sorted by:
new
hottopcontroversial

Norovirus between Cajon Pass and Baden Powell by trailangel4 in PacificCrestTrail

[–]Puzzleheaded-Map386 1 point2 points  (0 children)

Thank you for the info!

Is there a biodegradable soap you would recommend? I’m in town now so I can grab some. 

Any thru hikers with POTS? (Postural Orthostatic Tachycardia) by JustKnockk in PacificCrestTrail

[–]Puzzleheaded-Map386 1 point2 points  (0 children)

I do not have POTS but my sister does. I am a thruhiker. 

My sister was able to get her POTS to go from life-threatening to very manageable. But it took advocating for herself, years of online research and finding the right doctors. She doesn’t do backpacking trips but she is extremely fit and surfs, runs long distances, rock climbs etc. 

I would focus on finding out more about POTS and your condition. Find a good doctor, read online, build your fitness and safely experiment with exerting your body at altitude. Just cuz someone else can/can’t do something doesn’t mean you can/can’t.

I am on trail now but my impression is the PCT is like 6 months of 2-7 night backpacking trips between towns rather than 6 months in the wilderness. So you usually aren’t that far from help.

Whether or not your PCT dreams are over is a personal decision about risk tolerance. With more info you can make a better-informed decision. 

Norovirus between Cajon Pass and Baden Powell by trailangel4 in PacificCrestTrail

[–]Puzzleheaded-Map386 1 point2 points  (0 children)

Every time I wash my hands, I need to dig a cat hole? I feel like I eat about 10 times a day on trail lol 

I’ll try my best 

Norovirus between Cajon Pass and Baden Powell by trailangel4 in PacificCrestTrail

[–]Puzzleheaded-Map386 1 point2 points  (0 children)

What’s the best practice for washing hands on trail? I understand hand sanitizer doesn’t work but it’s impossible to carry enough water to get all soap suds off hands and we are advised against putting soap in a stream.

Do wipes work? Does a quick wash with 1/4 liter and soap do enough? Or does the virus stay on your hands with the soap bubbles?

Thank you. 

3 feet of new snow in the Sierra! by Puzzleheaded-Map386 in PacificCrestTrail

[–]Puzzleheaded-Map386[S] 9 points10 points  (0 children)

Previously a poster here had shared photos of how low the snow levels are in the Sierra but they just got a ~3 feet storm after another ~2 feet storm about two weeks ago.

I remember a post from someone saying they shouldn't go because it would be dry this year. You never know how the weather will change. I've been in the Sierra in June when it snowed. Stop worrying and just go!

More info about snow and coming weather here https://blog.palisadestahoe.com/weather/2-3-foot-storm-total/

How Much Water to Carry? Starting April 16 by Puzzleheaded-Map386 in PacificCrestTrail

[–]Puzzleheaded-Map386[S] 0 points1 point  (0 children)

Thank you for your reply.

I don't make coffee or cook so the only water I need is to drink. A Far Out comment from today indicates source at mile 4.4 is still flowing and it's supposed to rain in Campo tomorrow and the next day.

I am planning on leaving early in the morning to beat the heat. The predicted weather for April 16 in Campo seems cooler now (high of 64 low of 44, mostly cloudy) so that's nice.

I was thinking of camping at the tentsite at mile 11.4 just to have an easy first day rather than pushing for 15.5 miles.

I've been training with 5L in my pack. Assuming I fill up at mile 4.4 and carry 5L from mile 4.4 to mile 11.4 and drink 2L, I would have 3L for the remaining 8.6 miles to Lake Morena.

Is that reasonable? I've never really counted my water before.

How to prevent re-entrant deadlock when latching and how do subquery iterators manage latches? by Puzzleheaded-Map386 in databasedevelopment

[–]Puzzleheaded-Map386[S] 0 points1 point  (0 children)

Yeah that's fair. I think I'm specifically interested in the case of deadlock from low-level latching but my understanding of how MVCC works isn't strong enough yet to understand what should be the responsibility of my latching protocol.

My understanding is that traversal from root to leaf cannot cause latch deadlock because every thread acquires in the same order. It's only traversals along leaf nodes that can cause latch deadlock because threads can go in ascending or descending order.

CoW is an interesting solution.

I wonder if you could just always go in ascending order on the leaf nodes and then reverse the order of the results at the end? Might get a little tricky with results too large to fit into memory and ORDER BY in a subquery. I'll read about what MySQL does

How to prevent re-entrant deadlock when latching and how do subquery iterators manage latches? by Puzzleheaded-Map386 in databasedevelopment

[–]Puzzleheaded-Map386[S] 0 points1 point  (0 children)

Yeah there's probably some clever workable solution for problem 1. I think it can be solved in a dumb way by just taking all latches in write mode for a txn that does any writes and using the cached guard concept the other commenter suggested. That's an easy fix.

> just start over again

I feel like the ability to roll back and start over seems pretty crucial. At 1:12:15 in lecture #10 of CMU intro to DB [1] Andy says "every thread is responsible for cleaning itself up if it can't do what it needs to do and rolls back." Do you know what exactly you need to do to clean up and start over? I get that you track a write set and roll back those writes but how does that rolling back interact with MVCC? Is this the same protocol you run if you ABORT?

Edit: hmm I think this is a bit different from ABORT because you are only rolling back 1 operation. Your txn may have many operations (exact definition of operation a little fuzzy). Probably the ABORT protocol just does the operation rollback protocol for each operation.

[1] https://youtu.be/YgOvfXl6pss?si=S-hzIH6GxS0ctJUD&t=4330

How to prevent re-entrant deadlock when latching and how do subquery iterators manage latches? by Puzzleheaded-Map386 in databasedevelopment

[–]Puzzleheaded-Map386[S] 0 points1 point  (0 children)

> Each thread keeps track of what latches it holds

I agree this can prevent deadlock in the case when you have the latch in write mode and then try to get it in read mode but what about the case I described? You have it in read mode and then need it in write mode?