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PostgreSQL vs. MySQL comparison
prostoalex writes "Ever find yourself wondering which open source database is the best tool for the job? Well, wonder no more, and let your tax dollars do the work in the form of Fermi National Accelerator Laboratory publishing this unbiased review of MySQL vs. PostgreSQL. After reading it, however, it seems that MySQL ranks the same or better on most of the accounts." My poor sleepy eyes misread the date of posting on here; caveat that this is more then 15 months old.
1. There's no such thing as unbiased. Especially on a page that gives a fairly abstract review.
2. This article is 2 years old. Everything in its comparisons is out of date.
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From the site:
"Last modified: February 15, 2005."
postgresql has a native Win32 version, complete with an installer, service support and does not depend on cygwin.
Foreign keys are more than nice, they are essential. Unless, maybe you don't care about the integrity of your data or want to make the necessary checks in their application. The latter should keep their eyes down and their mouth shut if the talk is about 'speed' of any rdbms, off course.
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I have been involved with a smallish ("hundreds") installation of Movable Type using a mysql backend.
One comment spammer can completely annihilate it.
One developer I talked to once did some testing. On one simultaneous connection, mysql was way faster. By five or so, they were close. At ten, PostgreSQL was definitely winning. At a hundred, he was simply unable to get a single MySQL server to complete the test successfully, let alone do it quickly.
The impression I get is that PostgreSQL uses more robust algorithms, with higher constant costs and lower quadratic costs. In any event, never had any problems.
As noted elsewhere, these comparisons are quite old...
But in any event, in my own experience, mysql is a lot easier to blow up by overloading than postgres is, at least if you have a lot of writes going on. For pure-lookup functions, it might do better -- but a lot of modern database apps are pretty compulsive about saving at least something every time someone touches them. (For instance, modern vBulletin saves last visits, threads seen, and so on; all of that adds up to a huge load on the database server.)
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This is unbiased? Give me a break.
WTF is with putting up an "unbiased comparison" between Postgres 7.2 and MySQL 5.0 when Postgres is now up to 8.2 and has most of their concerns addressed in that release, whereas MySQL is still at 5.0?
MySQL is a great database, if you need clustering but not referencial integrity or ACID compliance, that is.
-1 Uncomfortable Truth
1 -- This article is years old.
2 -- This article is posted solely to stir up (repetitive) discussion.
3 -- This article pretends that MySQL is a real database, even though in order to do so it has to make gigantic leaps like considering data integrity to be not really all that important in a database.
4 -- This article trolled me.
Whence? Hence. Whither? Thither.
It's been a long time since any of their PostgreSQL statements were true. It's a very happy native windows service with a nice installer, and the administrative interface is very easy to use. Let's try posting current reviews of software, rather than reruns from a year or two ago.
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You have to give the Notepad guys credit for the fact that it is an incredibly easy product when it comes to configuring it for your needs. For me, out of college, going to Vim was a culture shock because the process of learning Vim was so convoluted and drawn out for simple stuff. I know that Vim and Emacs can be much more powerful than Notepad, but there is something to be said for how easy it is for a developer to install Notepad and just start working with it.
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That'd be because the article was written in 2005. Unbiased? Maybe. Vague, unscientific and out of date? Definitely.
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Foreign keys aren't "nice", THEY ARE ESSENTIAL TO A RDBMS.
It is the same thinking that probably made the retards at MySQL AB make a datatype that accepts 30th February as a date. (At least did, a few years ago.) Why EVEN include a datetime datatype if it isnt capable of the SIMPLEST validations ever.
Yes, I'm fuming. Those MySQL retards has made a generation of programmers think they can do SQL when they manage to put crap into MySQL. Gahhh, I hope their puny webapps will haunt them down sometime.
(I was once searching for a simple webbased forum, and tested phpnuke. It had the following gem to display the 5 most recent articles in the database:
1. "SELECT * FROM ARTICLES ORDER BY ID DESC"
2. Retrieve all articles from the database
3. Then a for loop printing out the 5 first entries.
They basically transferred all data in the articles database everytime, just to iterate over the 5 first rows. Gahhhhhh)
I call pure, unadulterated crap on this one.
One of the major new features in Postgresql 8 was native Windows support. It runs just fine as a service.
This comparision is either very old news, incompetence in action, or, um! strongly biased.
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According to TFA, 'MySQL does very good job even on the busiest sites,' while for PostgreSQL 'Random disconnects, core dumps and memory leaks are usual.' This flies in the face of my own experience and testing results I have seen. Under heavy load, PostgreSQL has a habit of slowing to a crawl, while MySQL just dies. How many web pages have you seen where the entire text was a PHP error saying it was unable to connect to the MySQL server?
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Bingo!
It doesn't cease to amaze me, when the Mysql croud argues that "you don't really need those pesky integrity stuff, it just slows down the database."
Guess what guys; You're dead wrong!
Any DBA worth his salary will enforce data integrity on the lowest possible level, which means constraints (however implemented) on the object level.
Sure, you can let your coders in Bengaluru ensure that the primary key is unique instead of just applying a unique index and the same goes for referential constraints between tables. You can implement them in the application just fine until somebody overlooks some minor detail in the code and you're royally fucked!
Again! Foreign keys or triggers are not "niceties". They are essential in implementing an industry strength database; period!
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>Foreign keys don't speed anything up, they just add an extra layer of checks on your database. Right, they even make the dbms slower. But the dbms certainly does it faster than the application you write. So, to rely on the checks being made in the application results in a waste of speed on the application side. If I don't care about the speed in the application, why make a fuss about the speed of the rdbms? By the way: I rather have things reliable than fast. Subselects are something I also heavily use (and thus mainly stay away from MySQL) although I think it's better to use views for queries performed more than once in a while. Probably one of the main reasons for the spread of MySQL is the fact that is is frequently pre-installed.
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This almost seems like the same comparisons we've been hearing for years.
1) Postgresql is more full featured than MySQL
2) MySQL is faster in a read-mostly environment
That's pretty much the same as the anecdotal arguments have been for years.
In my job, we moved from mysql to postgres several years ago (around PG 7.0). At the time, we needed to make the move for performance reasons. We are in a read-write system, and MySQL's locking was killing us (this was before InnoDB was well established). The features are better too, as our developers were used to having data integrity features, server side programming, and all of the SQL92 constructs available. We also learned a bit about PG performance, which I'll share.
1) Run EXPLAIN ANALYZE on everything. Postgresql is touchier about query performance than MySQL was. This just needs to be a habit if you're using PG. (You really should do performance analysis no matter your DB. It's just a good practice). The biggest gain will be making sure you're using index scans rather than sequential scans.
2) Use persistent connections. Everyone likes to point out the forking issue with PG vs. MySQL's threaded. PG's connection handling is slow, there's no doubt about it. But there's an easy answer. Just limit how often you connect. If you can keep a connection pool, and just reuse those connections, you'll save this big hit.
3) Full vacuum and reindex regularly. We've found the docs to be a bit off on this. It indicates that you should run these occasionally. If you're in a read-write system, a full vacuum on a regular basis is very important. It really doesn't take that long if you do it regularly. Also, we've had trouble with indexes getting unbalanced (we see 50->90% tuple turnover daily). This has gotten better, but it doesn't hurt to let your maintenance scripts make things ideal for you. So, we run a full vacuum and reindex of our tables nightly through cron.
4) Get your shared memory right. PG's shared buffers is probably the most important config attribute. It controls how much of your DB is memory resident vs disk resident. Avoiding disk hits is a big deal for any DB, so get this right. If you can fit your whole DB in memory, then do it. If not, make sure your primary tables will fit. The more you use the shared memory, and the less you have to page data in/out, the better your overall performance will be.
Most DB systems seem to be read-mostly, so I can understand the performance comparisons focusing on that. In our read-write system though, the locking was the biggest issue and it tilted the performance comparison toward PG.
MySQL/MyISAM is the one with the massive legacy code base, the one that your open-source blogging software uses and probably the one that your web host supports. It beautifully hits the "sweet spot" for data-driven web sites with infrequent and simple updates, where trading integrity for "read only" performance is sensible. It does not even purport to compete with PostgreSQL on features - but it does offer fulltext searches, again
MySQL/InnoDB is the one that offers transactions, foreign keys etc. (ISTR it doesn't do fulltext indexes, though) - this is the "version" that bears comparison with PostgreSQL. I wonder how its user base compares?
(OK - you can mix InnoDB and MyISAM tables in a single database, but you can't use InnoDB if your web host hasn't installed it - heck, one provider I use is still on MySQL V3.23)
Flamewars have tended to pit PostgreSQL against a mythical database with the performance of MyISAM and the features of InnoDB...
As for the GUI software, the MySQL GUI Admin/query browser stuff is shinier than PgAdmin3 - but the MacOS version of the former is a complete crashfest! Neither of them steps up to the plate of providing a FOSS equivalent of (the good bits) of MS Access.
In a survey of 100 programmers, 111111 thought that duck-typing was a good idea.
Part of me sees the point you're making, but another part of me say "Yea, and ... what?" Does Notepad, embarrassingly simple though it may be, not still have appropriate uses?
Short answer: No.
Longer answer: None at all.
Untrue.
e rcial-license.html
...
The client library is GPL. That means you cannot create a commercial program that uses it without using the commercial licensed version. Which is $200 per client
You can't even create a library and not ship mysql - the mysql site is very clear that they consider distributing a program that *uses* mysql as being exactly the same as distributing mysql itself:
http://www.mysql.com/company/legal/licensing/comm
Typical examples of MySQL distribution include:
* Selling software that requires customers to install MySQL themselves on their own machines.
Specifically:
* If you develop and distribute a commercial application and as part of utilizing your application, the end-user must download a copy of MySQL; for each derivative work, you (or, in some cases, your end-user) need a commercial license for the MySQL server and/or MySQL client libraries.
This makes mysql unusable for anything except large products. Our entire product only cost $70 for the single user version. No way in hell we're upping the price by $200 a copy.
Ok, this is yet another outdated report comparing three mainstream RDBMS'es - MySQL, PostgreSQL and ORACLE. It was done for yet another physical experiment - for choosing the proper system for storing data about the construction process of one of the LHC detectors - ALICE.y k/db_compare/db_compare.html
And this report is at least professional, which cannot be said about the one mentioned in the article.
http://dcdbappl1.cern.ch:8080/dcdb/archive/ttracz
http://tweakers.net/reviews/657
They compare PostgreSQL 8.2 vs MySQL 4.1.20 and MySQL 5.1.20a.
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Actually it shouldn't (in this context). Typically, one database will have several client applications attached to it. If data consistency is not checked at DB level, then:
Emphasis mine. In other words, You don't have to pay the $200 if your project is itself compliant with the GPL or similar license scheme.
"Comply with the GPL or pay us $200 to legally use our code or libraries" is not the same as saying "You have to pay us $200 if you plan to sell software you made using our code or libraries."
=Smidge=
Well, I sure hope you never work on anything serious.
The database's function is to provide a RELIABLE storage for your data. Part of the whole reliability thing is making sure crap can't get in, because once it's there everything goes to heck.
For instance, let's take a shopping cart. Can an order be for a negative quantity? If your app doesn't work that way (it could, using a negative amount for returns for example), and you still allow it in the DB, then all your reporting goes to heck, as SELECT SUM... now returns the wrong thing.
A proper database is set up in such a way that every piece of data in it makese sense. This means for instance not having things like orders hanging around without in the void without being linked to some client. This is something easily ensured by foreign keys. Otherwise you have an utter mess - the total of the orders in the database doesn't match the sum of the orders of all clients!
If you put your checks in the database, you have a guarantee that when somebody else codes another frontend to it (say, you had a website and now are making a special version for PDAs), if the application does the wrong thing, the database simply won't let it happen. This may cost a bit of speed, but I assure you that peace, your sanity and your ASS (if you have a boss and he's got any sense, he's not going to like it at ALL if it turns out that reports don't match reality, and that reality can't be even easily extracted) is far, far more valuable.
I had to make a decision recently between Mysql and Postgresql for a database composed of many tables with greater than 50,000,000 rows. While going through the decision making process, I loaded a sample table with 50,000,000 rows to do some benchmarks. The first thing I had to do to run my tests was index the table. I started with Mysql using a InnoDB table type. I had both database servers relatively tuned to the hardware they were running on. I ran the create index with MySQL and detached my screen session. I came back several hours later to find MySQL was doing something along the lines of INDEX via REPAIR SORT. After some reading, I learned that this takes an order of magnitude longer than building an index the "normal" way and is caused by the index becoming corrupted during the creation. Okay... so, I restarted this process several times and encountered the same problem. This is clean data mind you that has already been exported from an existing SQL server. I duplicated my install on a second server and had the same problems. Very annoyed with MySQL, I gave Postgres a try. It worked on the first time in less than 25 minutes without issue. Since then I've been using it on 250,000,000 row datasets without issue. It's always reliable, and as long as you remember to use CURSORS for huge SELECT statement, it's painless to work with.
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From the comparison table:
These statements convey the same information but that the author has presented them in different lights suggests to me a premeditated bias in favour of MySQL.
Umm, I'm pretty sure that MySQL had had subselects for several years. It's not clear if you knew that or not.
Does the Internet's favorite DBMS have an IP address datatype yet?
How about MAC address? CIDR block?
"An IP address is just a 32-bit unsigned int, duh. Any DBMS can store those."
Wrong. A datatype isn't just about storage, but also about operations. In PostgreSQL, when you do a SELECT across a table with IP addresses in it, you get them formatted and displayed as IP addresses, not as opaque ints. Likewise with CIDR blocks, like "192.168.42.0/23". There's also a comparison operator for asking whether an IP address is within a CIDR block.
If you're implementing a network registration system or an incident logging system, how much of your time do you want to waste staring at opaque ints like 3232246272 rather than IP addresses like 192.168.42.0 when you're trying to debug it?
MySQL is a bimbo, a fratboy: it's easy, but so shallow! The amount of time you save in one-time setup, you will lose many times over in all the little annoyances and deficiencies of a DBMS that was originally designed by folks who didn't really believe in DBMSes. Over time they've slowly been shamed into including many of the features they used to despise: transactions, relational integrity checks, and so on. But there's still so much missing ... not just essential integrity features, but little fiddly bits like good datatype support, the kinds of things that make your life easier (as a programmer or as a DBA) in the long run.
It's worth pointing out that the parent is not being sarcastic. You can sell it for whatever price you like - but you still have to make the source available, and you can't place any restrictions on your customers selling copies for whatever price they like. In practice, this tends to drive the cost of GPLed software down to $0.
good clarification. but still: does this really hold water? i mean, unless they're using a modified GPL or whatever (is the GPL open-source?), they don't really get to dictate the terms. "derivative work", for example, isn't something they get to define. if i'm shipping a closed-source app that simply requires MySQL be also installed, and not something that's statically linked to their binaries, where's the "derivative work" come in?
i speak for myself and those who like what i say.
Foreign keys don't speed anything up, they just add an extra layer of checks on your database.
Correct. That extra layer of checks will probably actually slow things down a bit.
But foreign keys aren't about performance. They're about data integrity, which I would hope every database administrator or developer is more concerned with anyway. It doesn't matter how many requests/second your DBMS can handle if the data is fuxxored.
Your app should be checking itself anyway.
Yes, it should be catching "foreign key constraint violation" exceptions thrown by the DB interface and handling them appropriately. I hope that's what you meant.
MysSQL has a much larger user base than PostgreSQL, therefore the code is more tested and has historically been more stable than PostgreSQL and more used in production environments.
"Claiming that your RDBMS is the best in the world because more people use it is like saying McDonalds makes the best food in the world."
Sorry, just an old joke that deserved retreading... ;)
"I can be self-referential if I want to," said Tom, swiftly.
When are you non-database types going to stop saying "Your app should be checking itself anyway."
This is an insanely inneficient method of execution. It's also highly presumptive.
Inneficient: If you are going to insert a record you have to first check to make sure it's not there. Then if it is there you have to change your INSERT to an UPDATE. This is dumb. Some databases do a INSERT OR UPDATE. but if they don't, it's faster to do an INSERT, handle failure, UPDATE. Alternatively -- UPDATE and INSERT on ZERO ROWS CHANGED. This means you have to run less than 2 queries on average. Your app should check method guarantees two SQL statements are executed every single time.
Dumb. Say you check for a record to exist. You get a "NO" answer. While you are preparing and executing your next INSERT, some other process or a thread inserts that same record into the databse. Now you have an error and you still don't know what to do. In short, you're in a pretty bad way.
Presumptive. In all my years of living I've never seen any company happy with the only interface to the data being through the application interface. Especially with a database on the back end. The business types, Marketing in partitular, love to screw with database information to try and identify trends, patterns, and correlations between the customer behaviour, product representation, and sales metrics. It is presumptive that the application can safely contain all of the business logic and you can assume that no one will ever come in the back end and change something -- thereby breaking all your business rules.
The other consideration is that the business logic contained in a database is going to run a heck of a lot faster on the database than anything you can dream up in your application, unless the application is written in C. Databases are generally written in C/C++. Applications are generally written in Java,Perl,Python,Ruby. None of these can compete with C. Add to that the fact that databases have been designed for years to do only one thing -- manage data. Do you seriously think you can out perform a decade of database optimization in a ruby script?
If you are going to base an application on data it would be useful to know how to capitalize on the features of a database rather than trying to repeat it. At the very least, you are less likely to introduce bugs.
Additionally, databases generally can do this faster than the application code. I can say this because databases are written in C and optimized and debugged for years. Applications are rarely (relatively) written in C and have not been debugged for years when released.
This is something that actually really pisses me off about Ruby, Rails, and ActiveRecord. ActiveRecord is an insane violation of everything that a database has been built to do. It breaks consistency, violates keys, ignores so many rules... And it's beats the crap out of a database to do what a database is designed to do and can handle much faster.
This is regardless of the flame wars of Postgres vs MySQL.
I suspect you're thinking of relatively simple cases where you have a single application working against a database. Which of course is the standard MySQL scenario.
Where foreign keys and the other referential integrity features really shine is in true enterprise scenarios, when you may have hundreds or thousands of applications, written in multiple languages, working against the same shared database(s).
In that scenario, the only viable way to duplicate the functionality of foreign keys at the application level is to have a middle layer which all other applications are required to go through. Realistically, that middle layer has to be implemented as a server, serving requests for object/record creation, update and delete over the network. Implementing it as a library to be linked into applications doesn't work well, because there are multiple applications accessing the database, and integrity enforcement needs to be centrally coordinated.
Implementing a middleware data server for an application isn't all that difficult, but integrating it into applications can be. Most application development environments know how to talk to databases, but don't automatically know how to talk to your application-specific, language-independent, data server. So now you're writing a client library for each app dev platform used in the enterprise, and dealing with things like integrating your custom interface with data-bound controls in the user interface. BTW, this is where people start resorting to e.g. SOAP, and projects start going off the rails (no pun intended, Ruby fans).
Luckily, as it turns out, there are already standardized, widely-available, well-supported systems that implement a centralized data serving service which enforces referential integrity. They're called databases. And foreign keys are an essential part of the service they provide.
None of this applies when somebody logs in with psql/enterprise manager/whatever and updates something in the database by hand. You can have all the OO and libraries you want, but it doesn't help if the new application doesn't use it. Yesterday we had code in VB6, today we have it in C#. Application is completely different. Guaranteeing that all the VB code will be exactly translated to C# is very, very hard.
On the other hand, the database remains being the same, and all the constraints it has don't care about which language, methodology or whatever is being used. VB, C#, Perl, PHP, are all automatically held to the same constraints.
And what's the problem with that? Use stored procedures and triggers then. Seriously, in a database of any size, forget about any attempts at compatibility with other databases. It only works on very, very trivial applications.
Just take postgres and mysql. PostgreSQL loves big transactions. The overhead for a transaction is high, but it's perfectly happy with large, long running transactions, and the more the better. PostgreSQL will be slow if you have a transaction per statement.
On the other hand, databases like mySQL want tiny transactions because the locks are really problematic. Leave a transaction uncommitted, and quickly things will grind to a halt. On the other hand, on postgresql the worst problem will be the lack of vacuum, which will gradually slow things down, but doesn't cause immediate problems.
If you make it for mySQL, without a redesign it'll suck on postgres and viceversa. If you try to make it for both, it'll be suboptimal on both.