January 6, 2019

unreasonable wish -- an sql interface to websites

I was searching Amazon Prime for some Earl Grey tea for my wife. I got these results This was just a basic search for earl grey tea in the Prime Pantry store. I would love to SELECT * FROM products p WHERE p.prime_pantry = 1 AND p.keywords = 'earl grey tea' AND p.packaging = 'bulk' I get that this’ll never happen, but man… it’d be nice.

January 5, 2019

more light, better pictures

We were trying to take some Christmas pictures but feeling a bit unsatisfied with the way the pictures were coming out: I wanted some flash or something, but the batteries on all the “better” cameras were already dead, so I went looking for an alternative. We tried to get the overhead light turned on, but couldn’t find the switch for that. The next-closest source of light was a sheet music lamp on my mom’s piano!

January 4, 2019

watching progress in mysql

Pretty frequently at work, I end up polling a database with some command like SELECT MAX(id) FROM my_tbl; SELECT MAX(id) FROM my_tbl; SELECT MAX(id) FROM my_tbl; SELECT MAX(id) FROM my_tbl; -- .... ad nauseam .... I’ve eventually noticed a few patterns I use pretty consistently: estimate ETA by including NOW()/UNIX_TIMESTAMP() Generally, the point of hovering over the table is to get an estimate of when it will finish/catch up/whatever. For that, you generally want to include a timestamp in the query output, so when you come back a while later, you can know exactly how much time has elapsed.

January 3, 2019

personal finance resources

I wanted to say a tiny bit about personal finance stuff, as I feel like I have gotten a fairly good feel for it. Some great resources to start getting up to speed include: r/personalfinance, especially the common topics the wiki index investments Ideally you want to own a lot of different companies, so you’ve diversified your asset ownership. One of the easiest ways to do this is through index investing, where the index “tracks” a broad swath of the market, like “All S&P 500 Companies” or “All stock market companies”.

January 2, 2019

espps are free money

ESPPs give employees an opportunity to buy the company stock at a discount. In both of the examples I’m aware of, the companies give a 15% discount on the LESSER of the price on the grant date and the price on the purchase date. The purchase dates are every six months, while the grants I’ve seen are either 12 or 24 months. We can analyze this mathematically by breaking it into three cases.

January 1, 2019

tradeoffs

Life is (just) a series of tradeoffs. DawnAnn “Mom” Johnson I heard this so many times growing up that I think I actually stopped hearing it. But recently, I realized that it’s never been more pertinent than to my current day-to-day life as a software engineer. The fundamental tradeoff we make on the Risk Systems team is trading off between how much fraud we catch (and symmetrically, miss!

October 29, 2018

sharded feeds

Suppose that: our humble KV feed sees a lot of traffic. someone needs to consume our KV feed with multiple threads. data The first step is to introduce a notion of “shards” into our data model: ALTER TABLE `kv` ADD COLUMN `shard` INT(11) DEFAULT '0', ADD INDEX `k_fsi_s` (`feed_sync_id`, `shard`); publishing We don’t need to alter the publishing until the publishing itself is too slow to work with a single thread, but this introduces a lot of complications, so let’s just hold off for now.

October 23, 2018

moar stupid jquery tricks

Sometimes it’s useful to use tampermonkey on a site without nice ids for the elements you want to edit. It turns out it’s still pretty easy! Take my own website; I have <h2> elements for the headers, but none of them have any ids associated. But as discussed in the jquery selectors post, we can still select by just the tag, with a selector like $("h2") This returns a jQuery object, which behaves like an array.

October 21, 2018

skydive!

For my 32nd birthday, my wife took me skydiving!

October 17, 2018

killing all timeouts in js

this article has a nice trick for killing all javascript timeouts: function stopAllTimeouts() { var id = window.setTimeout(null, 0); while (id--) { window.clearTimeout(id); } } which can be entered on the javascript console and then run with stopAllTimeouts() This is an effective way to prevent javascript timeouts from doing a whole variety of things, like carousels endless scrolls any other kind of animations