j-kidd · HackerTrans

11 yıl öncediscuss

Double indentation looks rather ugly though. I like the "K&R" style much better (as shown in comment from bpicolo):

    def some_descriptive_function_name(
        one_parameter,
        another_parameter,
    ):
        some_functionality()

Anyway, either one is superior to 'indent to sibling', where the lines are now tightly coupled to each other.

j-kidd

11 yıl öncediscuss

Chomsky and Superbowl Party: http://www.thebrushback.com/Archives/noamchomsky_full.htm

Perfect article for those on HN who follow pro sports ;)

j-kidd

12 yıl öncediscuss

This shall be a great fit for the NAT/Bastion instance, since the high-availability setup has a few drawbacks: https://aws.amazon.com/articles/2781451301784570

j-kidd

12 yıl öncediscuss

You shall read this first: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1331150

There was a rather significant change to the kernel ARP caching behavior introduced in early 2013: https://github.com/torvalds/linux/commit/2724680bceee94eac39...

It seems to work fine everywhere, except in EC2 VPC, where the arp cache can sometime becomes stale. We too reported this issue to AWS support, but have no idea if they are doing anything about it.

The workaround is to apply a sysctl change to revert to the old behavior prior to the commit. Or to use a subnet larger than /24 to reduce the chance of getting the same IP.

j-kidd

12 yıl öncediscuss

Looking at the examples from the official documentation, I agree with your sentiment. Indeed, the conciseness can cause some confusion to people familiar with the existing scoping rules.

IMHO, it's a good thing if LATERAL is only added as some kind of syntactic sugar. I once had to use LATERAL in DB2 as a band-aid solution for its broken scoping rules: https://www.ibm.com/developerworks/mydeveloperworks/blogs/SQ...

j-kidd

12 yıl öncediscuss

Also from http://stackoverflow.com/a/16553503 by the author of SQLAlchemy:

> Do you have any estimates on how much time is wasted, compared to the rest of the application? Profiling here is extremely important before making your program more complex. As I will often note, Reddit serves well over one billion page views a day, they use the SQLAlchemy Core to query their database, and the last time I looked at their code they make no attempt to optimize this process - they build expression trees on the fly and compile each time.

j-kidd

12 yıl öncediscuss

I feel rather underwhelmed by the performance improvement touted by adequate records. Perhaps someone from the rails community can do something like this: http://techspot.zzzeek.org/2010/12/12/a-tale-of-three-profil...

j-kidd

12 yıl öncediscuss

So, with T2 instances and General Purpose volumes, Amazon is now officially in the overselling business. Kudos to them for finding a way to do it fairly. Looks like extra tough time ahead for lowendbox sellers.

j-kidd

12 yıl öncediscuss

The jmespath library from boto is quite similar to this, and possibly has way more traction. Some differences:

- jmespath uses `body.translations[0].language` instead of `body.translations.0.language`, and it can also do `body.translations[].language`.

- jmespath doesn't support the "missing" use case

j-kidd

12 yıl öncediscuss

This is not strictly about Ruby vs Python. Having used Pyramid (+SQLAlchemy) and Rails, I think the former is plenty fast enough such that no user cares about silly optimization, while the latter is the opposite.

Loading the Rails environment is just too slow, thus you need a preloader such as Zeus or Spring. And then you need something like Guard to make unit testing semi-bearable. But running the whole test suite would still be too slow, so you need parallel_tests to spread the tests across multiple cores (and multiple databases). And finally you drink the PORO kool-aid and start decoupling your codebase from Rails stuffs, and end up debating with DHH in HN.

j-kidd

12 yıl öncediscuss

In my opinion, the full explanation is too long to be put as code comment, but is just right as the commit message. The best way is to keep the commit message, but add a short comment like:

    // Hack to trigger layout change in latest Mozilla

Then, whoever interested in the hack can read the full explanation from the commit message.

Basically, for simple code with unclear purpose, I'd go with short comment in the code plus full explanation in the commit message. For hard-to-read code with complicated logic, I'd go with long comment in the code. Or refactoring.

Ticket description, commit message, code comment, and the code itself are all necessary to keep the codebase "documented".

j-kidd

12 yıl öncediscuss

Good article, but I think it touches too little about persistence. The trade-off of EBS vs ephemeral storage, for example, is not mentioned at all.

Getting your application server up and running is the easiest part in operation, whether you do it by hand via SSH, or automate and autoscale everything with ansible/chef/puppet/salt/whatever. Persistence is the hard part.

j-kidd

12 yıl öncediscuss

Here's my old school setup:

Deployment: `easy_install -U` from a local pypi

Packaging: `setup.py bdist_egg` and `setup.py bdist_wininst`

Dependencies: declare in setup.py, fetch via yolk

To test if everything works, just create a blank virtualenv and easy_install.

This has been working fine for me for years on Linux and Windows.

j-kidd

13 yıl öncediscuss

With SQLAlchemy, I have done similar optimizations against mssql by changing a few lines of ORM code. Without SQLAlchemy, I imagine I'd have to change dozens of hand written SQL queries.

A good ORM helps you to generate the exact SQL you need.

j-kidd

13 yıl öncediscuss

I am pretty sure SQLAlchemy will translate that into:

    UPDATE purchase SET downloads_left=%(downloads_left)s WHERE purchase.id = %(purchases_id)s;

By the way, the posted code has an off-by-one error, as it should do the checking first before the minus operation. Also, the line `db.session.add(purchase)` is redundant.

EDIT: remove bad sample

j-kidd

13 yıl öncediscuss

> I don't know if you've looked at the graph of a Git repo where people merge instead of rebase

We use merge instead of rebase. Here's a snapshot of the graph:

  | | | | | | | | | | | | | | |                  
  * | | | | | | | | | | | | | |
  |\ \ \ \ \ \ \ \ \ \ \ \ \ \ \
  | |_|/ / / / / / / / / / / / /
  |/| | | | | | | | | | | | | |
  | | | | | | | | | | | | | | |

There are only 4 people working on the repo.

j-kidd

13 yıl öncediscuss

Outside of US and EU, it is quite difficult to find a reputable and affordable dedicated hosting provider. We use AWS extensively in ap-southeast-1, and their new C3 Compute Optimized instances are actually very competitive in price-performance ratio. Previously, we mostly used C1 instances, which were just okay. I never like the M1 / M3 instances.

Besides, in this region with messy peering agreement, AWS network also has the lowest ping time and the fewest hops.

j-kidd

13 yıl öncediscuss

Try replacing /etc/nginx/fastcgi_params with the one from http://wiki.nginx.org/PHPFcgiExample

Also, the packaging is done differently by ubuntu and nginx upstream, so I don't think you can just replace it. They are also bundled with different modules. For example, I have to use the package from ubuntu because the one from nginx upstream lacks the geoip module.

j-kidd

13 yıl öncediscuss

It looks like the Multi-AZ setup is using block level replication such as DRBD instead of the built-in replication:

> Database updates are made concurrently on the primary and standby resources to prevent replication lag.

Makes me feels better for setting up my own pg cluster on EC2 a week ago, which does allow reads from the replication slave. Plus, I can provision <1000 IOPS (provisioned IOPS is damn expensive with AWS), and get to use ZFS.

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