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Comment by terra_t | Hacker News Reader

It's a funny thing.

Very powerful and scalable parallel SQL-based RDBMS systems have been commercially available for a long time. Also, I think that scalability concerns about ACID are exaggerated: ACID doesn't reach Facebook or Amazon scale, but there's only 5,000 or so sites that are that big.

A converse question to the one they ask is, "Why aren't web developers interested in Commercial Parallel RDBMS" and I think the answer to that is that there are a generation of us who grew up using open source databases, who find the thought of using a commercial database like sticking their hand in a toilet... Even if it's a reasonably priced product like SQL Server's Web Edition.

A lot of people see mysql and pgsql as going nowhere, so there's a lot of interest in something like mongodb which has a future.

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On the contrary, almost all of Facebook's data is stored in SQL systems. Cassandra and such were developed as ephemeral stores for certain types of data, like lists of people who "Like" certain things, but ultimately even that data is backed by SQL. (As far as I understand from my friends who work there.)

> pgsql as going nowhere

Eh?! They just released a major update with long-awaited functionality!

pgsql has a badly nonstandard type system (lots of SQL queries that work in Oracle & mysql don't work in pgsql.) I've still got a long list of queries that run 100x faster in mysql than pgsql

I'm very confused by this comment. Did you switch mysql and pgsql in this comment, or was this what you meant as written?

MySQL has always struck me as having a non-standard and quite strange type system (broken time/date types without microsecond accuracy, explicitly sized text types, ...). I've always seen PostgreSQL being marketed as a drop in replacement for Oracle due to superior standards support. If anything, PostgreSQL seems much more similar to Oracle than MySQL.

I'm also very curious what sorts of things I should avoid if you really do have a very long list of queries that PostgreSQL handles really poorly.

you can write

select sum(x=1) from y;

in standard SQL, Oracle, and Mysql. True == 1 in standard SQL, False == 0. Both pgsql and Microsoft SQL server define a nonstandard boolean type that requires you to add a cast or an if statement, bulking up the query.

I did a shootout of mongodb and the three RDBMS systems (!Oracle) I mention for building a system to represent data from Freebase. It was possible to make a VARCHAR(4096) in mysql and only index the first 64 characters which meant I could map freebase types to mysql tables without running into index limitations -- I wanted the better GIS capabilities in pgsql, but I didn't want to double the size of my tables and queries to be able to handle strings losslessly.

Did the new functionality include reliable replication?

Actually, yes: http://developer.postgresql.org/pgdocs/postgres/release-9-0....

Awesome. Was an honest question, don't do a lot of mysql or postgres these days.

Geez, touchy subject I guess.

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