "ssh -vvv" to the host shows that it's negotiating the new MAC protocol.) What's the likely cause of this? A bad NIC? Bad RAM? (I'm guessing something is corrupting the packets once in a while, but I'm not sure what. If so, it seems to get past TCP's error correcting.) Has anyone else come across this before, and have a suggestion? Thanks, Gilbert -- Gilbert E. Detillieux E-mail: <gedetil(a)cs.umanitoba.ca> Dept. of Computer Science Web: http://www.cs.umanitoba.ca/~gedetil/ University of Manitoba Phone: (204)474-8161 Winnipeg MB CANADA R3T 2N2 Fax: (204)474-7609

6 17

hung mysql transaction locks after a php runtime error?
by Trevor Cordes 01 Aug '20

01 Aug '20

I'm doing a lot with mysql innodb transactions in php these days. I'm wondering, if I start a transaction and use "FOR UPDATE" to lock a bunch of rows (or maybe more critically, the "next auto-insert row"), and then PHP hits a runtime error (say a call to non-existant function), will something in php or mysql (or probably more precisely php's mysqli library) rollback my transaction? Or will my transaction locks stay in place until the next user of that php-fpm thread calls "rollback" or "start transaction"? ... possibly hanging a subsequent web hit if they need the locked rows! (Yes, innodb_lock_wait_timeout in mysql will eventually clear things up, but I'm using the default of 50 to be safe, and I don't want an end user UX to wait 50s for a page load!) I'm using php's default mysqli persistence options, so the connection, while not "pooled", does persist across web page hits (for performance reasons). I'm guessing if I turned off all mysql persistence in php that mysql itself would rollback when it senses the lost connection. However, I'm not sure how much performance I'll lose if php can't use connection persistence? I assume this problem would also exist for other db engines and other hit-based web languages (with persistence). Maybe it's late, but I'm having a hard time coming up with test case that proves what is going on one way or another. However, I could swear that I've already hit the problem and had web hits hang until restarting mysql. In the meantime I'm putting a "rollback" call in my mysql connect function so after (re)connecting to a persistence connection it'll rollback any previous-errored-out-hit leftover garbage. However, with many fpm threads/ps's who knows if the errored-out thread will get a new hit right away!

4 6

PSA - Systems not booting up after installing BootHole patches
by Alberto Abrao 01 Aug '20

01 Aug '20

Originally reported for RedHat/CentOS, seems to affect Ubuntu, Debian and Fedora as well. Can confirm that my Fedora Server did not come back after the update+reboot cycle of today. Debian and Ubuntu servers have the update installed, but are not configured to restart automatically, so they are still working: https://arstechnica.com/gadgets/2020/07/red-hat-and-centos-systems-arent-bo… Kind regards, Alberto Abrao

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Roundtable August 2020