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Search - "why did you do this to me cache?"
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I absolutely HATE "web developers" who call you in to fix their FooBar'd mess, yet can't stop themselves from dictating what you should and shouldn't do, especially when they have no idea what they're doing.
So I get called in to a job improving the performance of a Magento site (and let's just say I have no love for Magento for a number of reasons) because this "developer" enabled Redis and expected everything to be lightning fast. Maybe he thought "Redis" was the name of a magical sorcerer living in the server. A master conjurer capable of weaving mystical time-altering spells to inexplicably improve the performance. Who knows?
This guy claims he spent "months" trying to figure out why the website couldn't load faster than 7 seconds at best, and his employer is demanding a resolution so he stops losing conversions. I usually try to avoid Magento because of all the headaches that come with it, but I figured "sure, why not?" I mean, he built the website less than a year ago, so how bad can it really be? Well...let's see how fast you all can facepalm:
1.) The website was built brand new on Magento 1.9.2.4...what? I mean, if this were built a few years back, that would be a different story, but building a fresh Magento website in 2017 in 1.x? I asked him why he did that...his answer absolutely floored me: "because PHP 5.5 was the best choice at the time for speed and performance..." What?!
2.) The ONLY optimization done on the website was Redis cache being enabled. No merged CSS/JS, no use of a CDN, no image optimization, no gzip, no expires rules. Just Redis...
3.) Now to say the website was poorly coded was an understatement. This wasn't the worst coding I've seen, but it was far from acceptable. There was no organization whatsoever. Templates and skin assets are being called from across 12 different locations on the server, making tracking down and finding a snippet to fix downright annoying.
But not only that, the home page itself had 83 custom database queries to load the products on the page. He said this was so he could load products from several different categories and custom tables to show on the page. I asked him why he didn't just call a few join queries, and he had no idea what I was talking about.
4.) Almost every image on the website was a .PNG file, 2000x2000 px and lossless. The home page alone was 22MB just from images.
There were several other issues, but those 4 should be enough to paint a good picture. The client wanted this all done in a week for less than $500. We laughed. But we agreed on the price only because of a long relationship and because they have some referrals they got us in the door with. But we told them it would get done on our time, not theirs. So I copied the website to our server as a test bed and got to work.
After numerous hours of bug fixes, recoding queries, disabling Redis and opting for higher innodb cache (more on that later), image optimization, js/css/html combining, render-unblocking and minification, lazyloading images tweaking Magento to work with PHP7, installing OpCache and setting up basic htaccess optimizations, we smash the loading time down to 1.2 seconds total, and most of that time was for external JavaScript plugins deemed "necessary". Time to First Byte went from a staggering 2.2 seconds to about 45ms. Needless to say, we kicked its ass.
So I show their developer the changes and he's stunned. He says he'll tell the hosting provider create a new server set up to migrate the optimized site over and cut over to, because taking the live website down for maintenance for even an hour or two in the middle of the night is "unacceptable".
So trying to be cool about it, I tell him I'd be happy to configure the server to the exact specifications needed. He says "we can't do that". I look at him confused. "What do you mean we 'can't'?" He tells me that even though this is a dedicated server, the provider doesn't allow any access other than a jailed shell account and cPanel access. What?! This is a company averaging 3 million+ per year in revenue. Why don't they have an IT manager overseeing everything? Apparently for them, they're too cheap for that, so they went with a "managed dedicated server", "managed" apparently meaning "you only get to use it like a shared host".
So after countless phone calls arguing with the hosting provider, they agree to make our changes. Then the client's developer starts getting nasty out of nowhere. He says my optimizations are not acceptable because I'm not using Redis cache, and now the client is threatening to walk away without paying us.
So I guess the overall message from this rant is not so much about the situation, but the developer and countless others like him that are clueless, but try to speak from a position of authority.
If we as developers don't stop challenging each other in a measuring contest and learn to let go when we need help, we can get a lot more done and prevent losing clients. </rant>14 -
3 rants for the price of 1, isn't that a great deal!
1. HP, you braindead fucking morons!!!
So recently I disassembled this HP laptop of mine to unfuck it at the hardware level. Some issues with the hinge that I had to solve. So I had to disassemble not only the bottom of the laptop but also the display panel itself. Turns out that HP - being the certified enganeers they are - made the following fuckups, with probably many more that I didn't even notice yet.
- They used fucking glue to ensure that the bottom of the display frame stays connected to the panel. Cheap solution to what should've been "MAKE A FUCKING DECENT FRAME?!" but a royal pain in the ass to disassemble. Luckily I was careful and didn't damage the panel, but the chance of that happening was most certainly nonzero.
- They connected the ribbon cables for the keyboard in such a way that you have to reach all the way into the spacing between the keyboard and the motherboard to connect the bloody things. And some extra spacing on the ribbon cables to enable servicing with some room for actually connecting the bloody things easily.. as Carlos Mantos would say it - M-m-M, nonoNO!!!
- Oh and let's not forget an old flaw that I noticed ages ago in this turd. The CPU goes straight to 70°C during boot-up but turning on the fan.. again, M-m-M, nonoNO!!! Let's just get the bloody thing to overheat, freeze completely and force the user to power cycle the machine, right? That's gonna be a great way to make them satisfied, RIGHT?! NO MOTHERFUCKERS, AND I WILL DISCONNECT THE DATA LINES OF THIS FUCKING THING TO MAKE IT SPIN ALL THE TIME, AS IT SHOULD!!! Certified fucking braindead abominations of engineers!!!
Oh and not only that, this laptop is outperformed by a Raspberry Pi 3B in performance, thermals, price and product quality.. A FUCKING SINGLE BOARD COMPUTER!!! Isn't that a great joke. Someone here mentioned earlier that HP and Acer seem to have been competing for a long time to make the shittiest products possible, and boy they fucking do. If there's anything that makes both of those shitcompanies remarkable, that'd be it.
2. If I want to conduct a pentest, I don't want to have to relearn the bloody tool!
Recently I did a Burp Suite test to see how the devRant web app logs in, but due to my Burp Suite being the community edition, I couldn't save it. Fucking amazing, thanks PortSwigger! And I couldn't recreate the results anymore due to what I think is a change in the web app. But I'll get back to that later.
So I fired up bettercap (which works at lower network layers and can conduct ARP poisoning and DNS cache poisoning) with the intent to ARP poison my phone and get the results straight from the devRant Android app. I haven't used this tool since around 2017 due to the fact that I kinda lost interest in offensive security. When I fired it up again a few days ago in my PTbox (which is a VM somewhere else on the network) and today again in my newly recovered HP laptop, I noticed that both hosts now have an updated version of bettercap, in which the options completely changed. It's now got different command-line switches and some interactive mode. Needless to say, I have no idea how to use this bloody thing anymore and don't feel like learning it all over again for a single test. Maybe this is why users often dislike changes to the UI, and why some sysadmins refrain from updating their servers? When you have users of any kind, you should at all times honor their installations, give them time to change their individual configurations - tell them that they should! - in other words give them a grace time, and allow for backwards compatibility for as long as feasible.
3. devRant web app!!
As mentioned earlier I tried to scrape the web app's login flow with Burp Suite but every time that I try to log in with its proxy enabled, it doesn't open the login form but instead just makes a GET request to /feed/top/month?login=1 without ever allowing me to actually log in. This happens in both Chromium and Firefox, in Windows and Arch Linux. Clearly this is a change to the web app, and a very undesirable one. Especially considering that the login flow for the API isn't documented anywhere as far as I know.
So, can this update to the web app be rolled back, merged back to an older version of that login flow or can I at least know how I'm supposed to log in to this API in order to be able to start developing my own client?6 -
Our web department was deploying a fairly large sales campaign (equivalent to a ‘Black Friday’ for us), and the day before, at 4:00PM, one of the devs emails us and asks “Hey, just a heads up, the main sales page takes almost 30 seconds to load. Any chance you could find out why? Thanks!”
We click the URL they sent, and sure enough, 30 seconds on the dot.
Our department manager almost fell out of his chair (a few ‘F’ bombs were thrown).
DBAs sit next door, so he shouts…
Mgr: ”Hey, did you know the new sales page is taking 30 seconds to open!?”
DBA: “Yea, but it’s not the database. Are you just now hearing about this? They have had performance problems for over week now. Our traces show it’s something on their end.”
Mgr: “-bleep- no!”
Mgr tries to get a hold of anyone …no one is answering the phone..so he leaves to find someone…anyone with authority.
4:15 he comes back..
Mgr: “-beep- All the web managers were in a meeting. I had to interrupt and ask if they knew about the performance problem.”
Me: “Oh crap. I assume they didn’t know or they wouldn’t be in a meeting.”
Mgr: “-bleep- no! No one knew. Apparently the only ones who knew were the 3 developers and the DBA!”
Me: “Uh…what exactly do they want us to do?”
Mgr: “The –bleep- if I know!”
Me: “Are there any load tests we could use for the staging servers? Maybe it’s only the developer servers.”
DBA: “No, just those 3 developers testing. They could reproduce the slowness on staging, so no need for the load tests.”
Mgr: “Oh my –bleep-ing God!”
4:30 ..one of the vice presidents comes into our area…
VP: “So, do we know what the problem is? John tells me you guys are fixing the problem.”
Mgr: “No, we just heard about the problem half hour ago. DBAs said the database side is fine and the traces look like the bottleneck is on web side of things.”
VP: “Hmm, no, John said the problem is the caching. Aren’t you responsible for that?”
Mgr: “Uh…um…yea, but I don’t think anyone knows what the problem is yet.”
VP: “Well, get the caching problem fixed as soon as possible. Our sales numbers this year hinge on the deployment tomorrow.”
- VP leaves -
Me: “I looked at the cache, it’s fine. Their traffic is barely a blip. How much do you want to bet they have a bug or a mistyped url in their javascript? A consistent 30 second load time is suspiciously indicative of a timeout somewhere.”
Mgr: “I was thinking the same thing. I’ll have networking run a trace.”
4:45 Networking run their trace, and sure enough, there was some relative path of ‘something’ pointing to a local resource not on development, it was waiting/timing out after 30 seconds. Fixed the path and page loaded instantaneously. Network admin walks over..
NetworkAdmin: “We had no idea they were having problems. If they told us last week, we could have identified the issue. Did anyone else think 30 second load time was a bit suspicious?”
4:50 VP walks in (“John” is the web team manager)..
VP: “John said the caching issue is fixed. Great job everyone.”
Mgr: “It wasn’t the caching, it was a mistyped resource or something in a javascript file.”
VP: “But the caching is fixed? Right? John said it was caching. Anyway, great job everyone. We’re going to have a great day tomorrow!”
VP leaves
NetworkAdmin: “Ouch…you feel that?”
Me: “Feel what?”
NetworkAdmin: “That bus John just threw us under.”
Mgr: “Yea, but I think John just saved 3 jobs. Remember that.”4 -
I had spent the last year working on a online store power by woocommerce with over 100k products from various suppliers. This online store utilized a custom API that would take the various formats that suppliers offer their inventory in and made them consistent. Now everything was going swimmingly initially, but then I began adding more and more products using a plug-in called WP all import. I reached around 100k products and the site would take up to an entire minute to load sometimes timing out. I got desperate so I installed several caching plugins, but to no avail this did not help me. The site was originally only supposed to take three to four months but ended up taking an entire year. Then, just yesterday I found out what went wrong and why this woocommerce website with all of these optimizations was still taking anywhere from 60 to 90 seconds to load, or just timing out entirely. I had initially thought that I needed a beefier server so I moved it to a high CPU digitalocean VM. While this did help a little bit, the site was still very slow and now I had very high CPU usage RAM usage and high disk IO. I was seriously stumped the Apache process was using a high amount of CPU and IO along with MYSQL as well. It wasn't until I started digging deeper into the database that I actually found out what the issue was. As I was loading the site I would run 'show process list' in the SQL terminal, I began to notice a very significant load time for one of the tables, so I went to go and check it out. What I did was I ran a select all query on that particular table just to see how full it was and SQL returned a error saying that I had exceeded the maximum packet size. So I was like okay what the fuck...
So I exited my SQL and re-entered it this time with a higher packet size. I ran a query that would count how many rows were in this particular table and the number came out to being in the millions. I was surprised, and what's worse is that this table belong to a plugin that I had attempted to use early in the development process to cache the site. The plugin was deactivated but apparently it had left PHP files within the wp content directory outside of the actual plugin directory, so it's still executing scripts even though the plugin itself was disabled. Basically every time I would change anything on the site, it would recache the whole thing, and it didn't delete any old records. So 100k+ products caching on saves with no garbage collection... You do the math, it's gonna be a heavy ass database. Not only that but it was serialized data, so when it did pull this metric shit ton of spaghetti from the database, PHP then had to deserialize it. Hence the high ass CPU load. I had caching enabled on the MySQL end of things so that ate the ram. I was really desperate to get this thing running.
Honest to God the main reason why this website took so long was because the load times made it miserable to work on. I just thought that the hardware that I had the site on was inadequate. I had initially started the development on a small Linux VM which apparently wasn't enough, which is why I moved it to digitalocean which also seemed to not be enough, so from there I moved to a dedicated server which still didn't seem to be enough. I was probably a few more 60-second wait times or timeouts from recommending a server cluster to my client who I know would not be willing to purchase it. The client who I promised this site to have completed in 3 months and has waited a year. Seriously, I would tell people the struggles that I would go through with this particular site and they would just tell me to just drop the site; just take the money, just take the loss. I refused to, this was really the only thing that was kicking my ass. I present myself as this high-and-mighty developer like I'm just really good at what I do but then I have this WordPress site that's just beating the shit out of me for a year. It was a very big learning experience and it was also very humbling as well, it made me realize that I really don't know as much as I think I might. It was evidence that there is still so much more to learn out there, I did learn a lot from that experience especially about optimizing websites the different types of methods to do that particular lonely on the server side and I'll be able to utilize this knowledge in the future.
I guess the moral of the story is, never really give up. Ultimately things might get so bad that you're running on hopes and dreams. Those experiences are generally the most humbling. Now I can finally present the site that I am basically a year late on to the client who will be so happy that I did not give up on the project entirely. I'll have experienced this feeling of pure euphoria, and help the small business significantly grow their revenue. Helping others is very fulfilling for me, even at my own expense.
Anyways, gonna stop ranting. Running out of characters. If you're still here... Ty for reading :')7 -
Fuck Google Chrome cache.
For almost an hour, sat and tried to make changes to a react UI but unfortunately nothing's changing. Started to worry and doubt myself.
Even thought of getting myself the yellow duck! But fuck no , little did I realise that Chrome "intelligently" fetched my page from cache even though I was using incognito! Had to re-open the browser to realise that.
How did I find out you ask? I thought why not fucking open the same page in Mozilla . Why? Because why not?! But I still can't believe that I wasted a whole fucking hour due to that piece of shit called cache!19