Re: Opinions on ext3 vs XFS vs reiserfs for LAMP server
On Thu, Aug 23, 2007 at 02:57:10PM -0500, Neil Gunton wrote:
> That's ok, everybody's free to choose of course. I just get irritated
> when people start wheeling out the same old tired canards every time
> anybody so much as mentions MySQL. It just gets old.
>
> I did look at PostgreSQL a long time ago, can't remember when, but at
> the time the PostgreSQL zealots were all telling me that it was way
> better than MySQL. But then, digging more deeply, I discovered that
> PostgreSQL had something like an 8k row size limit, which seemed absurd
> to me. And no built-in fulltext indexing. And no replication. Also, it
> needed constant vaccuuming. And it turned out there were problems with
> table corruption. And then I found out that PostgreSQL was really
> incredibly slow. So at that point I started taking the people who pushed
> PostgreSQL as being God's Gift to DBA's with a hefty pinch of salt. Of
> course, those specific issues have long been addressed, but the point
> is, the fanboys were all telling me that PostgreSQL was way better than
> MySQL when it *definitely* had those limitations. So why should I
> believe them any more now?
Yes postgres back in the 6.x and early 7.x series had some limits. It
never seemed slow to me, and the vacuuming issue seems to be long gone
(and it often ran fine without having it done for a long time). Of
course at that time the only databases with replication were expensive
high end ones. That is pretty much still true since the replication
option on mysql requires using a different backend which looses a bunch
of the other mysql features, and is as far as I can tell still rather
questionable in use. Since then postgres has got much faster, has
amazingly good locking (mysql is starting to do OK at that, which really
helps on multi user access), and the vacuum maintainance issue seems to
be gone. Postgres certainly still has by far the more complete SQL
command set and support for sub selects and such, which for some
problems is very very useful and can give a huge speedup.
> There are issues with any software package, PostgreSQL included, however
> ACID it may be by design there are other problems which you only find
> out about when you actually put the thing into production. In every
> slashdot discussion about this subject, somewhere buried in there you'll
> find someone who says they tried to shift to PostgreSQL for production
> use and it was simply horrible, slow etc and they shifted back to
> something else. Usually they get shouted down.
Well I have seen moves from postgresql to oracle in order to gain
replication and such. You generally don't see moves from postgres to
mysql, and rarely the reverse either.
> I don't love MySQL, it's just a tool. I don't hate PostgreSQL, it's just
> a tool. They both have their own pluses and minuses. I just wish people
> would stop trying to pretend that PostgreSQL is the only "real" database
> option and MySQL is "just a toy". It's really irritating. I like to use
> what works, and MysQL *definitely* works. I don't like people being
> misleading, and that's what those early fanboys were being when they
> tried to get me to use PostgreSQL over MySQL. And I think they are still
> being misleading when they try to pretend that MySQL is somehow
> introducing "risk" into my system.
If all you do is store indexed data in some tables, then mysql does
great, and is pretty fast at it too. If you have complex relationships
and want to do queries that use other query results as filters, then you
will find postgres far superior to mysql. Some people think subselects
are essential, in which case to them, mysql is just a toy database. If
you don't use such features then mysql is great.
> But here we go again, this is turning into yet another MySQL vs
> PostgreSQL discussion. I don't really want to talk about PostgreSQL
> here, I'm sure it's a Very Fine Database and all but it's irrelevant to
> this discussion. This was supposed to be a question about filesystems,
> not databases, so I guess I'll just leave this little tangent at that.
They are hard to avoid. :)
--
Len SOrensen
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