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Craig Kerstiens

Category: Postgres

A simple guide for DB migrations

Most web applications will add/remove columns over time. This is extremely common early on and even mature applications will continue modifying their schemas with new columns. An all too common pitfall when adding new columns is setting a not null constraint in Postgres.

My wishlist for Postgres 9.5

As I followed along with the 9.4 release of Postgres I had a few posts of things that I was excited about, some things that missed, and a bit of a wrap-up. I thought this year (year in the sense of PG releases) I’d jump the gun and lay out areas I’d love to see addressed in PostgreSQL 9.5. And here it goes:

Postgres and Connection Pooling

Connection pooling is quickly becoming one of the more frequent questions I hear. So here’s a primer on it. If there’s enough demand I’ll follow up a bit further with some detail on specific Postgres connection poolers and setting them up.

The basics

For those unfamiliar, a connection pool is a group of database connections sitting around that are waiting to be handed out and used. This means when a request comes in a connection is already there whether in your framework or some other pooling process, and then given to your application for that specific request or transaction. In contrast, without any connection pooling your application will have to reach out to your database to establish a connection. While in the most basic sense you may thinking connecting to a database is quick, often theres some overhead here. An example is SSL negotiation that may have to occur which means you’re looking at not 1-2 ms but often closer to 30-50.

Postgres Datatypes – The ones you're not using.

Postgres has a variety of datatypes, in fact quite a few more than most other databases. Most commonly applications take advantage of the standard ones – integers, text, numeric, etc. Almost every application needs these basic types, the rarer ones may be needed less frequently. And while not needed on every application when you do need them they can be an extremely handy. So without further ado let’s look at some of these rarer but awesome types.

hstore

Yes, I’ve talked about this one before, yet still not enough people are using it. Of this list of datatypes this is one that could also have benefit for most if not all applications.

A year's look at Postgres

A couple years back I started more regularly blogging, though I’ve done this off and on before, this time I kept some regularity. A common theme started to emerge with some content on Postgres about once a month because most of what was out there was much more reference oriented. A bit after that I connected with petercooper, who runs quite a few weekly email newsletters. As someone thats been interested helping give others a good reason to create content the obvious idea of Postgres Weekly emerged.

Since then we’ve now had the newsletter running for over a year, helped surface quite a bit of content, and grown to over 5,000 subscribers. First if you’re not subscribed, then go subscribe now.

And if you need some inspiration or just want to reminisce with me… here’s a look back at a few highlights over the past year:

PostgreSQL 9.4 - Looking up (with JSONB and logical decoding)

Just a few weeks back I wrote a article discussing many of the things that were likely to miss making the 9.4 PostgreSQL release. Since that post a few weeks ago the landscape has already changed, and much more for the positive.

The lesson here, is never count Postgres out. As Bruce discussed in a recent interview, Postgres is slow and steady, but much like the turtle can win the race.

So onto the actual features:

Tracking Month over Month Growth in SQL

In analyzing a business I commonly look at reports that have two lenses, one is by doing various cohort analysis. The other is that I look for Month over Month or Week over Week or some other X over X growth in terms of a percentage. This second form of looking at data is relevant when you’re in a SaaS business or essentially anythign that does recurring billing. In such a business focusing on your MRR and working on growing your MRR is how success can often be measured.

PostgreSQL 9.4 - What I was hoping for

Theres no doubt that the 9.4 release of PostgreSQL will have some great improvements. However, for all of the improvements it delivering it had the promise of being perhaps the most impactful release of Postgres yet. Several of the features that would have given it my stamp of best release in at least 5 years are now already not making it and a few others are still on the border. Here’s a look at few of the things that were hoped for and not to be at least until another 18 months.

Examining Postgres 9.4 - A first look

PostgreSQL is currently entering its final commit fest. While its still going, which means there could still be more great features to come, we can start to take a look at what you can expect from it now. This release seems to bring a lot of minor increments versus some bigger highlights of previous ones. At the same time there’s still a lot on the bubble that may or may not make it which could entirely change the shape of this one. For a peek back of some of the past ones:

Rethinking the limits on relational databases

Theres a lot of back and forth on NoSQL databases. The unfortunate part with all the back and forth and unclear definitions of NoSQL is that many of the valuable learnings are lost. This post isn’t about the differences in NoSQL definitions, but rather some of the huge benefits that do exist in whats often grouped into the schema-less world that could easily be applied to the relational world.

Forget migrations

Perhaps the best thing about the idea of a schemaless database is that you can just push code and it works. Almost exactly five years ago Heroku shipped git push heroku master letting you simply push code from git and it just work. CouchDB and MongoDB have done similar for databases… you don’t have to run CREATE TABLE or ALTER TABLE migrations before working with your database. There’s something wonderful about just building and shipping your application without worrying about migrations.