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▲ 100M-Row Challenge with PHP(github.com)
157 points by brentroose 10 hours ago | 77 comments
▲brentroose 10 hours ago | parent | next [-]

A month ago, I went on a performance quest trying to optimize a PHP script that took 5 days to run. Together with the help of many talented developers, I eventually got it to run in under 30 seconds. This optimization process with so much fun, and so many people pitched in with their ideas; so I eventually decided I wanted to do something more.

That's why I built a performance challenge for the PHP community

The goal of this challenge is to parse 100 million rows of data with PHP, as efficiently as possible. The challenge will run for about two weeks, and at the end there are some prizes for the best entries (amongst the prize is the very sought-after PhpStorm Elephpant, of which we only have a handful left).

I hope people will have fun with it :)

▲Tade0 7 hours ago | parent | next [-]

Pitch this to whoever is in charge of performance at Wordpress.

A Wordpress instance will happily take over 20 seconds to fully load if you disable cache.

▲tracker1 2 hours ago | parent | next [-]

Wordpress is something that I cannot believe hasn't been displaced by a service that uses a separate application for editing and delivery.

It seems like something like vercel/cloudflare could host the content-side published as a worker for mostly-static content from a larger application and that would be more beneficial and run better with less risk, for that matter. Having the app editing and auth served from the same location is just begging for the issues WP and plugins have seen.

▲devmor 2 hours ago | parent [-]

As someone who built full ecommerce websites on wordpress over 15 years ago, I can tell you exactly why it hasn't been replaced - the plugin/theme ecosystem.

There are tens of thousands of plugins and themes to make a Wordpress website do whatever you want and look however you want, either for free or a very low fee. You have to replace that entire ecosystem for the same price to replace Wordpress.

No matter how many times people get hacked, the perceived value of getting something for nothing outweighs the eventual cost.

▲hparadiz an hour ago | parent | next [-]

I did a short contract a few years back where multiple WordPress plugins were pulling different versions of guzzle and I had to use a namespace rewriter to be able to run multiple guzzle versions at the same time.

The thing about WordPress is you can put it on a box and lock it down so hard you just treat it as an untrusted process on your server.

▲shimman an hour ago | parent | prev [-]

Maybe it's just my poor imagination but how many plugins are truly unique to WP that you can't find on other CMSs? The only ones that come to mind would be those plugins that help connect to various B2B or B2C workflows, is that where the gold is mostly found?

▲AlienRobot an hour ago | parent [-]

WP essentially lets plugins do anything they want. The plugins are just scripts that register callbacks to events. WP calls events on BASICALLY EVERY FUNCTION. This is without exaggeration. I don't remember the exact names right now, but if you have a function like wp_get_title that gets the title of a post, there will be a "get_title" event that can modify which title is returned. So for every function first the data is computed using the default WP way, then plugins are allowed to discard all that work and replace it without something else entirely. There are events for deciding the canonical URL, for deciding the description of a post, for deciding whether RSS links will be displayed or not (the callback just returns true or false), etc.

In other words, every property can be modified through global event callbacks. Some events are called very early in the whole pipeline that let plugins just render whatever they want (e.g. render custom XML sitemaps).

▲embedding-shape 7 hours ago | parent | prev | next [-]

Microbenchmarks are very different from optimizing performance in real applications in wide use though, they could do great on this specific benchmark but still have no clue about how to actually make something large like Wordpress to perform OK out of the box.

▲rectang 3 hours ago | parent | prev | next [-]

Are you talking about a new, empty WordPress instance running the default theme? Because if so, that doesn't match my anecdotal experience.

If you're talking about a WordPress instance with arbitrary plugins running an arbitrary theme, then sure — but that's an observation about those plugins and themes, not core.

As someone who has to work with WordPress, I have all kinds of issues with it, but "20 seconds to load core with caching disabled" isn't one of them.

▲lossyalgo an hour ago | parent [-]

Can concur. I bought a plugin a few years ago after using the free version for many years, wanting to support the devs for making such a useful plugin. I installed it on a few sites, and left my PC running overnight with a tab open to the plugin and woke up the next day to a lovely rebooted Windows (I hate how default Windows behavior after BSOD is a reboot with ZERO indication that it crashed or if it was an update that rebooted). Re-opened all my tabs, and queue the same waking up the next day to a freshly rebooted Windows, which made me suspicious. I assumed at that point it must have been a BSOD, so dug into Windows event logs, eventually realizing it was Firefox. Restored tabs yet again, left browser open over night, while installing more and more debugging tools for Firefox, none of which helped me track down the culprit. What pissed me off the most was that Firefox even allowed a process to consume > 30GB of RAM and cause my PC to crash! I finally caught it one night after > 10 BSODs - the tab had been open for 20+ hours, and right as it started to spiral out of control and my PC was about to crash, as programs were starting to error out and Windows was madly paging things to disk. I got lucky, and was able to open about:memory to see the culprit - this plugin had some kind of memory leak that wasn't noticeable but then suddenly went nuts. I emailed the devs multiple times with the full debug output, and was ignored for weeks until finally they responded, which pissed me off even more having finally paid for the pro version, only to be greeted with this. The free version didn't seem to have this issue either, which was like an extra slap in the face.

Naked Wordpress is plenty fast, but as soon as you start adding sketchy plugins and Themes, things can spiral out of control.

▲rkozik1989 4 hours ago | parent | prev | next [-]

Much like anything else your performance is going to vary a lot based on architecture of implementation. You really shouldn't deploying anything into production without some kind of caching. Whether that's done in the application itself or with memcached/redis or varnish or OPcache.

▲slopinthebag an hour ago | parent | next [-]

Either you use a slow language and deal with caching or you use a fast language and just put Cloudflare/Bunny/etc in front.

▲LoganDark 4 hours ago | parent | prev [-]

> You really shouldn't deploying anything into production without some kind of caching.

Citation needed? You only need cache if a render is expensive to produce.

▲monkey_monkey 6 hours ago | parent | prev [-]

That's often a skill issue.

▲almosthere 3 hours ago | parent [-]

skill issue being they only know php

▲ge96 2 hours ago | parent | prev | next [-]

5 days to 30 seconds? What kind of factor/order of magnitude is that damn

What takes 5 days to run

▲hosteur 2 hours ago | parent | next [-]

Poorly made analytics/datawarehouse stuff.

▲slopinthebag an hour ago | parent | prev [-]

One query per column per row

▲gib444 7 hours ago | parent | prev | next [-]

> A month ago, I went on a performance quest trying to optimize a PHP script that took 5 days to run. Together with the help of many talented developers, I eventually got it to run in under 30 seconds

That's a huge improvement! How much was low hanging fruit unrelated to the PHP interpreter itself, out of curiosity? (E.g. parallelism, faster SQL queries etc)

▲brentroose 7 hours ago | parent | next [-]

Almost all, actually. I wrote about it here: https://stitcher.io/blog/11-million-rows-in-seconds

A couple of things I did:

- Cursor based pagination - Combining insert statements - Using database transactions to prevent fsync calls - Moving calculations from the database to PHP - Avoiding serialization where possible

▲tiffanyh 7 hours ago | parent [-]

Aren’t these optimizations less about PHP, and more about optimizing how your using the database.

▲toast0 3 hours ago | parent | next [-]

PHP is kind of like C. It can be very fast if you do things right, and it gives you more than enough rope to tie yourself in knots.

Making your application fast is less about tuning your runtime and more about carefully selecting what you do at runtime.

Runtime choice does still matter, an environment where you can reasonably separate sending database queries and receiving the result (async communication) or otherwise lets you pipeline requests will tend to have higher throughput, if used appropriately, batching queries can narrow the gap though. Languages with easy parallelism can make individual requests faster at least while you have available resources. Etc.

A lot of popular PHP programs and frameworks start by spending lots of time assembling a beautiful sculpture of objects that will be thrown away at the end of the request. Almost everything is going to be thrown away at the end of the request; making your garbage beautiful doesn't usually help performance.

▲hu3 6 hours ago | parent | prev | next [-]

It's still valid as as example to the language community of how to apply these optimizations.

▲swasheck 6 hours ago | parent | prev [-]

in all my years doing database tuning/admin/reliability/etc, performance have overwhelmingly been in the bad query/bad data pattern categories. the data platform is rarely the issue

▲tosti 5 hours ago | parent [-]

The worst offenders I've seen were looping over a shitty ORM

▲cobbzilla 3 hours ago | parent | next [-]

hey don’t forget, that shitty ORM also empowers you to write beautiful, fluent code that, under the hood, generates a 12-way join that brings down your entire database.

▲edoceo 4 hours ago | parent | prev [-]

And that is true across languages.

▲Joel_Mckay 5 hours ago | parent | prev [-]

In general, it is bad practice to touch transaction datasets in php script space. Like all foot-guns it leads to Read-modify-write bugs eventually.

Depending on the SQL engine, there are many PHP Cursor optimizations that save moving around large chunks of data.

Clean cached PHP can be fast for REST transactional data parsing, but it is also often used as a bodge language by amateurs. PHP is not slow by default or meant to run persistently (low memory use is nice), but it still gets a lot of justified criticism.

Erlang and Elixir are much better for clients/host budgets, but less intuitive than PHP =3

▲CyberDildonics 3 hours ago | parent | prev | next [-]

Using a language that is 100x slower than naive native programs to do a "speed challenge" is like spending your entire day speed walking to run errands when you can just learn how to drive a car.

▲user3939382 7 hours ago | parent | prev | next [-]

exec(‘c program that does the parsing’);

Where do I get my prize? ;)

▲brentroose 7 hours ago | parent [-]

The FAQ states that solutions like FFI are not allowed because the goal is to solve it with PHP :)

▲kpcyrd 6 hours ago | parent [-]

What about using the filesystem as an optimized dict implementation?

▲olmo23 6 hours ago | parent [-]

this is never going to be faster because it requires syscalls

▲kpcyrd 4 hours ago | parent [-]

The time you lose at the syscall boundary you may be able to win back during much shorter GC pauses.

▲cess11 3 hours ago | parent [-]

Some suggestions that are already in the PR list disable GC.

https://www.php.net/manual/en/function.gc-disable.php

▲onion2k 4 hours ago | parent | prev [-]

A month ago, I went on a performance quest trying to optimize a PHP script that took 5 days to run. Together with the help of many talented developers, I eventually got it to run in under 30 seconds.

When people say leetcode interviews are pointless I might share a link to this post. If that sort of optimization is possible there is a structures and algorithms problem in the background somewhere.

▲nicoburns 4 hours ago | parent | next [-]

I find that these kind of optimizations are usually more about technical architecture than leetcode. Last time I got speedups this crazy the biggest win was reducing the number of network/database calls. There were also optimisations around reducing allocations and pulling expensive work out of hot loops. But leetcode interview questions don't tend to cover any of that.

They tend to be about the implementation details of specific algorithms and data structures. Whereas the important skill in most real-world scenarios would be to understand the trade-offs between different algorithms and data structures so that you pick an appropriate off-the-shelf implementation to use.

▲LollipopYakuza 4 hours ago | parent [-]

I agree. The "advanced" leetcode is about those last % of optimization. But when network latency is involved in a flow, it is usually the most obvious low hanging fruit.

▲tuetuopay 4 hours ago | parent | prev | next [-]

Well leetcode asks you to implement the data structure, not how and when to use which data structure. I don’t need to know how to implement a bloom filter on a whiteboard off the top of my head to know when to use it.

▲slopinthebag an hour ago | parent | prev [-]

Do you think they achieved that performance optimisation with a networked service because they switched from insertion sort to quicksort?

▲hparadiz an hour ago | parent [-]

I did the same thing in PHP before. Issue was a foreach over a foreach with a search. The fix was to build the result set as you populate the main array of objects. Basically as you add stuff to the array if there's a value that matches you throw it into another "results" array for any cardinality (unique value) that exists. Since in PHP objects are always just pointers your results arrays are relatively painless. Just a series of int32 integers basically. Then when you need an answer your result is instant. I ended up getting a 80-90% speed up. This is not just a php thing either. Folks end up doing this type of stuff in every language.

▲chrismarlow9 an hour ago | parent | prev | next [-]

I don't have time to put together a submission but I'm willing to bet you can use this:

https://github.com/kjdev/php-ext-jq

And replicate this command:

jq -R ' [inputs | split(",") | {url: .[0], date: .[1] | split("T")[0]}] | group_by(.url) | map({ (.[0].url): ( map(.date) | group_by(.) | map({(.[0]): length}) | add ) }) | add ' < test-data.csv

And it will be faster than anything you can do in native php

Edit: I'm assuming none of the urls have a comma with this but it's more about offloading it through an extension, even if you custom built it

▲Retr0id 37 minutes ago | parent [-]

The rules exclude FFI etc.

▲Xeoncross 6 hours ago | parent | prev | next [-]

This is why I jumped from PHP to Go, then why I jumped from Go to Rust.

Go is the most battery-included language I've ever used. Instant compile times means I can run tests bound to ctrl/cmd+s every time I save the file. It's more performant (way less memory, similar CPU time) than C# or Java (and certainly all the scripting languages) and contains a massive stdlib for anything you could want to do. It's what scripting languages should have been. Anyone can read it just like Python.

Rust takes the last 20% I couldn't get in a GC language and removes it. Sure, it's syntax doesn't make sense to an outsider and you end up with 3rd party packages for a lot of things, but can't beat it's performance and safety. Removes a whole lot of tests as those situations just aren't possible.

If Rust scares you use Go. If Go scares you use Rust.

▲tracker1 2 hours ago | parent | next [-]

Can't speak for go... but for the handful of languages I've thrown at Claude Code, I'd say it's doing the best job with Rust. Maybe the Rust examples in the wild are just better compared to say C#, but I've had a much smoother time of it with Rust than anything else. TS has been decent though.

▲thinkingtoilet 5 hours ago | parent | prev | next [-]

It's almost comical how often bring up Rust. "Here's a fun PHP challange!" "Let's talk about Rust..."

▲hu3 an hour ago | parent | next [-]

Yep. It's like a crossfit vegan religion at this point.

You don't even have to ask. They will tell you and usually add nothing to the conversation while doing so.

Quite off-putting.

▲slopinthebag an hour ago | parent | prev | next [-]

I mean, it's kinda like complaining that people are mentioning excavators on your "how I optimised digging a massive ditch with teaspoons" post.

▲Xeoncross 5 hours ago | parent | prev [-]

Sorry, but it's honestly just a lot of our journeys. Started on scripting languages like PHP/Ruby/Lua (self-taught) or Java/VB/C#/Python (collage) and then slowly expanded to other languages as we realized we were being held back by our own tools. Each new language/relationship makes you kick yourself for putting up with things so long.

▲tracker1 2 hours ago | parent | next [-]

I don't know about that... I like Rust a lot... but I also like a lot of things about C# or TS/JS... I'll still reach for TS first (Deno) for most things, including shell scripting.

▲thinkingtoilet 5 hours ago | parent | prev [-]

I understand that but there's a time and a place. Rust has nothing to do with this. 100% of the people on this site understand that this challenge can be done faster in C, or Rust, or whatever. This is a PHP challenge. Perhaps we could discuss the actual submission as opposed to immediately derailing it.

▲codegeek 5 hours ago | parent | prev [-]

I am not that smart to use Rust so take it with a grain of salt. However, its syntax just makes me go crazy. Go/Golang on the other hand is a breath of fresh air. I think unless you really need that additional 20% improvement that Rust provides, Go should be the default for most projects between the 2.

▲Xeoncross 5 hours ago | parent [-]

I hear you, advanced generics (for complex unions and such) with TypeScript and Rust are honestly unreadable. It's code you spend a day getting right and then no one touches it.

I'm just glad modern languages stopped throwing and catching exceptions at random levels in their call chain. PHP, JavaScript and Java can (not always) have unreadable error handling paths not to mention hardly augmenting the error with any useful information and you're left relying on the stack trace to try to piece together what happened.

▲pxtail 8 hours ago | parent | prev | next [-]

Side note - I wasn't aware that there is active collectors scene for Elephpants, awesome!

https://elephpant.me/

▲t1234s 7 hours ago | parent | next [-]

Elephpants should be for second and third place. First place should be the double-clawed hammer.

▲thih9 7 hours ago | parent | prev [-]

Excellent project. My favorites: the joker, php storm, phplashy, Molly.

▲normie3000 4 hours ago | parent [-]

I love Mollie!

▲semiquaver 5 hours ago | parent | prev | next [-]

Are they just confused about what characters require escaping in JSON strings or is PHP weirder than I remember?

    {
        "\/blog\/11-million-rows-in-seconds": {
            "2025-01-24": 1,
            "2026-01-24": 2
        },
        "\/blog\/php-enums": {
            "2024-01-24": 1
        }
    }
▲idoubtit 4 hours ago | parent | next [-]

The weirdness is partly in JSON . In the JSON spec, the slash (named "solidus" there) is the only character that can be written plainly or prefixed with a backslash (AKA "reverse solidus").

See page 4, section 9 of the latest ECMA for JSON: https://ecma-international.org/wp-content/uploads/ECMA-404_2...

▲daviddoran 5 hours ago | parent | prev | next [-]

PHP has always escaped forward slashes to help prevent malicious JSON from injecting tags into JavaScript I believe. Because it was common for PHP users to json_encode some data and then to write it out into the HTML in a script tag. A malicious actor could include a closing script tag, and then could inject their own HTML tags and scripts etc.

▲CapitaineToinon 5 hours ago | parent | prev | next [-]

That's the default output when using json_encode with the JSON_PRETTY_PRINT flag in php.

▲idoubtit 4 hours ago | parent [-]

> That's the default output when using json_encode with the JSON_PRETTY_PRINT flag in php.

JSON_PRETTY_PRINT is irrelevant. Escaping slashes is the default behavior of json_encode(). To switch it off, use JSON_UNESCAPED_SLASHES.

▲CapitaineToinon 3 hours ago | parent [-]

Ah, my bad. Thanks for the correction, TIL!

▲poizan42 5 hours ago | parent | prev [-]

> The output should be encoded as a pretty JSON string.

So apparently that is what they consider "pretty JSON". I really don't want to see what they would consider "ugly JSON".

(I think the term they may have been looking for is "pretty-printed JSON" which implies something about the formatting rather than being a completely subjective term)

▲ourmandave 2 hours ago | parent [-]

Pretty JSON not meaning formatting, but more "That was pretty JSON of you."

▲matei88 an hour ago | parent | prev | next [-]

It reminds me of a good read about optimizing PHP for 1 billion rows challenge. TLDR; at some point you hit a limit in PHP’s stream layer

https://dev.to/realflowcontrol/processing-one-billion-rows-i...

▲tveita 7 hours ago | parent | prev | next [-]

> Also, the generator will use a seeded randomizer so that, for local development, you work on the same dataset as others

Except that the generator script generates dates relative to time() ?

▲Retr0id 7 hours ago | parent | prev | next [-]

How large is a sample 100M row file in bytes? (I tried to run the generator locally but my php is not bleeding-edge enough)

▲brentroose 7 hours ago | parent [-]

Around 7GB

▲csjh 4 hours ago | parent | prev | next [-]

Obligatory DuckDB solution:

> duckdb -s "COPY (SELECT url[20:] as url, date, count(*) as c FROM read_csv('data.csv', columns = { 'url': 'VARCHAR', 'date': 'DATE' }) GROUP BY url, date) TO 'output.json' (ARRAY)"

Takes about 8 seconds on my M1 Macbook. JSON not in the right format, but that wouldn't dominate the execution time.

▲cess11 3 hours ago | parent [-]

This log in one of the PR:s claims a 5.4s running time on some Mac.

https://github.com/tempestphp/100-million-row-challenge/pull...

▲poizan42 5 hours ago | parent | prev | next [-]

> The output should be encoded as a pretty JSON string.

...

> Your parser should store the following output in $outputPath as a JSON file:

    {
        "\/blog\/11-million-rows-in-seconds": {
            "2025-01-24": 1,
            "2026-01-24": 2
        },
        "\/blog\/php-enums": {
            "2024-01-24": 1
        }
    }
They don't define what exactly "pretty" means, but superflous escapes are not very pretty in my opinion.
▲kijin 5 hours ago | parent [-]

They probably mean "Should look like the output of json_encode($data, JSON_PRETTY_PRINT)". Which most PHP devs would be familiar with.

▲poizan42 5 hours ago | parent [-]

It sounds plausible, but they really need to spell out exactly what the formatting requirements are, because it can make a huge difference in how efficiently you can write the json out.

▲maleldil 3 hours ago | parent [-]

It's a challenge for PHP programmers. I imagine the relevant people would recognise that format.

▲spiderfarmer 8 hours ago | parent | prev | next [-]

Awesome. I’ll be following this. I’ll probably learn a ton.

▲tomaytotomato 3 hours ago | parent | prev [-]

Tempted to submit a Java app wrapped in PHP exec() :D